720 vs. 480, XSVCD vs. SVCD your opinion wanted

[markrb]

Now that DVD2SVCD has the DVD full size included I have been playing a little with resizing the video to the XSVCD size of 720 x 480. I am lucky that my DVD player plays these fine. In my way of thinking 720 has the benifit of not being resized while it has the drawback that it takes more bits since it is larger.
In your opinion what is better? Do you stick with the SVCD spec of 480 or do you prefer the XSVCD size of 720 and why?

Mark

[Clixo]

now i only go with 720 i looks mutch better and it play fine either in 6 per 4 and 16 per 9

[orbit-r]

hi
i keep on the svcd resolution cause i believe for thr dvd resolution 720x576 we don`t have enough space(and there for low bitrate) . maybe if we were doing 3 or 4 cd conversions(for a max. about 120 mins) 720x576 would be nice but me prefers 2 cds with sharp picture. ive done some tests with xsvcd(720x576) and the picture looks not so good as 480x576.

but im going to test some more with the sharpen command with 720x576

gruss
orbit-r

[mrbass]

if it takes 4 or 5 svcds at 720x480 and it looks just a tad better than 480x480 which are 2 to 3 svcds than I'd rather just skip that altogether and do dvd 1:1 copies on dvdr using ifoedit. Still want to know how much better it looks though in your opinions.

[Pko]

Originally posted by markrb
Do you stick with the SVCD spec of 480 or do you prefer the XSVCD size of 720 and why?


Depends on source...

If original stream is PAL full screen, 720x576@25Hz, I think that even at the lower PAL framerate, the standard resolution is too large and I usually resize to 352x576; for me gives better results than 480x576 (standard) and of course than 720x576

But if the original stream is NTSC FILM widescreen, 720x480@24Hz, and with two big black bars, then 480x480 is good enough and probably 720x480 will be even better.

So, with intermediate resolutions/framerates is more difficult to decide... I usually stick with standard SVCD bitrates, of course if you go to a bitrate high enough then you can use the higher resolution always.

BTW, 352x576 (or 352x480) has de advantage of being a DVD-standard resolution, so if you make in the future a DVD-R out from some SVCDs, you will only need to remultiplex to do 100% standard DVDs (well, audio must be 48KHz also, but I almost always use 48KHz for my SVCDs too, since it gives better quality if the source is at that same frequency)

[markrb]

One thing that actually confuses me a bit is the ratio we use for SVCD's. We use a 480 x 480 resolution when standard NTSC TV's are 4:3. Isn't 720 x 480 actually better matched since this is 4:3?
Does the resolution change affect the aspect ratio at all?
Is the video pulled, pushed, compressed or otherwise changed to fit?
VCD's are 352 x 240 again 4:3.
Does us changing the video to 1:1 change the visible part? Like does a person become taller or shorter like when we stretch 16:9 material into a 4:3 encode?

This is probably so newbie I should be ashamed, but I skipped a few days in encoding class.

Mark

[GreenDrazi]

heh, heh, heh.

Me thinks bits is bits. Right?
I mean that a 720x480 XSVCD encode with X number of bits has to be the same quality as a 480x480 SVCD (preserving the same display ratio) with X number of bits multiplied by (720x480/480x480 display ratio).
Assuming your DVD player can handle an XSVCD of course.
If your DVD player can handle it, the 720x480 XSVCD disc(s) should actually be pretty close to the same display quality if using the same number of discs.

However, if the XSVCD is a closer match to the original aspect ratio, then it should be the better solution because it more acurately displays the original image. But, don't the new ratio options in DVD2SVCD reslove this??

If you get into 4 or more discs for let’s say a 2 hour DVD, because you're using the same bitrate for encodes that you used on 480x480, you have to start to consider if just buying another DVD would be a better option.

Of course, my humble opinions here are all based upon my experience with Photoshop.
Time to go rip a chapter of the Matrix or Private Ryan to confirm all this. No wait, I've got too many 4:3 TV shows to convert first.
uuggghhh, IVTC and Smart-Deinterlace - what a pain. But they do work!!

[Linux]

I think it would be nice to have an option to use 352x480 or 352x576 instead. This only to save some more bits.

[markrb]

Just edit the avs script. Takes 2 seconds. You can make it any aspect you want that will work with CCE.

Mark

[DVDHack]

I've been encoding at 720x576 for some about 3 months and find it an excellent commpromise. I intend to upgrade to a 16:9 tv at some stage and I wanted to encode for that format but I also wanted to be able to use the encodes on 4:3. With a standard 480x576 encode I would end up with very elongated images that were difficult to put up with but I didn't want to encode heaps of dvds and have black bars all around on my new 16:9 when I get it.

720 x 576 doesn't give you the correct aspect ration on 4:3 but it is a lot better - you end up with black bars that are quite close (it would be correct if the image was 768x576).

Quality of 720x576 should be very good. Resizing does not need to be done hence there is no distortion in that respect. I try to keep bitrates up around 1900, I use 4 pass now (got a faster PC) but works great at 3 pass.

[DobbyPower]

Logically I guess it's got to be 720x576 being the better quality as this undergoes 2 less horizontal resizes (1 in compression , 1 during playback )

But, not all DVD players will cope with 720 as a horizontal resolution for SVCD ( for moving pictures ), so for compatibility I would say stick to 480x576

[Pko]

Originally posted by DVDHack
I've been encoding at 720x576 for some about 3 months and find it an excellent commpromise. I intend to upgrade to a 16:9 tv at some stage and I wanted to encode for that format but I also wanted to be able to use the encodes on 4:3. With a standard 480x576 encode I would end up with very elongated images that were difficult to put up with but I didn't want to encode heaps of dvds and have black bars all around on my new 16:9 when I get it.


I do not understand what the resolution has to do with aspect ratio of the TV, since TVs do not use square pixels...

I make SVCDs usually at 480x576 and 352x576, and I have a few at 720x576 and all of them look correctly in all TVs I tried, 4:3 or 16:9

Of course, if the SVCD is WS, if I use zoom on the 16:9 TV to see the picture at full screen (the black bars at top and bottom go off the screen), the lower resolution shows, but the horizontal 480 is less important than the vertical resolution (it is 576, but more than half of it is out of the screen, so the effective vertical resolution is around 250!)

720x576 introduces too much artifacts for my taste, even at full 2600 video bitrate, for most movies (and also requires 3 or more CDs), unless the movie is VERY wide screen. Of course, this varies from movie to movie and also from viewer to viewer, so try and select what works for you. I do not recomend going too much out of specifications unless there are clear advantages, though.

[DVDHack]

Pko,

I encode without the black bars at all which become a problem with 16:9 DVDs. If I use these with a 4:3 TV, the image is very stretched vertically. Now I could encode with the black bars, as I expect you do by your comments but then I would need to stretch the SVCD image in two directions for a 16:9 TV, the first stretch is horizontal as none of the standards we use give a 16:9 aspect ratio (anamorphic is designed to be stretched horizontally on a 16:9 display device), the second stretch is the vertical to remove the bleck lines that you add when encoding (these are no longer necessary for a 16:9 display device).

I believe that the vertical stretch degrades the image substantial hence I have opted to remove the need, the compromise is the minor stretch I get on my current 4:3 TV.

There is a great post here which discussed aspect ratios and the degredation caused by various encodes and display devices, it provides some examples of the sort of problems - "An amazing thread about 16:9 versus 4:3 aspect ratio", it was a sticky but seems to have disappeared - I just did a couple of quick searchs but couldn't find it, have a try.

[DVDHack]

Pko,

I think the post is http://rilanparty.com/vbb/showthread.php?s=&threadid=5905 but it may have been lost since it didn't work when I tried it, which would be a huge loss. I found it under Q11 in the Q&A - who'd ever look for it there !! LOL

Moderators,

Perhaps the post could be recovered. It really was very good.

[Pko]

Originally posted by DVDHack
I think the post is http://rilanparty.com/vbb/showthread.php?s=&threadid=5905 but it may have been lost since it didn't work when I tried it, which would be a huge loss. I found it under Q11 in the Q&A - who'd ever look for it there !! LOL

I do not remember the threas, a pity, it seems interesting.

I see what you do, but I think is not a good idea...

if your source is anamorphic, you can encode as it is (480x480 instead of 720x480), it will remain anamorphic; it will appear "thinned" in a 4:3 display with no "widescreen" option but so will the original.

If the original was NOT anamorphic, since the resolution was 480 in vertical, and it will remain 480 in the SVCD, when you chop off the black bars you are extrapolating 480 lines from, let's say, 300 (480 minus the bars), so you are getting poor quality (the information was not there), bad encode (too much information to SVCD's low bitrate) and "thinned" display in non-ws TVs

The 16:9 effect is usually implemente not by increasing in the "x" axis, but by compressing the "y" axis (in a TV there is no real dots in the "x" axis, only in the "y" axis since the electron beam makes horzontal "passes"). It is implemented by the electron beam making the horizontal lines more close together. The horizontal information is simply an analog signal generated by the information on the source (with 480 "modifiers" or with 720, depending on source, but an analog signal in any case and hence, less accurate).

That is why the vertical resolution is way more important for a good display than the horizontal, when you are making anything to be viewd on screen. That is why SVCD resolution is 480x480 (down from 720x480) and not 720x320, for example...

[Linux]

My recipe when it comes to high quality is use standard SVCD size, use high bitrate settings (many disc), convert with Bilinear to a 16:9 anamorphic movie.

There seem to be a belief that higher pixel number automatically lead to higher quality.
The main thing when it comes to picture quality on a movie is bitrate.
The second is bitrate and third is bitrate.
This is the reason to do VBR. Variable bitrate saves the unused bit to more needy places. One big difference between encoders is the use of available bits.
To make it easy for the encoder takes either that you let it use a lot of bitrate or you make the picture easier to compress so it needs less bitrate.
Since the SVCD standard for bitrate (2.6Mbit/s) is the same that most DVD-players is capable to play it leave little room to make the picture better by using more pixels. The other way is possible anyway. By lowering the size it is possible to make the compression higher.
One other thing is that 352x480 or 352x576 is also a DVD standard which standard SVCD size is not.
I think that the reason that some gets better picture when doing 720x480 is that the resize that precedes the compression make distortions.
Most high quality movies is made anamorphic widescreen 16:9. If most people resize this to 4:3 nonanamorphic (with black bars) this leads to downsize in both width and height. Many does this conversion with Bicubic that mainly should be used when upsizing.
If the conversion where done to 16:9 anamorphic, there would only be downsize in width. Since 480 is exactly 2/3 of 720 this is an exact resize which should be done as Bilinear or SimpleResize.

[DVDHack]

So what you are saying is that maybe bitrate affects quality.... I do agree and my main reason for sizing the image as I do is to enable quality playback in 4:3 now without the TV needing to do a second resize in both directions when I get my 16:9. Its a compromise.

In terms of resolution, I prefer to encode in 720x576 also for playback on future high definition TVs and projectors. I tried an SVCD on a projector with both 480x576 and 720x576, the difference is quite startling.

High bitrate provides for low artifacts and smooth motion but resolution provides for the detail.

[markrb]

In my case my DVD player will play bitrates as high as 5500. It is a 3 disc changer so I have been making all my encodes 3 discs with as high a bitrate as possible to fit. I only change the choice of cdr to use based on the length of the movie. Up to 108 minutes I use 80 minute discs, from 109 to 115 I use 90 minute discs and anything over that length uses the 99 minute discs. With these bitrates I can see a definate difference with 720 over 480.

I think there is a definate plus of both sizes. With lower bitrates the smaller screen is better since it uses more bits in a smaller area. WIth 720 you don't have nearly as much video processing for size.

Mark

[DVDHack]

@Markrb

What DVD player do you use, I'm looking for one that competently plays 720x576 at higher bit rates (3000) and preferably 3 or 5 disk changer.

[markrb]

It's a cheap ass Apex 5131. It plays a little dark so I adjust the brightness a little when I encode to compensate.
Making a 3 disc VBR with 5000 MAX and around 2900 AVG and not having to get up to change discs, Priceless.
Apex is comimg out with a new model. It's the 5151. It's a 5 disc changer. I believe it's based on the 5131 so the bitrates should remain the same.
I don't use it as my DVD player though, only SVCD's since I believe my Pioneer puts out a better image on DVD's.

They are Chinese I believe so you should be able to get them Down Under. The 5131 here costs around $129 American. I bought an extended warranty since it is built a little cheaply, but what do you expect for less then $130?

Mark