Anything to gain by using higher resolution than the DVD?

[Skywalkerjen]

Hello

I am about to encode all my DVDs using XviD 1.0.2 so I can use my PC as a video jukebox. I hope to be using this jukebox in 15 years time!
I am encoding with 1-pass constant quant 2 - size is not a problem.

All sources are DVD and the question is this:

Should I encode at 640x480 (which gives exact 1.33:1
Should I encode at 720x544 (which is the same as the DVD)
Should I encode at 1024x752 (which is much higher than the DVD)

Is it worth increasing the resolution (anamorphic examples aside)?
Do the filters add information that make the picture look better?
My computer is able to run 1280x928 without a problem.

The reason I was choosing 1024 is this is the largest horizontal resolution when anamorphic DVDs are "stretched"?

Thank you for your time
Skywalkerjen:cool:

[eichlan]

#1 rule of interpolative mathematics: You cannot gain resolution that doesn't exist in the original through processing.

You can increase the resolution, and if you have filters that add effects that you like, then by all means do it. But technically it can not add anything extra. Despite everyone's best efforts you cannot gain detail through "processing" an image...

In fact, since the DVDs raw source is 720x480 for NTSC even when the aspect ratio is 4:3, you're already losing something since the image had to be stretched to fit the new frame, then stretched back to 4:3 when it's played...In which case, by making the image larger along the Y axis, you're creating extra "useless" pixels, since you know that the source that they started with was 4:3 and then stretched horizontally, you can save yourself time and effort by just making the height 480.

...at least, that's my opinion.

[Skywalkerjen]

Many thanks for taking the time to reply eichlan. Have I understood anamorphic correctly? As I understand it:

For PAL:
DVDs use 720x576. If the movie is in letterbox format, then it would be encoded at: 720x288

However, I thought instead of only using 288 pixels for vertical, anamorphic uses all 576 - (so making everyone look tall). To compensate for this, on playback, the DVD player increases the horizontal resolution (to fatten the image out again).

There are 2.5 horizontal pixels per vertical. (288 x 2.5 = 720)
Now the vertical resolution is 576, so the horizontal must be 576 x 2.5 = 1440pixels

So is the DVD player actually outputing 1440x576 in this anamorphic example? Or (worriedly!) is it more complicated than that?

[Didée]

The old question: Is there any point in upsizing a source prior to encoding?

Common answer: Benefits of doing upsizing are questionable - you won't get any more detail from it. If it isn't in the source, you can't invent it out of thin air. So upsizing means only blowing up pixels and bitrate, without bringing something new to the source. Therefore upsizing is pointless, evil, and never should be done by sane minded people.

But then, why are there tools like e.g EDI upsizers, or scripts like e.g. iiP? Well, probably the inventors are pointless, evil, and not sane minded ;)

No, of course not. There's another reason.

The amount of present detail is one thing. The representation of the present detail is another thing ...

An uber-simple demonstration, a little exaggerated to make the basic problem obvious:

Let's assume we have a 720ish source. Let's further assume we're going to play it back on a 1280ish display (being a rather common resolution for several reasons).

Magnification on a small detail of the original source:
http://img35.exs.cx/img35/7281/1_sourcedetail.png

Playback on a '1280, letting the card resize, looks like
http://img35.exs.cx/img35/4242/3_cardresized.png

This is plain bilinear resizing, which most or all cards are supposed to use, more or less.

Then people suggest to use sharpening on playback through ffdshow ... :rolleyes: ... okay, here we go.

source sharpened by ffdshow, resized by card:
http://img35.exs.cx/img35/9340/4_ffdsharp_cardresized.png

source first resized, then sharpened, both by ffdshow:
http://img35.exs.cx/img35/782/5_ffdresizeansharp.png

Ah, yes. Both versions are very nice indeed, lol.

I prefer to invest more time into pre-processing to the final target resolution, because playback on '1280 should look like

http://img35.exs.cx/img35/240/2_processed.png

or should it not?

[Koepi]

Hehe, very nice explanation Didee :)

Maybe you could add as summary:
"Encoding resized instead of anamorph is useful in the case where you want to have control over the resizing algorithm used, as this algorithm is responsible for a good amount of the quality seen."

Regards
Koepi

[Skywalkerjen]

Many thanks for taking the time to explain that Didee - much appreciated. And to Koepi for the summary.
I understand as follows:

By playing the video at higher resolution, I can "enhance" the quality - make it sharper / reduce noise etc.

I can do this by getting the computer to resize and enhance in realtime by using ffdshow.

Or I can add the enhancement/resize to the file itself (giving me a much larger filesize, BUT giving me more control over the enhancement - this is preprocessing.
Can I assume that for better results, preprocessing is the way to go - as it is not done in realtime, more complex calculations can be carried out?

If I am getting the gist of this, the next logical question is should I be using a more complicated resizing algorithm than Lanczos in Gordian Knot?:cool:

[Koepi]

Not easy to tell the answer to that question.

It depends on how much space you can use for the "final" encode.

If size doesn't matter (i.e. we talk about 90 minutes movie in half dvd size), it is most likely the better choice to do the resize and filtering before encoding.

If you have size constraints (i.e. 700MB cdr), you better use anamorph encoding as it'll save bitrate.

You should test both variants and see what you like best, in the end that's what really matters. There is no one-and-only "scientific truth" to this question.

Regards
Koepi

[SeeMoreDigital]

Originally posted by Skywalkerjen
Many thanks for taking the time to reply eichlan. Have I understood anamorphic correctly? Not quite...

For a "slightly" more detailed explanation (with very little technical jargon), please look here (http://seemoredigital.net/03_Video_Only_Info/What_is_an_anamorphic_encode.html).

This thread could turn out to be quite interesting. Not so long ago I was wondering if there was a conceivable "top-out" bit-rate for Mpeg2 when encoded to DVD anamorphic pixel frame sizes (ie:720x480/576)... I guess the same "top-out" bit-rate question could ba asked about Mpeg4.

EDIT: Personally speaking. I don't think there is any benifit to be had by increasing the quantity of "vertical" pixels from say, 480/576 pixels to 720 pixels. However, I don't have a problem with the idea of increasing the "horizontal" quantity of pixels....

Meaning, a PAL Mpeg2 source with 720x576 "anamorphic" pixels becomes an Mpeg4 encode with 1024x576 "square" pixels.


Cheers

[Sharktooth]

I prefer 1024x576 pixels to 720x576 Anamorphic.
The reason is for the anamorphic encode the image will be resized during playback to Monitor horizontal x Monitor vertical resolution. So the image gets resized vertically and horizontally to fit the monitor resolution and the correct AR...
In the 1024x576 encode instead, if i set a desktop resolution of 1024x768 (wich i set for movie playback in Media Player Classic) i get no resize at all, mantaining the 1024x576pixels untouched.
In this way i can control wich kind of resize (usually i prefer Lanczos via avisynth) is used to stretch the picture to get the correct AR during the encoding phase. There will be no more software/hardware resizes... and this results in a better overall picture quality.
Another point is at higher resolutions the artifacts will be less visible (coz 8x8 blocks will be smaller)...

[Soulhunter]

Think I should post this again...

http://img115.exs.cx/img115/6343/Source.th.png (http://img115.exs.cx/my.php?loc=img115&image=Source.png) http://img115.exs.cx/img115/7765/Result.th.png (http://img115.exs.cx/my.php?loc=img115&image=Result.png)


Bye

[PiXuS]

@Soulhunter

What do they represent? One is Source.png, the other Result.png... Result.png looks much more detailed... okay... interesting... but... what is the process you used? Or maybe you didn't say because you wanted someone to specifically ask? :)

[Skywalkerjen]

Thanks for the continued help:

Koepi: Size of the file is not a problem - I actually don't mind it going larger than the MPEG2 as I want it out of the MPEG2 format and into the MPEG4 for various reasons.
You've definitely set my mind straight about the first problem - I will resize and filter before encoding - so thanks for that.

SeeMoreDigital: Many thanks for the link - I've saved it for future reference too - good explantation. A further question though:

For Pal:

16:9 (1.77) 576 x 1.77 = 1024x576 for 16:9
4:3 (1.33) 576 x 1.33 = 768x576 for 4:3

What happens with letterbox? Is it the same as 16:9?
For PAL (after cropping the black bars), the picture is usually 288 vertical pixels.
1:2.5 (2.5) 576 x 2.5 = 1440 x 576 for Letterbox?

Sharktooth: Makes perfect sense - if I encode at 1024x576 and my desktop resolution is 1280x1024, there will be no resizing done on the XviD as long as I don't run in full screen?

SoulHunter - thanks for the photos - you can clearly make out the pock marks in Morpheous's face on the larger file - unless the bitrate is kept proportionally high, increasing the resolution will not make the picture clearer? I am using constant quant 2 so that will automatically match the bitrate with the resolution?

:cool:

[lemon]

Well, do what you want, but you will never gain anything from it.

It is a transformation, and you will ALWAYS loose quality on a transformation.
The best quality you can get is storing exactly the same resolution, so 720x480 if it is NTSC. What you can do is crop the black bars if there are, of course.

Every filter you must apply (as resizing, for example) can be done on playback, it should be no problem for a current computer, and less for a computer in five years... but there are always better algorithms, etc. so probably if you store it with maximum quality (no resizind nor filtering), you can get better visual aspect applying realtime filters when playing finve years from now that you would get if you apply this filters now and effectively ruin your sources for always.

[Didée]

Blah blah.

While it is fully correct that every single filtering step inherently looses information from the input source, you cannot draw a dogma out of that. Unless you prefer to make yourself a jester by insisting on that point of view.

In case you didn't notice, I'm not talking of quick'n'dirty resizing here, but of (agreed slow) image processing.

In the source there is not only useful information, there is also bogus information like noise, and other things that can hardly be reproduced anyways but that do confuse the encoder.

I'd say if I process a source, and in the end I've lost 1% detail, but at the same time reduced unrelevant information by 80% and increased compressability by 20%, then there is a "plus" standing under the line, not a "minus".

I'm a little short with public available samples ... look at this (http://forum.doom9.org/showthread.php?s=&postid=518035#post518035) and tell me how utterly bad it looks ;)

[Soulhunter]

@ Skywalkerjen

It shows that with the right filtering the result will look better than the source. The left picture shows how the source would look with normal fullscreen resizing, but the right picture was upsized with lanczos and enhanced with LimitedSharpen!


Originally posted by lemon

Every filter you must apply (as resizing, for example) can be done on playback, it should be no problem for a current computer, and less for a computer in five years...

Ehm, by the way... The processing Ive shown above runs @ 2fps with my Athlon XP3000+ And no, I dont wanna wait for 40GHz CPU's to filter the source realtime while playback... :D


Bye

[Skywalkerjen]

Lemon: Interesting point - I hadn't thought about future processing. However, if I can improve the source now the future processing will improve it even better.

Didée: You're still making perfect sense to me (you a teacher? - the video can be improved far more than the information lost in resizing etc. Thanks for monitoring the thread.

Soulhunter: Thanks for the information on the two pictures - definitely a difference and that's just what I'm after. Doing a search on LimitedSharpen now...

Any info about the letterbox aspect - is it just encoded as a 16:9 with black borders?

:cool:

[PiXuS]

@Soulhunter

Smode=?
Strength=?

@Skywalkerjen

Didée is 'da man. ;) I recommend you do a search for all the posts from Didée (http://forum.doom9.org/search.php?s=&action=showresults&searchid=958454&sortby=lastpost&sortorder=descending). You will learn a LOT from what he had/has to say...

[Soulhunter]

@ PiXuS

IIRC it was like this...

LimitedSharpen(2,2,1024,416,2,100)

But the 100h processing chain was a bit more complex... :D


Bye

[SeeMoreDigital]

Originally posted by Skywalkerjen
SeeMoreDigital: Many thanks for the link - I've saved it for future reference too - good explantation. A further question though:

For Pal:

16:9 (1.77) 576 x 1.77 = 1024x576 for 16:9
4:3 (1.33) 576 x 1.33 = 768x576 for 4:3

What happens with letterbox? Is it the same as 16:9?The black mattes that you see in a "letter-boxed" DVD movie, are part of the 720x480/576 anamorphic frame. In actual fact, the mattes could be considered as being "image" pixels too... that just happen to be black ;)

Originally posted by Skywalkerjen
For PAL (after cropping the black bars), the picture is usually 288 vertical pixels.
1:2.5 (2.5) 576 x 2.5 = 1440 x 576 for Letterbox? This all depends on the encoding tool you use. Some will attempt to resize the encoded frame "automatically". But, once you get used to your encoding applications settings, you might decide to enter/use your own settings.

If you refer to Soulhunters images, you will see that he has cropped away the black mattes while keeping all the original "moving video" pixels.... 1024 divided by 416 = 2.46:1 (which is as close as you can get to the movies AR of 2.40:1).


Cheers

[SeeMoreDigital]

Originally posted by Soulhunter
@ Skywalkerjen

With the right filtering the result will look better than the source imo !!!

The left picture shows how the source would look with normal fullscreen resizing...

But the right picture was upsized with lanczos and enhanced with LimitedSharpen !!! And if you buy a stand-alone player, with one of the new Sigma chip-sets, you'll be able to play your 1024x576 encodes and view them on your TV too!


Cheers

[Skywalkerjen]

SeeMoreDigital:

"The black mattes that you see in a "letter-boxed" DVD movie, are part of the 720x480/576 anamorphic frame. In actual fact, the mattes could be considered as being "image" pixels too... that just happen to be black"

So the letterbox is just 16:9 or even 4:3 and is resized as such - just requires cropping of the black bars?

[SeeMoreDigital]

Originally posted by Skywalkerjen
So the letterbox is just 16:9 or even 4:3 and is resized as such - just requires cropping of the black bars? You have to be careful here. Because not all wide-screen presentations (with mattes) are authored for use with 16:9 TV's. Some are authored specifically for use with 4:3 TV's.... such disc's are best avoided and are thankfully getting less common!


Cheers

[Skywalkerjen]

SeeMoreDigital: Right - I can use Gordian Knot to preview the letterbox movies and to check if they are in 4:3 or 16:9. Fantastic.

Many thanks to everyone who took the time today to answer my questions.

I've got all the information I require (that I can think of!) and am amazed at how quickly everything was answered. Much appreciated.

I certainly got my money's worth today!

Best wishes

Skywalkerjen:D

[lamer_de]

While I don't doubt that stuff that has been processed by iip does look better than the source, I doubt it's due to the increased resolution, but due to the sharpening/contrast enhancing/whatever else iip does. While I have not tested this myself, I guess if you would run iip to output the result at the same resolution as your input clip, it would look just as spectacular. After all, it gets resized during playback again, unless you happen to encode for your playback resolution (and well, i would guess DVDs just offer that resolution for TV playback). And while you might see the difference between bilinear and lanczos resizing in screenshots, at least I am not able to do so when watching the movie from a normal viewing distance and not 10cm away from my monitor spending half a minute comparing smallest details on freeze frames. So pre-processing: definitely positive, upsizing: questionable.

CU,
lamer_de

[LoKi128]

I just want to mention a couple of ideas I have about the whole anamorphic situation, and whether to un-anamoprh before resizing.

Originally, anamorphic compression was used to solve the simple problem of fitting a rectangular image into a square (exagerating here) film frame. It was just not practical to physically modify all of the machines used to process film, so filmmakers used lenses to better utilize the space in a frame. After all, it is better to compress the sides (or stretch the height) of an image than to let that unused space go to waste. This works quite well because of the very high resolution of film.

Nowadays, in DVDs, the only reason anamorphic compression is used is because for whatever reason, we cannot use just any frame size on MPEG2 encodes. We are artificially limited to whatever standards the powers-to-be have assigned, and therefore face the arcaic limits of physical media in a digital world.

HTDV is encumbered in this way as well, with fixed resolutions and framerates. I don't know enough about HD-DVD and Blu-ray, but I expect a similar situation.

As to whether I think that video should be anamorphed or not, it all comes down to pixels per frame. It is what determines the bitrate required for the video if we remove content considerations. If you shrink the sides of the image, you shrink the bitrate, but also the quality, since those pixes that you removed will never come back. They CAN be interpolated quite nicely by some resizing algos, though. The other option, to expand the vertial only creates artificial pixles and needlesly increases the bitrate without providing any extra detail.

So in summary, I believe that anamorphic distortions were/are a necessary evil in the physical media world, but should not be used with digital media that supports arbitrary resolutions.

[PiXuS]

Originally posted by LoKi128
So in summary, I believe that anamorphic distortions were/are a necessary evil in the physical media world, but should not be used with digital media that supports arbitrary resolutions.

Maybe this phrase should have ended with "...that supports arbitrary resolutions AND have an arbritrary capacity."

Has you had pointed in your post, if you encode directly to, say 1024x576, the file size of your video will be MUCH higher than the one @ 720x576.

Or maybe I missed your point...

[scharfis_brain]

please don't forget: 720x576 anamorphic equals to 1050x576

[SeeMoreDigital]

Originally posted by scharfis_brain
please don't forget: 720x576 anamorphic equals to 1050x576 ITU 601 and analogue displays - strikes again!

[scharfis_brain]

I know the 601.
or better said: crop to 704 or 702 then blow up to 1024.
analogue displays can't display anything outside 702, I know.

[PiXuS]

@SeeMoreDigital & scharfis_brain

Damn it scharfis_brain! I had specifically used the number 1024 instead of 1050 to make sure SeeMoreDigital wouldn't go on a chainsaw rampage again! :D

1024... 1050... whatever makes people happy...

[SeeMoreDigital]

Originally posted by scharfis_brain
I know the 601.
or better said: crop to 704 or 702 then blow up to 1024.
analogue displays can't display anything outside 702, I know. Yes and no!

Have you tried any of my 720x576 16:9 anamorphic "test cards" yet?


Cheers

[scharfis_brain]

okay, I'll set up a filter in my brain:
if (seemoredigital present) and (720 present) and (1024 present) then do not reply :)

[Sharktooth]

Originally posted by Skywalkerjen
Sharktooth: Makes perfect sense - if I encode at 1024x576 and my desktop resolution is 1280x1024, there will be no resizing done on the XviD as long as I don't run in full screen?
Yes, there will be no resize unless you go fullscreen. I usually like to watch movies in fullscreen btw...:)

[SeeMoreDigital]

The proof is in the viewing!

Try this PAL 16.9 "Test Card" (www.SeeMoreDigital.net/51_Test_Encodes/Test_Cards/PAL_16.9_Test_Card_-_720x576_with PAR@64.45_in_AVI.zip). It was encoded using 720x576 pixels with a PAR of 64:45.

Provided you have an Mpeg4 DSdec filter/player capable of handling PAR signalling, you should have no problems viewing the left and right edges of the encode, on both "analogue" CRT and LCD computer monitors.


Cheers

[Skywalkerjen]

Sorry guys - you are talking a little over my head here - how does 720x576 anamorphic equals to 1050x576?
Is 16:9 (1.77) 576 x 1.77 = 1024x576 incorrect (for PAL?)

[Sharktooth]

I always encoded @ 1024...

[SiXXGuNNZ]

these are always the calculations I have used

NTSC

16:9

RAW......: 720x480
Playback.: 864x480 = 1.78

4:3

RAW......: 720x480
Playback.: 720x540 = 1.33

PAL

16:9

RAW......: 720x576
Playback.: 1024x576 = 1.78

4:3

RAW......: 720x576
Playback.: 768x576 = 1.33

HD

Playback.: 1920x1080 = 1.78

[SeeMoreDigital]

Originally posted by Sharktooth
I always encoded @ 1024... So do I with some stuff...

The main problem with generating "square pixelled" encodes at 1024x576 was that you could not play them in stand-alones... Thankfully this situation has just (http://www.avsforum.com/avs-vb/showthread.php?s=&threadid=459759) started to change.

And to those of you with Mpeg4 DSdec filters/players capable of handling PAR signalling... Could you see the edges of my "Test Card"?


Cheers

[Sharktooth]

Originally posted by SeeMoreDigital
So do I with some stuff...

The main problem with generating "square pixelled" encodes at 1024x576 was that you could not play them in stand-alones... Thankfully this situation has just (http://www.avsforum.com/avs-vb/showthread.php?s=&threadid=459759) started to change.

And to those of you with Mpeg4 DSdec filters/players capable of handling PAR signalling... Could you see the edges of my "Test Card"?


Cheers
Well, my "standalone" is a modded xbox... so, no problems here :)
Regarding the "test card", yes i can see them.

[scharfis_brain]

hm.. I do not own a MP4 capable Standalone.
(maybe those devices are doing the 720 <-> 704 thing wrong?)

the EBU / ITU recommends (why a recommendation only?) 702 pixels for the active image area.
those 702 (seven-zero-two) pixels equals to 768 pixels for 4:3 and 1024 for anamorphic 16:9

that's exactly the PAR of 1.094 (768/702) for 4:3
or a PAR of 1.459 (1024/702) for anamorphic 16:9

720x576 is actually a little bit WIDER than true 4:3 (or 16:9):
720*1.094 = 788 for 4:3
720*1.459 = 1050 for anamorphic 16:9

seemoredigital uses a PAR of 1.0666 (768/720), which is called generic PAR and is sometimes present on DVD or DVB-broadcasts.

Also all Software MPEG-2 Decoders I know squeeze 720 and 704 to exactly the same width, what is definately wrong.
(720 is sqeezed by 1.066 and
704 gets sqeezed by 1.094 )
in MPC I use to press number 6 on the num-block once to achieve the correct AR with 720px DVDs.

But as I stated before: it is not the recommendation of the ITU/EBU to use generic PAR

but in the end it is up to you, what you are doing with your encodes.

some last words:
What are recommendations/rules for?
To break them! :rolleyes:

[Soulhunter]

Hmm, guess I understood this ITU recommendation wrong then!? I always thought they would recommend it coz TV's have this overscan area... So that the DVD producers should place a boarder at the left/right side, no?


Bye

[SeeMoreDigital]

Originally posted by scharfis_brain
hm.. I do not own a MP4 capable Standalone.
(maybe those devices are doing the 720 <-> 704 thing wrong?) They are not doing anything wrong... Neither are DVD player manufacturers!

More and more "digitised" content is being broadcast and encoded filling "all" 720 width pixels with image. And not just 702 or 704 pixels out of the available 720. This is especially the case with DVD content, as very few are encoded today with thin vertical black mattes, to the left and right of the image!

Nobody (not even me) is saying there's something wrong with the ITU standard. It's just that hardly anybody today is following it and it's getting less by the month!

I can only assume that there are a hell of a lot of people viewing DVD and DVB content via their PC monitors (including broadcasters and professional DVD authors). And that a lot of industry tech support guys (like me), got fed up explaining why the over-scan area was there (like me), and decided to dump it (also like me).

So... given that it seems more "industry people" are not following the ITU standard than are, maybe it's time for the ITU standard die hards to modify their views ;)


Cheers

[akupenguin]

Even if you assume that the overscan area is invisible, is there anything wrong with putting more video data there? I'm willing to bet that you can produce lower bitrate per quality by padding with a few more pixels of movie than by padding with black.

[SeeMoreDigital]

Originally posted by akupenguin
...Even if you assume that the overscan area is invisible, is there anything wrong with putting more video data there? The over-scan is only invisible when viewing via an analogue CRT TV screen ;)

Originally posted by akupenguin
...I'm willing to bet that you can produce lower bitrate per quality by padding with a few more pixels of movie than by padding with black. Actually no!

Encoding in black uses hardly any bitrate. However if the edge between the matte and the image is not "razer sharp", bits will be lost, because the codec finds such transition areas difficult to compress and encode!


Cheers

[akupenguin]

To efficiently encode the black edge, it needs to be more than razor sharp. It also needs to be aligned on a macroblock boundary.
Here's what happens to bitrate if the edge isn't aligned:
(This test was performed in MPEG4, but the same should apply to MPEG2 except that you don't get to use 4mv.)
(Also, this test just misaligned the right and bottom edges. I have to assume that the effect would be even greater if there are borders on all 4 sides, like many DVDs I've seen.)
http://students.washington.edu/lorenm/src/mplayer/lavc_tests/scale_graph1.s.png
http://students.washington.edu/lorenm/src/mplayer/lavc_tests/scale_graph2.s.png

[SeeMoreDigital]

If you have Blade Runner on DVD, run that thru' your tests? It has the worst example of horizontal and vertical mattes I've ever seen!

But in all honesty as long as the matte runs nicely along a line of pixels, you should be okay.

I wonder. Are there any tools out there that can introduce/overlay mattes to Mpeg4 encodes?


Cheers

[Manao]

Akupenguin : instead of padding yourself, let the codec do it. The norm specifies that, if the resolution isn't mod16, a padding shall occur in order to bring it to a full mod16 resolution.

[akupenguin]

@SeeMoreDigital:
I can't test how much you already lost if the source has borders. I can only add my own borders to a clean source.

@Manao:
I'm sorry, that's what I did (lavc padded it by repeating the border pixels, not with blackness. And 466x466+padding took 10% more bits per psnr than 480x480).
Which means my graphs are not exactly applicable to this discussion, since I was talking about black borders on DVDs, not about some padding is.
More data soon, when I run the explicit padding version.

[PiXuS]

Originally posted by SeeMoreDigital
If you have Blade Runner on DVD, run that thru' your tests? It has the worst example of horizontal and vertical mattes I've ever seen!

But in all honesty as long as the matte runs nicely along a line of pixels, you should be okay.

I wonder. Are there any tools out there that can introduce/overlay mattes to Mpeg4 encodes?


Cheers

You know there is a problem with Blade Runner when AutoCrop needs 5000 samples to stop changing idea about which Crop parameters should be used. When Deckard's has his dream about the Unicorn, the whole picture suddendly takes something like 40 pixels more on the right and then it is back to normal (normal=picture never stops moving around).

Blade Runner is indeed a terrible DVD (not the movie.. the transfer!).

Can't wait for the remaster to come out (but... I will not hold my breath!! (http://www.brmovie.com/BR_Special_Edition.htm))

[SeeMoreDigital]

Thanks for the Blade Runner update PiXuS... this is indeed a pisser. If ever there was a classic movie screaming to be re-mastered... this is it!

I have PAL and NTSC versions on DVD and both are equally as bad :( That said I have been able to generate quite a nice looking XviD encode, which is far easier on the eye than the Mpeg2/DVD :D


Cheers

[scharfis_brain]

I use deshaker with very low correction limits on such bad shaky transfers.
It helps a lot!

[Skywalkerjen]

scharfis_brain: Could you check my understanding and correct me as appropriate:

PAL DVD resolution is: 720x576. If these were square pixels they would give an aspect ratio of 1.25
However, the pixels are not square, so 720x576 is still 1.33.
When converting to square pixels in XviD, it doesn't matter what the resolution is as long as it is also 1.33.

You were saying that to convert this to XviD's square pixels, you would actually get 788x576 or 1050x576.
This isn't 1.33.

If PAL DVD is in 1.33 (even though the pixels aren't square) then surely using XviD square pixel resolution of 1.33 is correct - in other words 768x576?

[scharfis_brain]

@seemoredigital: I will now talk about the ITU recommendation.
not about the strange things sometimes seen in VOBs.

@Skywalkerjen:
I will round the values a little bit for better understanding:
704x576 is pure 4:3 (1.3333:1) or 16:9-anamorphic (1.77777:1)
720x576 is wider than 1.3333:1 or 1.77777:1
it is actually 1.368:1 or 1.824:1

so, if you want to create an 4:3 (1.333:1) XViD out of a 720x576 DVD, you need to crop it to 704x576 and than resize to lets say... 640x480 or something similar.

this means: multiply the 720 (or 704) with either 1.094 for 4:3 or 1.4587 for 16:9 anamorphic.

then you'll get the square-pixel-resolution.
from that point, do your further calculations.

[SeeMoreDigital]

Skywalkerjen,

Please read my "anamorphic" explanation.

What you must try and understand is that the pixels on every DVD are not designed to be viewed "square". They are designed to be viewed "anamorphically".

All DVD's contain DAR signalling, which means the images you see on your screen are "distorted" ie: they are "anamorphic".


Cheers

[Skywalkerjen]

Thanks for replying so fast again!

So for a PAL DVD, (and it's non-square pixels), 720x576 is NOT 4:3.
704x576 is 4:3.

If I resize it to XviD: 768x576 then it will be correct ONLY if I have first cropped the MPEG2 from 720 to 704?

If so, where does that leave me with Gordian Knot? I always crop 4:3 video at the sides (usually 8 each side) to get the Aspect Error down. Is this the 16 pixel reduction you are talking about?

Finally - if I am missing the point entirely - am I encoding at a bad aspect ratio, losing any video information or causing any problems for myself by encoding at 1024x576 for 16:9? In short, can I carry on as I was in ignorance?!
:D

[SeeMoreDigital]

Originally posted by Skywalkerjen
Thanks for replying so fast again!

So for a PAL DVD, (and it's non-square pixels), 720x576 is NOT 4:3.
704x576 is 4:3. You are getting confused. Both will offer 4:3 images if the correct PAR or DAR signalling is used.


How are you intending to view your encodes Skywalkerjen?

What you must take into account is that scharfis_brain's "ITU standards" only come into effect if you're intending to view your encodes on an analogue CRT TV... But even then, they will most likely, not match your source.

Like I've said before... I have nothing against the "ITU standards"... they just don't work very well if your intention is to match your source. ie: when generating 1:1 encodes from Mpeg2 DVD, DVD or DV sources.


Cheers

[Skywalkerjen]

I was planning on building a PC XviD jukebox - storing all the XviDs on some huge hard discs and then playing them through the TV output on a graphics card (using media player classic).

Their final destination would be a 28in 4:3 PAL TV.

EDIT: Although I hope to use these XviDs in 15-20 years so HDTV / projector maybe in the future?

[Soulhunter]

Well, I simply ignore the ITU recommendation and use a resolution of 1024x576 !!!

For playback @ the TV I gonna use ZoomPlayer to match the overscan area...


Bye

[Skywalkerjen]

Right - so what am I actually losing by using 768x576 or 1024x576?
Is the TV cropping some of the image, or is there aspect error when watching through the TV?

[SeeMoreDigital]

Originally posted by Skywalkerjen
Right - so what am I actually losing by using 768x576 or 1024x576?
Is the TV cropping some of the image, or is there aspect error when watching through the TV? Nothing at all.

As scharfis_brain has already pointed out, conventional CRT TV's can't display the entire 720x576 image area, they are much happier with an 702/704 image area! However, you'll be hard pressed to find a store bought DVD that's been encoded with 704x576 pixels as they all use 720x576 pixels. And most have been authored to use all 720 width-ways pixels too (which indeed breaks the ITU standard).

If you are intending to view your encodes on an CRT TV, then by all means follow the ITU recommendations.

But ask youself...

At the end of the day, if your "anamorphic" 720x576 Mpeg2/DVD source (with DAR signalling), looks like this: -

http://img114.exs.cx/img114/8708/007201024x576Source.jpg


Do you want your Mpeg4 encode to look like this: -

http://img114.exs.cx/img114/6959/017201024x576Encode.jpg


Or, do you want it to look like this (note the vertical black bars to the left and right of the image): -

http://img97.exs.cx/img97/3510/027041024x576Encode.jpg

Both anamorphic Mpeg4 encodes will look fine on a TV. But only the middle image "exactly" matches the source. Which you'll plainly be able to see if you viewed it via an analogue CRT/LCD computer monitor or digital monitor...


Cheers

[Skywalkerjen]

Many thanks for posting the screenshots SeeMoreDigital.

As you said - the TV image will look fine either way - you won't see the black borders on the left and right side for either way.
However, the XviD won't look the same on a computer monitor as it has been cropped to remove information the TV can't display.

As I am hoping to use the XviDs for many years - and therefore have no idea what I'll be viewing them on then (but it'll probably be digital), I'll keep the XviDs as close to the source as possible.

EDIT: PLEASE tell me I've got this bit right!

[SeeMoreDigital]

Originally posted by Skywalkerjen
As you said - the TV image will look fine either way - you won't see the black borders on the left and right side for either way. Correct.

Originally posted by Skywalkerjen
However, the XviD won't look the same on a computer monitor as it has been cropped to remove information the TV can't display. Neither of the encoded images have been cropped. The bottom image has been resized.

And just to make clear... If you install and use MPEG4 Modifier, you can add or amend PAR signalling any type of Mpeg4 video stream (ie: XviD, 3ivx, NeroDigital, DivX, FFmpeg etc.

Originally posted by Skywalkerjen
As I am hoping to use the XviD's for many years - and therefore have no idea what I'll be viewing them on then (but it'll probably be digital), I'll keep the XviDs as close to the source as possible. I have analogue CRT and LCD screens. I also have a 42" 1280x768 plasma screen which is connected via DVI (ie: digital) and via analogue VGA and component inputs... Which is how I know why the encodes can look different!


Cheers

[scharfis_brain]

there are also sources that have the overscan borders filled with image information (like DV-Video)
but its true PAR is 1.094

some time ago I had a conversation with a german forums member about exactly this issue:
"which PAR is used on commercial DVD?"

he said, he measured a lot of sources (DVD) for their real PAR.
he usually took circles or general, well known used images to measure the real PAR.

his conclusion was, that more DVDs are fitting the ITU.
(even if the border was filled with image information)
some were generic PAR (as seemoredigital suggests to use).
and others had a PAR ranging between generic PAR and ITU-PAR.

So my conclusion is: it is not a key sign if the overscan borders are filled, that a generic PAR was used by the producer.
that's why I am always going safe and resize or display my video ITU-conform, as every SAP/TV does and every Software-Player *SHOULD* :rolleyes: do.


btw.:
All DVDs, I encoded so far are 704x576.
(they are mostly analogue caps or DV-Video with heavy filtering applied for fitting some visual aspects)
IMO this is the safest method - AR wise - to create a DVD.
No possibilities to get in confusion with 704x576 sized DVDs

btw2nd:
on your site one can read this:

"And technically, because NTSC TV's typically operate at 60Hz (to match the incoming electricity supply frequency), which is not a multiple of 29,97fps, there will always be a negligible amount of jerkiness during video playback."

do you mean a slight off between 60Hz and 59.94 Hz?
TVs aren't synced anymore by the powergrid. they are synced by the video-impulses. so no 1.001-jitter at all...

[Skywalkerjen]

Thanks for th4e replies guys.
Pretty much all of it is way over my head - if I just resize to 768x576 or 1024x576 then it will still look fine on the TV AND on digital displays then I will go ahead. (Also this is after cropping the black borders, which I hope doesn't set us back to square one!)

A more general question: Why the obscure numbers in video - is it like the VHS/Beta where the most popular became the standard? It just seems there are a lot of numbers in the standards that are not easily divisible...:cool:

[SeeMoreDigital]

Originally posted by scharfis_brain
there are also sources that have the overscan borders filled with image information (like DV-Video)
but its true PAR is 1.094 We are not discussing the topic of DV video to Mpeg4 encoding in this thread.

Originally posted by scharfis_brain
some time ago I had a conversation with a german forums member about exactly this issue:
"which PAR is used on commercial DVD?"

he said, he measured a lot of sources (DVD) for their real PAR.
he usually took circles or general, well known used images to measure the real PAR.

his conclusion was, that more DVDs are fitting the ITU.
(even if the border was filled with image information)
some were generic PAR (as seemoredigital suggests to use).
and others had a PAR ranging between generic PAR and ITU-PAR. Fine that's "his" conclusion.

But without knowing the exact Mpeg2/DVD sources he tested it's impossible to pass a positive or negative comment....

Originally posted by scharfis_brain
So my conclusion is: it is not a key sign if the overscan borders are filled, that a generic PAR was used by the producer.
that's why I am always going safe and resize or display my video ITU-conform, as every SAP/TV does and every Software-Player *SHOULD* :rolleyes: do. I would suggest you spin a few of your "store bought" PAL 1.851 and 2.35: DVD titles, take some still captures and make your own assessment.

In my experience many pre 2002 1.85:1 sources followed the ITU standard than 2.35:1 sources. However, in post 2002 and most certainly in 2004, more 1.85:1 and 2.35:1 DVD sources don't follow the ITU standard.

Here's an 720x576 anamorphic capture of Shrek 2 (1.85:1) for example: -

http://img56.exs.cx/img56/1153/Shrek2.jpg

I don't know about you... but I can't see any over-scan area here?


Cheers

[Sharktooth]

ITU standard is old and outdated.
Newest DVDs does not follow ITU at all.

[Skywalkerjen]

If some DVDs are actually 704x576 and the pixels aspect ratio is such that this is 4:3 aspect ratio, then if I convert this to XviD (and it's square pixels), as long as I keep it in 4:3 ratio, such as 640x480 or 768x576 it should be OK.

As 1050x576 isn't 4:3 for XviD - are you saying that this should have vertical black bars, or a different PAR?

Am I getting close?!

[SeeMoreDigital]

Originally posted by Skywalkerjen
If some DVDs are actually 704x576 and the pixels aspect ratio is such that this is 4:3 aspect ratio, then if I convert this to XviD (and it's square pixels), as long as I keep it in 4:3 ratio, such as 640x480 or 768x576 it should be OK. As I've said before... You wont ever find a "store bought" DVD encoded with 704x480 or 704x576 pixels. They are all 720x480 or 720x576!


;)

[2Bdecided]

Thanks for an interesting thread people!

On the subject of standard analogue CRT TVs, they don't display anything near 704x576 - typical overscan is usually quoted as 10%. I've tried resizing a 4:3 source down into a 10% smaller 4:3 window (5% black bar along each picture edge), and you can just start to see black bars on some sides of some TVs - but by no means all. It's no wonder the industry uses a 10% frame to define the "action safe" area, and ensures that captions etc are within the 20% "title safe" area.

IIRC it's 702x576 that's 4:3. The extra 18 pixels were included for historical reasons - otherwise any timing inaccuracies would cause active picture to be lost going from analogue>digital, and an unwanted step response would lie right on the edge of active picture. If you go analogue/digital/analogue a few times (quite likely with digital processing in the analogue world) you could make quite a mess of the edges - so extra pixels were included to catch that.

Many digital sources put picture information right out to 720. There's nothing wrong with that. What is wrong (but, to be bluntly honest, almost irrelevant to most viewers) is assuming that 720x576 is 4:3.

However, the presence or absence of information in those extra 18 or so pixels doesn't prove the aspect ratio - you could preserve the extra information from the film print in this region while still making the centre 702x576 match 4:3 (film prints aren't usually projected to the edge either, so there's probably a little extra to grab if you want), or you could scan the film print in to make 720x576=4:3 (incorrectly) - both would light up all the pixels.

Conversely, you could have something (wrongly) digitised at 720x576=4:3, then send it through some process (e.g. digital>analogue>digital) which strips the extra side pixels, meaning you don't even have all the original 4:3 data! It would look like 702x576 should be 4:3 (because the extra 18 or so pixels are black), but actually the aspect ratio is 720x576=4:3 with some of the picture missing!

btw (and no-one ever believe this, but it's true) when you use an LCD display as a TV (i.e. you buy something called a "TV" which uses LCD display technology) it will still have overscan. Not (usually) as much as your average CRT TV, but some. Switch it to PC mode, and it'll have none.

Last point: while you can make images look nicer by pre-processing and pre-resampling them, if something better comes along in the future, you'll have to re-encode. If you make a good job of encoding the original resolution, you can take advantage of any advances in post-processing without re-encoding the source. But then, if you didn't like encoding things, you wouldn't be reading doom9, would you? ;-)

Cheers,
David.

P.S. every time I wrote "4:3" of course you could replace it with "16:9" and it would still be true.

P.P.S. which remind me - watch a 4:3 source in the correct aspect ratio on a 16:9 TV, and the TV will still blank part of the picture that a traditional 4:3 TV would hide in the overscan. However, watch 16:9 content letterboxed to 4:3 by a STB or DVD player, and you'll only lose a few lines - much less than would be hidden by overscan on a 16:9 TV.

[scharfis_brain]

@seemoredigital:
the two DVDs I currently have here are both with ITU-fitting AR.

"They live" 1988
"Die purpurnen Fluesse / Les rivieres poupres" 2002

I suggest you to post a sample image again of that shrek-DVD.
but this time from the very end.
especially a frame where the dolby/THX (or so) Logos appear.

those logos are well know regarding their look, which also means their AR is known, too!

only given this image we can judge, whether your shrek-DVD is ITU-PAR or generic-PAR.
the missing overscan-borders aren't a sign for generic-PAR, as I stated before.

@2Bdecided: I always thought I was alone with my point of view. but now I am no longer alone :)

[Skywalkerjen]

Thanks for your post 2Bdecided.

As you can tell I haven't got a clue what these guys are talking about - if they say encoding at 768x576 or 1024x576 then that's fine with me!

About your last point though:

"while you can make images look nicer by pre-processing and pre-resampling them, if something better comes along in the future, you'll have to re-encode. If you make a good job of encoding the original resolution, you can take advantage of any advances in post-processing without re-encoding the source."

If I just resize using Lanczos without any other preprocessing, what problems may I have in the future regarding realtime post-processing. Are future post-processing algorithms going to require the original resolution or should they work equally well on the enlarged XviDs?

[Soulhunter]

Originally posted by scharfis_brain

I suggest you to post a sample image again of that shrek-DVD.
but this time from the very end.
especially a frame where the dolby/THX (or so) Logos appear.

those logos are well know regarding their look, which also means their AR is known, too!

only given this image we can judge, whether your shrek-DVD is ITU-PAR or generic-PAR.
the missing overscan-borders aren't a sign for generic-PAR, as I stated before.

But this intros/logos are done separately from the main movie afaik, no?

I mean, the intro could have a complete different AR/PAR... :\


Bye

[scharfis_brain]

I am talking about the logos at the very end of the scrolling end-titles.
Those ones are embedded in the film itself. So I doubt they are different PAR than the movie.

[SeeMoreDigital]

Originally posted by scharfis_brain
the two DVDs I currently have here are both with ITU-fitting AR.

"They live" 1988
"Die purpurnen Fluesse / Les rivieres poupres" 2002.What are the aspect ratios of these movies AR. How about looking at newer DVD titles?

Originally posted by scharfis_brain
I suggest you to post a sample image again of that shrek-DVD.
but this time from the very end.
especially a frame where the dolby/THX (or so) Logos appear.

those logos are well know regarding their look, which also means their AR is known, too!

only given this image we can judge, whether your shrek-DVD is ITU-PAR or generic-PARActually, it would be irrelevant to do this because the "THX Logo" is not part of the main movie. And in all likely-hood, will bare no relation to the "main movie" - which is after-all what we want to encode!

Originally posted by scharfis_brain
the missing overscan-borders aren't a sign for generic-PAR, as I stated before. It is however a very good indicator!


Cheers

[Soulhunter]

Originally posted by scharfis_brain

I am talking about the logos at the very end of the scrolling end-titles.

Ah! Sorry then, seems I understood ya post wrong... ^^;

Btw, I guess eyes are a good way to check the AR, pupil/iris should be perfect round, no?


Bye

[SeeMoreDigital]

Okay... after reading the post you directed to Soulhunter... Is this what you are talking about: -

http://img61.exs.cx/img61/2433/Shrek_2_endtitles.png

And...

After re-sizing the anamorphic 720x576 source to 1024x576. And then cutting out the "Motion Picture Association of America" logo from the frame. I think you'll agree the circles look as round as they'll ever get: -

http://img79.exs.cx/img79/5351/Logo_cut-out.png


Cheers

[scharfis_brain]

thanks!

I've took this image and reiszed it both to
1024x576 (generic PAR)
and
1050x576 (ITU PAR)

then I measure the inner diameter of the logo you showed.

1024px sized image:
width=74 pixels
height=77 pixels

-> NOT an exact circle


1050px sized image
width=76 pixel
height=77 pixel

-> more round than before.

my conclusion: this source should be ITU-PAR.

but I'll look at the other Logos as well.

this was just a quick measurement.
my values 'could' be total crap,
so please redo it yourself for confirmation or disprovement.
I measured them using irfanviews marking-rectangle and a 200% zoom.

[akupenguin]

I agree with Scharfis on this point.
But I have run the same measurement on other movies, and found that some actually wanted 720x480->16:9.

[Soulhunter]

Hmm, with 1024x576 I get 76/74 for the big circle!

But I get exactly 20/20 for the 4 smaller ones...



Bye

[akupenguin]

The difference between 720 and 702 is only 2.6%. A 76 pixel circle is just barely enough to tell the difference, 20 pixels is not.

[scharfis_brain]

@soulhunter: the minimum feature-size to measure the 720/702 thing cannot be smaller than around 40 pixels, cause if going lower in size, the deviation of 702/720 is smaller than a whole pixel. that's why the small circles are 'exactly' 20x20.

720/702 = 40/39 = 40/(40-1)

-> a 40 pixel sized object deviates by one pixel if improperly scaled.

[Soulhunter]

Yeah, makes sense...

Well, back to my previous idea!

We need a movie with a big frontal close-up of a human eye... :D


Bye

[scharfis_brain]

@soulhunter: hm.. "minority report" it also has a lots of round objects, called spheres (or is 'balls' better here?), in it...

@akupenguin:
I agree with Scharfis on this point.
But I have run the same measurement on other movies, and found that some actually wanted 720x480->16:9.

I never doubted this.
As I said before: A german member also measured a lot of DVDs concerning this issue.

[SeeMoreDigital]

I agree there is a difference. When I conducted my own calculations...

The 1024x576 frame generated an 75x77 circle: -

http://img57.exs.cx/img57/3471/From_the_1024_capture_75x77.png

And, yes the 1050x576 frame generated an 76x77 circle: -

http://img66.exs.cx/img66/6831/From_the_1050_capture_76x77.png

But in my opinion this discrepancy is too small to make any visual difference!

But you still can't argue that this particular DVD (along with most of todays DVD's) has been encoded using all 720 pixels and not 704 or 702.


Cheers

[scharfis_brain]

But you still can't argue that this particular DVD (along with most of todays DVD's) has been encoded using all 720 pixels and not 704 or 702.

All I want to say is, that the PAR is 1.094 and not 1.0666

I do not feel irritated by missing black borders or so...
if there aren't any I just don't crop them, but I always use ITU-PAR.



it just means, your shrek has an DAR of:
1050x552 = 1.902:1

instead of

1024x552 = 1.855:1

in the end, one has to decide individually whether to use generic PAR or ITU PAR.

So I say: go for ITU. It is the safe way.

[Skywalkerjen]

I'm sorry for putting up the newb questions here - but where does this leave me with my XviD encodes?

Should I be using a different pixel aspect ratio to normal if I am using 1024x576 - our is it as SeeMoreDigital suggests - not a large enough difference to worry about?

If possible put it in laymans terms for my situation!!!

[PiXuS]

Originally posted by SeeMoreDigital
But you still can't argue that this particular DVD (along with most of todays DVD's) has been encoded using all 720 pixels and not 704 or 702.

I think you completely missed scharfis_brain's point. He had specifically said that the fact most DVD's nowadays use 720 pixels and not 70[24] doesn't mean they are not following the ITU standard.

I believe you just proved Shrek 2 is following the ITU standard! (unless, of course, the generic is different from the movie, but how probable is that?!)



@Skywalkerjen

my goal is not to be rude, but your questions are rather... redundant. Did you try to do some research on the subject? There is this sticky (http://forum.doom9.org/showthread.php?s=&threadid=42708) which might help. Otherwise, there is a guide on doom9.org on the subject. Also, this subject has come up more than once... if you search on the forum you WILL find information.

[SeeMoreDigital]

Just to keep Soulhunter happy, here's a still of an eye: -

http://img104.exs.cx/img104/9404/Eye.png

This frame is 720x576. And the image are works out at 704x576, which should keep scharfis_brain happy.

Unfortunately a human eye is not a good enough circle anyway. Because where the sclera (the white bit) meets the iris (the coloured bit) is not perfectly round.

And how do I know this... becuase my grandfather created the worlds first "plastic" eye :D


Cheers

[SeeMoreDigital]

Originally posted by PiXuS
I think you completely missed scharfis_brain's point. He had specifically said that the fact most DVD's nowadays use 720 pixels and not 70[24] doesn't mean they are not following the ITU standard. If all DVD's followed the standard. They would be encoded using 704x576 "active" pixels within an 720x576 anamorphic frame... Like the above still!

Now if somebody want's to post a still from an "ITU standard" anamorphically encoded Mpeg4 frame, please do so!

How many pixels are you going to use. 704, 720?

And what PAR signalling are you going to use?

And what will your software player identify the PAR frame as being?


Cheers

[Skywalkerjen]

PiXus:

"@Skywalkerjen

my goal is not to be rude, but your questions are rather... redundant. Did you try to do some research on the subject? There is this sticky which might help. Otherwise, there is a guide on doom9.org on the subject. Also, this subject has come up more than once... if you search on the forum you WILL find information."

Thanks very much for the link. I am sure my questions are becoming redundant - they haven't been answered particularly well - that's why I continue to ask the same questions. I'm no expert after all.
I was expecting at some point to be told to search the forum (which I have) but I appreciate all the replies from SeeMoreDigital, SoulHunter and Scharf's Brain.

Should I be using different forum for these questions? I get the impression that Doom9 forum is where the experts hang out - that's why I'm here, but I also get the impression that some members have little time for newbs such as I. That's absolutely fine by me and I certainly don't want to waste anyones time. Just trying to make sense of what I am doing as it is taking a lot of my time and I don't want to make any stupid mistakes.:cool:

[Soulhunter]

Originally posted by SeeMoreDigital

And how do I know this... becuase my grandfather created the worlds firts "plastic" eye :D

Huh, seriously ???

Amazing... :eek:


Bye

[SeeMoreDigital]

Originally posted by Soulhunter
Huh, seriously ???

Amazing... :eek: Yep,

He worked out how to do it between the WW1 and WW2. He even appeared on the BBC (in 1939, just before TV transmissions in the UK ceased) blowing "glass eyes".


Cheers

[bleo]

It seems that there could be three different PARs used by DVD makers. I don't want to say that one is universally correct. I suppose you could be really anal about it and visually scrutinise circles to find out which PAR to use when reencoding each DVD... So here are some of the calculations I have done:

PAL
1. 'Generic' PAR: the whole 720x576 defines a 4:3 frame
4:3 PAR = 4/3 x 576/720 = 16/15 = 1.06 (where the underline denotes recurring digits)
and for 16:9, PAR = 64/45 = 1.42

2. 'DV' PAR: the middle 704x576 defines the frame
4:3 PAR = 12/11 = 1.09
16:9 PAR = 16/11 = 1.45

3. 'ITU' PAR: the middle 702x576 defines the frame
4:3 PAR = 128/117 = 1.094017
16:9 PAR = 512/351 = 1.458689

NTSC
1. generic, 4:3 PAR = 8/9 = 0.8, 16:9 PAR = 32/27 = 1.185
2. DV, 4:3 PAR = 10/11 = 0.90, 16:9 PAR = 40/33 = 1.21
3. ITU, 4:3 PAR = 320/351 = 0.911680, 16:9 PAR = 1280/1053 = 1.216...

Don't ask me which DVDs use which PAR! :p I find it easier just to use the PAR that is most convenient for your encoder. For example, xvid and WMV have PAR presets that follow the DV method. In anamorphic RealVideo you define the display resolution in pixels so for PAL, it's easiest to use the generic method and encode at 768x576 or 1024x576. Of course, xvid and WMV allow you to set custom PAR, so you may use whichever method you wish using the fractions I have calculated!

[edit] NTSC ITU 16:9 PAR fixed. Thanks scharfis_brain.

[LoKi128]

Quick Q... when I transfer from DVD to whatever, I usually load the play the movie using PowerDVD, select a bright frame, capture that, measure the image (and also the cropping i'm going to use, if any) and using those measurements figure out the AR. It almost never comes out to be 4:3 or 16:9 exactly.

Am I doing it wrong? Where does PowerDVD get it's AR data? I assume its embedded into the VOB or whatever. Is it more accurate to go with whatever the box says the AR is or with the measured value?

[bleo]

you guys who crop/resize/convert to square pixels/etc are making it more complicated for yourselves :p

anyway...
@LoKi128
The 'bright frame', especially after you crop, does not come out as 4:3 or 16:9 because the original film/source did not have that exact aspect ratio, or something happened to the edge of the image during transfer to DVD. But like I said, since you appear to be cropping and resizing to convert to square pixels, the calculations are a bit hard to explain. :p So my short answer is: "go with the measured value"

btw, I think PowerDVD uses the 'generic' PAR method... :)

[scharfis_brain]

you guys who crop/resize/convert to square pixels/etc are making it more complicated for yourselves

That's right, indeed.
But it helps understanding things better.

btw, I think PowerDVD uses the 'generic' PAR method...

Every Software MPEG-2 player displays wrong AR with 720 or 480 pixels wide sources. Even MPC with its internal filters

Are you sure, that DV and ITU PAR aren't the same?
(Any literature for that?)
I would say, that they are the same.

but your calculations of PARs are off!

16:9 PAR = 4:3 PAR * 1.333333

example ITU NTSC:
active analogue image area: 711x486
normed to digitised pixels: 702x480 (remember the 702, do you?)
ITU-PAR: 640/702 = 0.911... for 4:3
ITU-PAR: 853/702 = 1.215... for 16:9
1.215 : 0.911 = a factor of 1.333 => as I said :)

so there is some error with 1.108...

[SeeMoreDigital]

Originally posted by bleo
you guys who crop/resize/convert to square pixels/etc are making it more complicated for yourselves :p

btw, I think PowerDVD uses the 'generic' PAR method... :) Not at all... in many ways, it makes more sense!

For instance. In most software players, when you play Mpeg2 streams that have been ripped from a DVD, the files "video size" will be displayed as being this: -

http://img56.exs.cx/img56/162/ShowTimePlayer_Source_Info.png

Or this: -

http://img56.exs.cx/img56/591/MPC_Source_Info.png

If the ITU standard was being correctly adopted via software players, the video size should be reported as being 1050x576!

So if it's good enough for the software players to display the Mpeg2 source like this... it should be good enough for us all to encode it like this also.

Besides... it makes no logical sense to resize an Mpeg2/DVD's 720 image (with edge to edge active pixels) down to 704 prior to encoding, this would surely reduce image quality. Meaning the encode can't be considered as being truly 1:1. (It would be more like 1:0.97777 or 1:1.0227).

Making a true 1:1 back-up (from any source) should mean "no re-sizing" should take place.

Once the "pixel for pixel" (1:1) Mpeg4 encode has been generated, PAR or DAR signalling can be introduced.

And in my opinion, the PAR "numeric values" need to be looked at in more detail. Because if you generate encodes using the standard ITU values, the encodes pixel positions do not exactly match the source :eek:

It really is as simple as that!

[Didée]

SMD, your post reminded me of just another question:

Say we're going to do a straightforward 1:1 conversion without any resizing, probably at high bitrate. In that case, is it better to keep the source block-aligned, or is perhaps even the opposite true?

E.g. in the current XviD custom matrix comparison, Soulhunter is feeding a source with crop( 6, 76, 704, 432). This is not block-aligned (and the encoding is not really high bitrate).

Problem (or not) :

IF we keep the source block-aligned, then any mpeg-4 codec using 4mv will, most probably, result in ME decisions that refer to the 16x16 macroblocks of the mpeg-2 source, and will benefit only little from the m4v.
If the source is shifted away from being block aligned, then the codec has a better chance to do "free" decisions, and can benefit more from the 4mv search, as opposed to be forcely tied to the original block grid. However, coding probably will be a little more "costly" in the not-aligned case.

For medium bitrates, I'd definetly go for block alignment (and so I think the source in the matrix comparison is prepared suboptimally, especially since zero filtering is used).
But for higher bitrates, I can't say which of both is the better deal.

What's the answer to this? Is there even one?

[SeeMoreDigital]

Originally posted by Didée
SMD, your post reminded me of just another question:

Say we're going to do a straightforward 1:1 conversion without any resizing, probably at high bitrate. In that case, is it better to keep the source block-aligned, or is perhaps even the opposite true?

Problem (or not) I would have thought anything that involves shuffling the pixels over a bit prior to encoding has got to generate less efficient results, especially when the pixels are analysed in blocks of 16...

...but your question would be best answered by somebody with greater knowledge of macro block prediction than me.


cheers

[akupenguin]

Originally posted by Didée
If we keep the source block-aligned, then any mpeg-4 codec using 4mv will, most probably, result in ME decisions that refer to the 16x16 macroblocks of the mpeg-2 source, and will benefit only little from the m4v.
If the source is shifted away from being block aligned, then the codec has a better chance to do "free" decisions, and can benefit more from the 4mv search, as opposed to be forcely tied to the original block grid. However, coding probably will be a little more "costly" in the not-aligned case.
(Disclaimer: I haven't run any scientific tests of this, but I understand the theory well enough to venture a guess.)
Sure, the non-aligned case would use 4mv more often. But that's only because you made the 16x16 blocks less efficient. It wouldn't improve the efficiency of 8x8 blocks, so you wouldn't gain any PSNR.
The only possible gain would be psychological, by introducing all new blocking artifacts instead of exaggerating existing artifacts. And I think that could only help if you're playing it back without postprocessing.
But even for a 1:1 rip, you should still use some post-processing when decoding the DVD, and I don't know how that would affect the relative efficiencies.
And you have to consider: Is the gain from using an aligned source worth the cost of cropping to mod16 on all edges or leaving black borders? I can't answer that without testing.

[scharfis_brain]

what is 4mv ?!?

[bleo]

@scharfis_brain & SeeMoreDigital
Sure all software MPEG2 players use 'generic' PAR, and I don't blame them because it makes the resizing much easier, and results in a convenient 1024 display. :)

scharfis_brain: Are you sure, that DV and ITU PAR aren't the same? (Any literature for that?) I would say, that they are the same.

I just made up the name DV; it doesn't refer to any standard :p. But if you look in xvid and WMV, you will see that the preset PARs for anamorphic encoding use this method.

SeeMoreDigital: Besides... it makes no logical sense to resize an Mpeg2/DVD's 720 image (with edge to edge active pixels) down to 704 prior to encoding

Actually, to follow the DV method, you would CROP down to 704 (regardless of whether the edges have active pixels or not) then resize up to (exactly) 1024 pixels. Or if you wanted to keep the full 720 pixels, you would have to resize up to 1047.27 rounded up to 1048. So once again, things get complicated :p

Anyway, my recommendation is to encode anamorphically using PAR flags: (which vaguely brings us back to the original topic of this thread... :p)
1. Keep the original resolution of the DVD and do not resize.
2. You may crop off any black bars or noisy edges if you wish.
3. Set the PAR in xvid or WMV to whichever method you prefer. In fact, since it is just a flag it should be easy to change even after you encode.
4. That's it! No messy calculations!

btw, there is a THX test on the Star Wars DVD that has circles to test anamorphic encoding...

[darkavatar1470]

After some hard searching, I found a page that explains almost everything, and is the only one that actually tell you how to calculate 702/704 active pixels from the spec.--which I blew my head off trying...

http://www.uwasa.fi/~f76998/video/conversion/#3.2.1

and after some circle drawing,
i found out that my current project (NTSC 16:9) should be cropped to 704 or use a PAR of 40:33...
but i'd like to keep the extra horz. and encode full screen at 1024x564

[SeeMoreDigital]

Originally posted by bleo
Actually, to follow the DV method, you would CROP down to 704 (regardless of whether the edges have active pixels or not) then resize up to (exactly) 1024 pixels. Or if you wanted to keep the full 720 pixels, you would have to resize up to 1047.27 rounded up to 1048. So once again, things get complicated :pActually the correct method would be to crop the image area down to 704 and put it within a 720x576 frame. And introduce DAR signalling. Which is how it "should" be done on DVD and DVB... but more often than not you'll only see 704 laid over 720 when viewing 4:3 transfers and DVB broadcasts. You can see this method being used everyday when viewing Sky News.

Originally posted by bleo
Anyway, my recommendation is to encode anamorphically using PAR flags: (which vaguely brings us back to the original topic of this thread... :p)
1. Keep the original resolution of the DVD and do not resize.
2. You may crop off any black bars or noisy edges if you wish.
3. Set the PAR in xvid or WMV to whichever method you prefer. In fact, since it is just a flag it should be easy to change even after you encode.
4. That's it! No messy calculations!Try using the DAR flags instead of the PAR ones

Originally posted by bleo
btw, there is a THX test on the Star Wars DVD that has circles to test anamorphic encoding... This is very true.

Unfortunately, because the backgrounds of both the 4:3 and 16:9 "circle" samples are black, it's impossible to tell if they've been encoded as "704 laid over 720".


Cheers

[bleo]

@SeeMoreDigital
I think you've missed my point. I'm not concerned about whether or not the edge of the image has black or active pixels, or whether this indicates ITU compliance. This would only be important for display on TVs.

I only use the ITU word to denote its method for defining PAR. Its relevance is that when viewing an encode on a computer, you must use the PAR to convert to square pixels. This is done by either:
1. applying the PAR to the source by resizing, then encoding in square pixels; or
2. encoding the source anamorpically using PAR signalling, then resizing on playback.

Each of the three PAR methods I have defined will result in different images. The ITU method will look fatter than the DV method, which looks fatter than the generic method.

For example, a 720x576 PAL 16:9 DVD resized using the generic method will be 1024x576, DV method: 1048x576 and ITU: 1050x576 (or proportional to these, without regards to cropping). You can try this with the circles in the THX test to determine which method is correct for those DVDs.

SeeMoreDigital: Try using the DAR flags instead of the PAR ones

As far as I know, WMV doesn't use DAR flags, and in xvid, even though you may set DAR, I think it converts and stores it as PAR.

[Sagittaire]

Metric test for 1280*720 screen ...

Source: Video HD-WMV 720p from M$ Amazon_720.wmv

Video 1: 1280*720 encoding with q2 MPEG4 ASP. Bitrate ~6000 Kbps.

clip = DirectShowSource(Source)
clip = Lanczos4Resize( clip, 720, 576)
clip = Lanczos4Resize( clip, 1280, 720)
Return clip

Video 2: 720*576 encoding with q2 MPEG4 ASP. Bitrate ~4000 Kbps.

clip = DirectShowSource(Source)
clip = Lanczos4Resize( clip, 720, 576)
Return clip

Video 3: 1280*720 encoding with q3 MPEG4 ASP. Bitrate ~4000 Kbps.

clip = DirectShowSource(Source)
clip = Lanczos4Resize( clip, 720, 576)
clip = Lanczos4Resize( clip, 1280, 720)
Return clip


Source DVD 576p vs q2 720p encoding

Playing simulation of 576p DVD on 720p screen : SSIM = 90.11

# --> Video Opening <--

source = DirectShowSource("Amazon_720.wmv")

video = DirectShowSource("Amazon_720.wmv")
video = Lanczos4Resize( video, 720, 576)
video = BilinearResize( video, 1280, 720)

# --> SSIM analysis <--
return SSIM(source,video,"results.csv","SSIM.txt",lumimask=true)

Playing simulation of q2 MPEG4 ASP 720p encoding from 576p DVD on 720p screen : SSIM = 86.60

# --> Video Opening <--

source = DirectShowSource("Amazon_720.wmv")

video = DirectShowSource("XviD-720p-q2.avi")

# --> SSIM analysis <--
return SSIM( source, video, "results.csv", "SSIM.txt", lumimask=true)

Playing simulation of lossless 720p encoding from 576p DVD on 720p screen : SSIM = 94.02

# --> Video Opening <--

source = DirectShowSource("Amazon_720.wmv")

video = DirectShowSource("Amazon_720.wmv")
video = Lanczos4Resize( video, 720, 576)
video = Lanczos4Resize( video, 1280, 720)

# --> SSIM analysis <--
return SSIM(source,video,"results.csv","SSIM.txt",lumimask=true)


q2 576p encoding vs q3 720p encoding

Playing simulation of q2 MPEG4 ASP 576p encoding from 576p DVD on 720p screen : SSIM = 79.70

# --> Video Opening <--

source = DirectShowSource("Amazon_720.wmv")

video = DirectShowSource("XviD-576p-q2.avi")
video = BilinearResize( video, 1280, 720)

# --> SSIM analysis <--
return SSIM(source,video,"results.csv","SSIM.txt",lumimask=true)

Playing simulation of q3 MPEG4 ASP 720p encoding from 576p DVD on 720p screen : SSIM = 83.17

# --> Video Opening <--

source = DirectShowSource("Amazon_720.wmv")

video = DirectShowSource("XviD-720p-q3.avi")

# --> SSIM analysis <--
return SSIM(source,video,"results.csv","SSIM.txt",lumimask=true)

[SeeMoreDigital]

Hi bleo,

I don't think I'm missing the point...

My issues PAR has never been with regard to the ITU specification either... it's just that "others" keep bringing it up.

It sounds like you and I want the same thing. Maybe others do to!

I generate my DVD back-ups at 1:1, whether they be PAL or NTSC, 16:9 anamorphic widescreen or 4:3 standard.

After generating the encodes I often use Moitah's MPEG4 Modifier to apply/alter the AR signalling within the Mpeg4 video stream. And it was during this procedure I noticed the following anomaly...

When I applied "16:9 PAL" PAR signalling, my software media players reported this: -

http://img121.exs.cx/img121/8412/169PAL_PAR_setting.png


But when I applied "16:9" DAR (ie: 64:45 PAR) signalling, my software media players reported this: -

http://img124.exs.cx/img124/5779/169_DAR_setting2.png


When the encodes were visually checked against the source (using a verity of analogue and digital computer monitors and TV's). The pixel positions of encode with "DAR signalling" exactly matched the source... unlike the encode with "16:9 PAL PAR signalling".

This is the principal reason why I select DAR or use my own "custom" PAR settings.

It has never been my intension to cause arguments between forum members, only report my observations and invite other to confirm the same.


Cheers

[Sagittaire]

1024*576 1049*576 1048*576 or 1047*576 ... that doesn't change anything for my eyes and I prefer 1024*576 for mod16 and screen compatibility ... lol

but for ITU-R 601

328 / 225 PAL 16/9
82 / 75 PAL 4/3
40 / 33 NTSC 16/9
10 / 11 NTSC 4/3

[bleo]

My generalised observations are:

- If you want your encodes to have the same aspect ratio as the source viewed with a software DVD player, then encode at 1024x576 or with the generic PAR of 64/45.

- If you want your encodes to have round circles and square pixels then, in most cases, encode at 1048x576 or with the DV PAR of 16/11.

As always, the choice is yours! I am happy to help with any resizing calculations.

[SeeMoreDigital]

Originally posted by bleo
My generalised observations are:

- If you want your encodes to have the same aspect ratio as the source viewed with a software DVD player, then encode at 1024x576 or with the generic PAR of 64/45.

- If you want your encodes to have round circles and square pixels then, in most cases, encode at 1048x576 or with the DV PAR of 16/11.

As always, the choice is yours! I am happy to help with any resizing calculations. I totally agree with you...

I've also conducted tests for viewing via hardware/stand-alone players and ...

- If you want your encodes to have the same aspect ratio as the source viewed with a "stand-alone" Mpeg2/4 DVD player, then encode at 720x576 with the generic PAR of 64/45 (or 16:9 DAR).

Hardware players used: -
Sigma Xcard - with PAR/DAR signalling detection in MP4,
MK chip-set players - with PAR/DAR signalling detection in AVI
I-O DATA AVLP2/DVDLA and DVDG - with PAR/DAR signalling detection in MP4.


Cheers

[bleo]

@Sagittaire
What are you trying to show with your tests?

I might be interested in upsizing for HD displays...

[edit:]
Conclusions I have drawn from your tests so far: (some of them are obvious)
- Lanczos4 upsizing gives higher SSIM than bilinear upsizing
- Encoding to xvid q2 reduces SSIM
- Lanczos4 upsizing before encoding gives a higher SSIM than encoding at standard resolution at the same bitrate and bilinear upsizing on playback

[SeeMoreDigital]

Originally posted by bleo
@Sagittaire
What are you trying to show with your tests?

I might be interested in upsizing for HD displays... Don't waste your time creating upsized encodes from DVD sources... Your screen should be able do this for you, automatically.... mine does!


Cheers

[bleo]

Of course it upsizes automatically on playback, but like what was discussed earlier in the thread, I am interested in more control over the upsizing method. Even DVDs upsized to HD using whatever the default method of PowerDVD is, look rather disappointing :p

Also, I don't necessarily intend to upsize before encoding either. Perhaps a simple avisynth script for playback is all that is required...

[Didée]

Originally posted by SeeMoreDigital
Your screen should be able do this for you, automatically.... mine does! Well ... I could let some mates do the backup'ing of my DVDs. But how comes I prefer to do that by myself ...

Don't waste your time creating upsized encodes Okay, the following is a DVB source, not DVD. And okay, it shows (yet) some artefacts, since it's *WIP* of a certain processing chain, not finished yet. But nonetheless: imagine you have a source looking

like this:
http://img67.exs.cx/img67/3297/source_orig.jpg

Then a realtime upsize, be it SW or HW, will look

similar to this:
http://img67.exs.cx/img67/9378/source_upsized.jpg
- not more, not less.


But when blowing your recommendation in the wind, the travelling goes in

this direction:
http://img67.exs.cx/img67/5732/source_processed.jpg

(Save the last two to HD and switch forth-back)


Investing a little imagination on having the leftover artefacting solved (it's mainly a "only-8-bit" precision problem), you should get my point.

Once more: upsizing is not about "more detail", but about "better representation" of what is there.

Ever heard anyone saying "Bodybuilding is useless, because the mere number of muscles will not increase." ? No you haven't, because that's a nonsense argument, isn't it.
- But then, building up muscles is a slow process ...

[Teegedeck]

I can think of only one argument against upsizing to a square pixel aspect before encoding; but it is a rather decisive one: The question one would have to ask oneself before each encoding-session would be: Is the increased bitrate/space that is needed to encode the increased amount of pixels a meaningful investment or not? Whenever upsizing before encoding means encoding at a higher quantizer (because of your personal reasons for assigning this much, and not more, diskspace to a specific encode) the advantage of the more exact resizing might get lost, or so I think, and then the answer to that question would have to be 'no'.

Or do I go wrong here?

Edit: So it would seem to me that upsizing before encoding would be apt if you want to, say, increase the quality of your DVDs by upsizing with avisynth instead of letting the display driver do this, and for that aim are willing to sacrifice the ability to store more than one movie onto 1 DVD? Valid point, though not my cup of tea.

[708145]

Hmm. To me the last picture looks more artificial than the second.
On a CRT the effect was neglible but on a LCD it's very pronounced.

Are you sure you only changed the resizing method? Or is there sharpening involved?

bis besser,
Tobias

[Soulhunter]

Originally posted by 708145

Are you sure you only changed the resizing method? Or is there sharpening involved?

I think he used iip... ;)


Bye

[SeeMoreDigital]

Hi Didée,

While your enlarged and "processed" frame does at first site look impressive... you can't add more detail to an image if it isn't there to begin with - Only the illusion of more detail.

I have a 42" high-def screen (with component video, DVI and VGA inputs) and have done many tests but have found there's only so far you can go when it comes to increasing the vertical resolution. But like I say, whether it's worth the hassle is debatable.

All I need do to get the same effect as your "processed (960x544) image" is, increase the sharpness setting of my screen. Which is something I do (from time to time) when watching DVD's.


But I'm curious though...

The source you provided is from Enterprise, which is transmitted in some parts of Euroland at 1.777:1 using 720x576 pixels with an 1.777:1 anamorphic AR.... So how come your source image is only 704x432? Which after processing, has created a frame of 960x544. And therefor contains less vertical resolution than the DVB source!


Cheers

[PiXuS]

Originally posted by SeeMoreDigital
While the enlarged frame "does" at first site look impressive... you can't add more detail to an image if it isn't there to begin with - Only the illusion of more detail.



Hmmmmm... didn't Didée specifically said Once more: upsizing is not about "more detail", but about "better representation" of what is there. ???

Though... I believe Soulhunter is right... Didée didn't "simply" upsize using a more precise upsizer, but he processed the picture with iiP or LimitedSharpen or whatever Didée is brewing these days. :)

Personnaly, I cannot afford the amount of bits such a big picture demands. I prefer to encode in anamorphic and tell ffdshow to resize using Lanczos... when CPU's will be fast enough, I will use something other than Sharpen to do real time sharpening through ffdshow.

just my 2 cents...

[SeeMoreDigital]

Okay, I've ammended the first line of my previous post to suit. As I'm fully aware that Didée did not simply "enlarge" the image :eek:

Which is why I mentioned what I would do to obtain the same effect, when viewing via my HD screen!


Cheers

[Didée]

Oh-oh, what have I done :D

Firstly: No, of course that's not only a "simple" upsize. And it wasn't iiP, either. Instead I was toying around with the new features of LimitedSharpen's next version, and especially with the possibilities of doing uber-enhancement by chaining several insances of it. In fact, the last picture was done by 3 (three) serial instances of LS(), the first two with insane strength settings, and in-between denoising. You might try to put any other sharpener in a three-fold way ...


PiXuS: Dunno how it comes, but usually I'm encoding my upsized & sharpened clips with moderate bitrates (1000 to <3000, depending), at rather low quantizers ...


SMD:

"German" DVB isn't very impressive. And when something happens to get transmitted anamorphic, then we make a BIG red cross in the calendar :/
And the 960*544 is "1024*576, overscan-reduced" ... but that doesn't really matter here. It could be any resolution, and it was only testing-around.

Then, with all respect, I think you severely underestimate how poor those ENT sources look when they're in motion. That is, even on a "normal" 100Hz TV-set. I suppose you'd be very surprised about how really bad they'd look on your hi-def screen! (Especially since they're crappy field-blended, oh my.)

And, again with all respect ;) , I *absolutely* doubt that you can get THAT amount of sharpening by just increasing the sharpness of your screen. I know what insane settings I had to use, how badly the pre-present EE became over-prominent, and how much noise there had to be reduced to be able to enhance anything at all - but without loosing those details I wanted to get back ...

Also, consider the case that that source shall be re-encoded (although the source isn't good quality, it sucks too much bitrate: ~4500 kbps - big waste of space to store a poor looking source).
And if you "simply" re-encode such things, then you'll loose pretty much of those fine details that you almost can not *see* at all in that original source. Look at Jolene Blalock's lips. Look at the hair. Look at those small dots (how's the english word?) in her face, and at the fine texture at her neck's skin (latter is invisible in the source). You know very well how much of all of that you'll loose through fast&easy re-encoding: the biggest part of it, unless you go for (again) insanely high bitrates, to preserve those small, almost invisible details ... MPEG isn't suited that well for preserving such weak information.


Hey, I didn't say "this is what it has to look like". I only wanted to show how much detail (even "invisible" one) can be squeezed out, as long as it is there. Because after re-encoding, it's mostly gone and lost for sure.


The lame go to sharereactor & Co. -- I instead prefer trying to be creative, perhaps yielding to something usable and useful, at the end of the day. Let the lame be lame ... they're lame ;)

[SeeMoreDigital]

Originally posted by Didée
Then, with all respect, I think you severely underestimate how poor those ENT sources look when they're in motion. That is, even on a "normal" 100Hz TV-set. I suppose you'd be very surprised about how really bad they'd look on your hi-def screen! (Especially since they're crappy field-blended, oh my.) Actually, no I'm not surprised, because DVB-S and T is much the same here in the UK.

As I write this, I'm watching channel "five" via DVB-T on a Hitachi 1024x1024 high-def 42" plasma... and it looks bloody dreadful. If I switch over to analogue, it looks much better.... what a pisser!

But thanks for explaining a bit more how you generated your encode.


Cheers

[Sagittaire]

if hardware resize is ~ bilinear
if software resize (pre-process) is Lanczos

for metric on 720p screen:
1) 576p DVD source is better than 720p MPEG4 q2 encoding
2) 720p Lossless encoding is better than DVD source
3) 720p MPEG4 q3 encoding is better than 576p MPEG4 q2 encoding

[lamer_de]

My point, which I already rised on page 1 still remains: What if you process your image with those sharpeners, but keep the original resolution and encode at that res and then upsize during playback? I heavily doubt you can spot a significant difference during playback then.

Oh, and the sharpening you used reminds me heavily of xsharpen artifacts, especially prominent around that silverish thing in the background. Yeah, you already stated it was for demonstrating purposes only, just wanted to point out that the unprocesed one looks much better to me ^_^

CU,
lamer_de

[EnergeticBence]

Just who would watch an upsized video on a TV?
Even the best of them can't reproduce the quality of a good 22" screen.
What I do ( To prevent resize quality loss ) is set 1440x960 res on the screen @96Hz ( pstrip ) so I get no resize qiality loss and the screen is in sync with the movie... :)

[Didée]

Originally posted by EnergeticBence
What I do ( To prevent resize quality loss ) is set 1440x960 res on the screen @96Hz ( pstrip ) so I get no resize qiality loss and the screen is in sync with the movie... :)
Youthful optimism. There is no "quality loss" by upsizing to non-integer multiplies of the original resolution.


source (6x zoomed) :
http://img50.exs.cx/img50/8083/4f-source_zoom6x.png

upsized 150% (3x zoomed) :
http://img50.exs.cx/img50/8365/1e-upsize150_zoom3x.png

upsized 200% (2x zoomed) :
http://img50.exs.cx/img50/7449/2f-upsize200_zoom2x.png

I'm curious what "quality loss" you see in the 2nd one?


Even the best of them can't reproduce the quality of a good 22" screen.In exchange, your good 22" screen most likely has severe problems with interlaced content ...

[SeeMoreDigital]

Originally posted by Didée
..."German" DVB isn't very impressive. And when something happens to get transmitted anamorphic, then we make a BIG red cross in the calendar :/
And the 960*544 is "1024*576, overscan-reduced" ... but that doesn't really matter here. It could be any resolution, and it was only testing-around.) Actually, after re-reading your post, I would like to understand why you had to reduce an 16:9 anamorphic image containing 576 vertical pixels, down to 432 vertical pixels, prior to re-encoding!

Here's a typical UK DVB-T/S, 16:9 anamorphic 720x576 image from BBC News, without DAR correction: -

http://img122.exs.cx/img122/4623/0f-SMD_DVB-T_capture.th.png (http://img122.exs.cx/my.php?loc=img122&image=0f-SMD_DVB-T_capture.png)

And the same image again, with DAR correction: -

http://img122.exs.cx/img122/7453/37-SMD_DVB-T_capture.th.png (http://img122.exs.cx/my.php?loc=img122&image=37-SMD_DVB-T_capture.png)

As you can see, there's very little matte to crop away!

Are you saying, your DVB-T/S 16:9 "anamorphic" broadcasts are not presented like this.... I find this strange because I'm watching on right now!

[Didée]

In case I wasn't clear enough:

99.9% of all digital broadcasts in Germany are NOT anamorphic. So I did not reduce anything: we just don't get any more than that.

[SeeMoreDigital]

Thanks for clearing that up Didée.

I have to say, when watching "analogue" German TV via I've always been impressed to see content shown at it's correct "theatrical" aspect ratio.

With this in mind, I find it quite bizarre that more German "digital" TV stations don't transmit, what is obviously anamorphic content, correctly.

Earlier today, I watched a couple of "local" stations transmitting anamorphic content.... shame it wasn't something worth watching.


Cheers

[SirCanealot]

Originally posted by lamer_de
My point, which I already rised on page 1 still remains: What if you process your image with those sharpeners, but keep the original resolution and encode at that res and then upsize during playback? I heavily doubt you can spot a significant difference during playback then.



Because when you upscale in post-processing you upscale everything.
You upscalle everything. Everything. Details... and artifacts... :)

For example (based in NO facts, only logic :P):

Encode to 640x480 ; macro block = 1 pixel big
Upscale same encode to 1024x768 ; macro block = 4 pixels big (again, probably wrong, but you get the point)
Upscale source to 1024x768 before encoding ; end result - macro block = 1 pixel big

Upscalling after encoding = making blocking/etc bigger.
Heh, take a source, and encode it to say... Quant6.
Encode that source to 320x240 and 640x480. When you zoom the 320x240 version to fullscreen, all the blocking has been made 2x as large than when it was 640x480!

If you're upscalling before XVid (or whatever) touches it, of course it's going to look better.
I use post-processed upscalling via FFDShow a lot when I view anime. There's LOTS of limiations. Upscalling a shitty fansub source to 1280x960 only makes it look SHIT. The source needs to be perfect to look good when using post-processed upscalling.
Of course, assuming we're all "perfect god encoders", :), then upscalling after encoding can help add quality to an encode. However, it's still not as good as upscalling before encoding. End of story.

[HairDude]

To quickly come back to the original post...

"Should I encode at 720x544 (which is the same as the DVD)"

Wouldn't you be upsizing anyway if you use cropping (be it auto or manual) with let's say Fairuse Wizard? That normally always manages to find a few lines to crop off, even if it is a 16:9 Anamorphic image.

http://homepage.ntlworld.com/jontybigwang/fairusewizardfriday.png

http://homepage.ntlworld.com/jontybigwang/fairusewizardfridaycloseup.png

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HairDude