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Old 11th June 2005, 19:08   #221  |  Link
dimitrik
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Workaround for OpenDML limitation if file<2GB

One way to get around mpeg4modifier's limitation on OpenDML avi's is to convert them to regular avi's if the file is less than 2GB is size. AVI's over 2GB can only be in OpenDML avi format.

However for smaller files, you can load them into VirtualDub, set both video and audio to 'direct stream copy' and then save the files with the 'save as avi' option. The result is a regular avi that you can open in mpeg4modifier and unpack (though all my OpenDML files turned out not to have packed bitstream anyway).

Is there a way to see if they have PB, before loading them in modifier?
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Old 12th June 2005, 12:58   #222  |  Link
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problem

I've just unpacked a whoe bunch of my videos but I noticed somethign worrying.

Many of my DivX cartoon encodes, when unpacked play back with a stuttering in high motion scenes. Moving objects appear to shake. This was the case in at leat a dozen animated encodes I checked. I compared them to the originals and the shaking is not there. Xvid files don't seem affected.

The strrange thing is that problem is visible when using Windows Media Player 9 and PowerDVD but it doesn't happen with Media Player Classic, VLC or DivX Player. I haven't tried them on my standalone yet.

I dont know why it happens in some cases, maybe it has something to do with how b-frames are decoded?

Any advice would be appreciated.

Last edited by dimitrik; 12th June 2005 at 14:30.
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Old 12th June 2005, 15:48   #223  |  Link
Vladdy
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Quote:
Originally Posted by dimitrik
One way to get around mpeg4modifier's limitation on OpenDML avi's is to convert them to regular avi's if the file is less than 2GB is size. AVI's over 2GB can only be in OpenDML avi format.

However for smaller files, you can load them into VirtualDub, set both video and audio to 'direct stream copy' and then save the files with the 'save as avi' option. The result is a regular avi that you can open in mpeg4modifier and unpack (though all my OpenDML files turned out not to have packed bitstream anyway).

Is there a way to see if they have PB, before loading them in modifier?

I have a number of avi files that are roughly 2.5->3gb in size. And I don't want to split them either. Is there any other app that can modify the aspect ratio in avis? And that supports opendml?
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Old 24th June 2005, 22:14   #224  |  Link
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Are there plans to introducing MPEG4/H.264 support?

The "x264" codec for Windows is showing a good level of maturity at this point, as is the new "FFDShow". It would be nice to be able to modify AVIs with these video streams as well.

Keep up the good work and thank you VERY much for your tool!
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Old 27th June 2005, 11:27   #225  |  Link
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I don't know how to modify my file with this tool to obtain my target:my avi is 704*346 taken from a pal dvd.I watch it with an Amstrad standalone player.The images are too long horizzontaly. I could changhe the resolution to something like 704*304 but i must re-encode to do that. It's podssible do something with this tool? I put the AR ratio to 2.35:1 but on my standalone nothing as changed,why?Which setting should i try?
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Old 27th June 2005, 12:12   #226  |  Link
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Yes.... 704x346 gives an square pixelled aspect ratio of 2.034:1. That said, 346 vertical pixels is very unusual because is does not conform to mod16, mod8 or mod4.

If the resolution (pixel frame size) of your encode really is 704x346, I'm very surprised your Amstrad can play it at all.

Plus, are you 100% sure your Amstrad can detect PAR/DAR signalling?


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Old 28th June 2005, 07:53   #227  |  Link
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Originally Posted by SeeMoreDigital
Yes.... 704x346 gives an square pixelled aspect ratio of 2.034:1. That said, 346 vertical pixels is very unusual because is does not conform to mod16, mod8 or mod4.

If the resolution (pixel frame size) of your encode really is 704x346, I'm very surprised your Amstrad can play it at all.

Plus, are you 100% sure your Amstrad can detect PAR/DAR signalling?


Cheers
That is the resolution for sure, i found it with Gspot; i don't know really if my amstrad can detect PAR/DAR signalling this evening i'll check the manual but i think ther's nothing about on it.What should i change with mpeg4modifier?It seems that also with mpclassic 6.4 on my pc the movie plays always with the same Aspect Ratio even if i set it to 2.35:1 or 16:9...
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Old 28th June 2005, 08:40   #228  |  Link
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Hi boombastic,

It's vital you find out if your player supports PAR/DAR signalling detection.

Because if your player doesn't, there's no point in you using MPEG4 Modifier to add/change it

Here's a link to a .ZIP file containing 2No "video only" 16.9 AR Signalling Test Encodes. One has an Mpeg4 stream in .AVI, the other has an Mpeg4 stream in .MP4.

Burn the .AVI file to disc and try it in your player!


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Old 28th June 2005, 15:49   #229  |  Link
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I can watch the avi file, and then...?I'm a bit slow!Does it mean that my player supports PAR/DAR signalling detection?Just because i can watch that file?
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Old 28th June 2005, 16:10   #230  |  Link
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Quote:
Originally Posted by boombastic
I can watch the avi file, and then...?I'm a bit slow!Does it mean that my player supports PAR/DAR signalling detection?Just because i can watch that file?
Is the encode displayed at the correct aspect ratio on your TV screen?

If you have a 4:3 TV you should see black mattes (bars), above and below the image. If you have a 16:9 TV the image should completely fill your screen. Provided that is, your stand-alone player and TV are correctly set-up!


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Old 28th June 2005, 16:23   #231  |  Link
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Doh!I've got a 4:3 TV, if i set 4:3 format in its setting i can't see no black bars, if i set 16:9 the black bars appear.I think that this meens that my player doesn't support PAR/DAR signalling detection.
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Old 28th June 2005, 17:20   #232  |  Link
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Quote:
Originally Posted by boombastic
I think that this meens that my player doesn't support PAR/DAR signalling detection.
Agreed

What's the model number of your Amstrad?


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Old 28th June 2005, 19:39   #233  |  Link
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It's a dvd recorder that can also play avi files.It's DR300
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Old 30th June 2005, 00:37   #234  |  Link
Leolo
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Quote:
Originally Posted by SeeMoreDigital
Moitah,

I've just made a suggestion to sysKin. How about renaming the "Display AR" section to... "Pseudo DAR"?



Just a thought


Cheers
I second this motion. I've been thoroughly confused by the "DAR" option in MPEG4Modifier for a long time! Thank God I found this thread to find out what does it really mean.

SeeMoreDigital, I'd like to ask you a question: what is the difference between FAR (Frame Aspect Ratio) and DAR (Display Aspect Ratio)? When should I use them?

If I understood it correctly, PAR describes the shape of the pixels, FAR describes the shape of the whole image and DAR describes the shape of the physical TV set that is sitting in your living room. Is that correct? Please correct me if I'm wrong!

Thank you very very much.
Best regards.

Last edited by Leolo; 30th June 2005 at 00:44.
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Old 30th June 2005, 09:36   #235  |  Link
yaz
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@leolo
i'm quite simple-minded, so i tried to simplify this problem to my level look :

dar = par x sar (the basic equation)
what u always got is sar (the dimensions of the frames in the stream pixelwise). instead of bothering with the meaning of 'display aspect ratio', consider dar as a request (say, 'i want to display that stream in that dimensions'; 4:3, 16:9, whatever) so the task is to find a par fitting the requirement -> par = dar / sar easy then ...

e.g.
- u have sar=720x576 (pal dvd) = 5/4
- u want it to play back at dar=16/9
- u must set par=(16/9)/(5/4)=64/45
this 'par' is usually called as 'custom (p/d)ar' or 'custom pixel shape'

what may confuse u (it confused me, at least) is the standard values for par listed many time here and there. it is 16/11 for a '16/9 pal dvd' which is 64/44. this slight discrepancy is coming from the different sar presumed (it'd be 704x576 for pal dvd) let's see:

dar = (16/11) x (704/576) = (16/11) x (11/9) = 16/9

so, setting par to 16/11 results in a 16/9 playback of a '16/9 pal dvd' (what a surprise )

ok, getting back to mpeg4modifier.
u can set the 'standard' or the 'custom' par values in the left column or u can set the standard dar values in the right. either way u get the same result.

i hope it helps a bit

the bests
y

Last edited by yaz; 30th June 2005 at 09:41.
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Old 30th June 2005, 10:04   #236  |  Link
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There's not a lot more I can add.....

In essence, I personally prefer to use DAR signalling calculations because I generate my back-up encodes at full DVD resolutions (ie: 720x576 for PAL or 720x480 for NTSC).

And the DVD format uses DAR signalling calculations because there are after-all only two shapes of TV (either 4:3 or 16:9) in the known universe

Unfortunately for us all, it's taken rather along time for software player/direct-show filters manufacturers to include reliable AR signalling detection... And even longer for stand-alone player/device manufacturers to do the same... Which is confusing the hell out of people!


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Old 30th June 2005, 18:32   #237  |  Link
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Thank you Yaz and SeeMoreDigital!

It's much clearer to me now.

Also, I've found a post by Stegre here that explains it as well:
http://forum.doom9.org/showthread.php?s=&postid=562048

It seems that a lot of people are confused regarding Aspect Ratios, because I've seen quite a few AVI files with a resolution of 800x336 pixels and MPEG4Modifier shows that they have PAR signalling set to "16:9 NTSC"!

Thankfully, with MPEG4Modifier it's very easy to select "Square Pixels" and the problem is rapidly solved.

Regards.
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Old 30th June 2005, 23:00   #238  |  Link
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Yes, the entire subject of anamorphically shaped encodes can be a difficult one to grasp!

And it does not help when people try adding AR signalling to encodes that don't require it


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Old 26th August 2005, 17:43   #239  |  Link
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Loading: 0,0%Error: No VOL found before first VOP

what's up with that? (GUI version says the same)
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Old 26th August 2005, 23:10   #240  |  Link
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Quote:
Originally Posted by QQ
Loading: 0,0%Error: No VOL found before first VOP

what's up with that? (GUI version says the same)
Maybe someone cut the video so that it doesn't start with a keyframe. Does it look okay when you play it?
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