Stand-alone player compatibility

[kitanai]

Hi,

I continued an AVISYNTH thread about adding borders to a movie.
http://forum.doom9.org/showthread.php?threadid=68170

It might better be asked here: does anyone have experiences with XviD and stand-alone players?

The question is, wether to add borders to get to a resolution of 720x??? or 704x??? to get maximum compatibility...

[Manao]

Compatibility isn't an issue here, MPEG-4 is far less restrictive than MPEG-2 on resolution. So you can aim to whatever resolution you want ( I would recommend however a mod 16 resolution, for efficiency and because I do not know exactly what are the stand alone requirement on that matter )

However, if you still want to add black borders ( for any other reason than compatibility ), take a great care to make their width dividable by 16, and that your video( before adding borders ) is also mod 16. ( in order not to have macroblocks over both the border and the picture, which would decrease the quality of the video, and oncrease the bitrate ).

Moreover, you seem to want to fill the whole DCD with your movie. Do not forget that most ( if not all ) stand alone can't decode MPEG-4 in real time if the bitrate is too high. So you'll have to take care of that detail.

[Zhnujm]

Usually the resolution is not important (if its mod 16 and has a correct aspect ratio).
But some ESS based players cannot display resolutions around 624xXXX - 688xXXX at fullscreen (at least not in PAL), you will have borders on your TV.
So for maximum compatibility you should avoid this resolutions.
Or just buy a better player...

[kitanai]

Thanks for the detailed answers! :)

What will the player do if it gets a file with a resolution below 720x576? Scale up or a black border???
This question is important, since I would like to avoid scaling on TV by adding these black borders...

I aim at a bitrate of about 3300. Will that be too high to playback smoothly?

Ok, am I getting this right: my original resolution is 688*560. To get the PAL resolution 720x576, I add a border of 16 to the right and 16 to the left. Should be no problem.
But 8 at the top and 8 at the bottom might cause macroblock issues? :eek:

[Manao]

The maximum bitrate should be specified on the standalone documentation. With a little search ( here or on the net ), you should also be able to find suxh limitation for some well known stand alone.

However, if your average bitrate is 3300, on fast motion scenes, the bitrate could go up to 6000 or even more, if it doesn't have a working bitrate regulator, so you'll have to check that, if you don't want some sluttering on fast scenes.

For the 8 pixels borders, it should be OK, but not optimal ( you'll raise slightly your bitrate ) but at least ringing artifacts won't come up. ( Edit : I forgot to take into account the chroma. You'll lose some coding efficiency and get ringing on the chroma, but it's less visible, so it's up to you ( hint : go to 16... ) )

For the rest, I don't know.

[Zhnujm]

Usually players scale lower resolutions up to fullscreen.

But im not sure if you really want a resolution of 720x576, this would not be "correct" for avi files as they use a pixel aspect ratio of 1:1.
In your case, the target resolution should be 688x528 or 720x544. Otherwise you wont have a correct playback with Sigma and Mediatek based players.

If you really want to crop only without resizing AND have correct playback you have to use an ESS based player (wich play such files correct, but others not) or a Mediatek based wich supports ar settings in avi files (set to 4:3 pal for correct playback).

Assuming that you play your files from dvd, 3300kBit should be no problem for Sigma and Mediatek chip, but may cause problems with ESS based players if there are very high bitrate spikes.

Also, for maximum compatibility dont use Xvid with GMC,QPEL, Custom Matrices or more than 1 bframe.

[SeeMoreDigital]

Hi Zhnujm,

It sounds like kitanai might be interested in one of those MediaTek players you've found that can playback anamorphic Mpeg4 streams!

It was an MT player wasn't it?


Cheers

[kitanai]

To be honest: this is all quite confusing :scared:
Usually players scale lower resolutions up to fullscreen.I definitly do not want scaling, so I guess borders come into play.
In your case, the target resolution should be 688x528 or 720x544.Why is that? Just to maintain 720/544=1.3 instead of the recorded 720/576=1.25 :confused: and to make the stand-alone player happy...

[edit] OK PAL has a res of 768x576, that explains a lot.
Wouldn't have to go even at 768x576 with my borders to avoid scaling (we are getting an absurdly high resolution here, I think)...

It is hard to judge from the monitor screen to the TV if the aspect ratio is somewhat distorted...

The thing is: I also want to play the files on my computer until I can finally decide for a player ;)
Therefore, the files should be ok to view on both! But from what you are saying, it seems I have to decide for ONE solution.

My conclusion: keep bitrate a little lower for better playback compatibilitiy
tell GordianKnot "Input Pixel Aspect Ratio" to be "PAL 4:3 anamorphic", which shrinks the size from 720x576 to 720x528
a littel cropping here an there and adding borders to come up with 720x544
no GMC, QPEL, more than 1 bframe (was that the setting "Max consecutive BVOBs" :o)

Please correct me if I am wrong here...

[Sharro@Home]

Originally posted by kitanai
...

My conclusion: keep bitrate a little lower for better playback compatibilitiy
tell GordianKnot "Input Pixel Aspect Ratio" to be "PAL 4:3 anamorphic", which shrinks the size from 720x576 to 720x528
a littel cropping here an there and adding borders to come up with 720x544
no GMC, QPEL, more than 1 bframe (was that the setting "Max consecutive BVOBs" :o)

Please correct me if I am wrong here...

Depends very much on standalone:

-New MT1389EE can cope with bitrates 5.500kbps (average of my experience was 2.380kbps with a max of 5.459kbps)
-I upsize to 720 after cropping, no borders, and no problems.
-I agree on not using GMC (MT1389 either DE or EE don't play it smoothly), I use QPEL a 2B-frames and they play flawlessly. Also important is Packed Bitstream (should be off for MT1389DE but EE plays it without problems).

Just my 5 cents.

All the best,

Sharro

[Zhnujm]

Originally posted by kitanai
The thing is: I also want to play the files on my computer until I can finally decide for a player ;)
Therefore, the files should be ok to view on both! But from what you are saying, it seems I have to decide for ONE solution.


The resolution gknot gives you should be correct for pc and standalone playback. I only came to a different resolution (720x544 instead of 720x528) because i always disable the "Follow ITU ..." option in gknot.
But that are only 16 pixels.

[kitanai]

Disabling the "Follow ITU ..." option in gknot seems to be a good choice in this case. The aspect ratio improves from 1.364 to 1.324 (yeah, ok it's almost unnoticable, but... :p )

After cropping I get 688x528 which is 1.303 :)

Since aspect ratio is fine, now, and playback seems not to be an issue on PC nor on TV: how about the final resolution?

Is creating a full PAL resolution of 768x576 by adding borders recommended or simple overkill? (After all, that is an increase of appr. 80.000px/frame)
After all: I have no idea, what a 10% up-scaled MPEG4 would look like on a TV screen.

[SeeMoreDigital]

Originally posted by kitanai
Is creating a full PAL resolution of 768x576 by adding borders recommended or simple overkill? Unfortunately this is not an option as an 768x576 pixel frame size would contain a total of 442,368 pixels and all the current chip-sets only support a maximum of 414,720 pixels.

EDIT: This is where NTSC users have more luck than us PAL users when it comes to 4:3

Cheers

[Zhnujm]

And most players cannot even play files above 720 pixel, even if the vertical resolution is below 576.

Originally posted by kitanai
After all: I have no idea, what a 10% up-scaled MPEG4 would look like on a TV screen.

Maybe this is helpful to get an idea:
I have taken 3 screenshots, one from a 720x576 encoding (with 4:3pal setting for right playback), one from a 720x544 encoding and one from a 688x512 encoding.
Of course all are played a bit different, but wich one is the best or worst ?

ftp://zhnujm.dyndns.org/Bild1.png
ftp://zhnujm.dyndns.org/Bild2.png
ftp://zhnujm.dyndns.org/Bild3.png

[kitanai]

Thanks for posting those samples :)

As far as I can tell, pic 1 and 3 are almost similiar in aspect ration. Pic 2 seems a little squeezed horizontally (there seems to be more border on the right and the left, I think).

I will go for 688x528 then. Maybe one fine day, stand-alone player will play what we feed them...

Originally posted by SeeMoreDigital
This is where NTSC users have more luck than us PAL users when it comes to 4:3*dream* Wouldn't it be great to have just one all-compatible video system :cool:

[kitanai]

Just one last question:

I just found out that with a little tweaking, I can even capture at 768x576.
Since that is already 4:3, the "Input Pixel Aspect Ration" in Gknot should be set to 1:1 !?!

[Zhnujm]

That should work.
But then you also have to change the Input Resolution to 768x576

[kitanai]

Thanks. I should be all set,now :)