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xanas3712 Guru
Joined: 15 Oct 2004 Posts: 455
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Posted: Mon Aug 13, 2007 11:11 pm Post subject: x264/mkv sync is horrible! |
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I work this out sometimes but it never works for every video I do and it's just annoying.
I'm encoding a dvd I have and for some insane reason somehow the stupid x264 codec is actually making the video longer than the original.. but even stretching the audio isn't fixing sync in mmg so I have just no freaking idea what's wrong with it.
Is this wrong?
mencoder $2 -vf pullup,softskip,harddup$8 -nosound -ovc x264 -x264encopts qp=$6:subq=6:bframes=3:8x8dct:frameref=3:b_pyramid:weight_b:threads=3 -of rawvideo -o $3;
I figure something in the encoding is jacking the hell out of this thing. mp4creator I'm just using the 29.97 rate. My videos' are telecined I'm sure (hence pullup) because they alternate fps a bit during playback on occasion, but according to the documentation I keep reading over and over @ mplayer it seems that pullup should take care of this, at least none of the documentation says that I should need to do anything else.
Is this just a dumb mencoder issue? I don't see anything on forums, etc. about this elsewhere. I see people complain about av sync issues like I am but then others say it works fine for them. Problem is many of them are using windows/megui so difficult to compare.
Very frustrating stuff since it takes hours to encode only to find out it doesn't work, then I get it to work by changing settings and dumping bframe options... but I don't know why that should be necessary... because nothing says it should cause sync issues that I can find.
Trying avidemux now to see if it does any better, of course I'm having to use ogm since it doesn't mux to mkv hopefully it will be more reliable, even though it seems to take longer if it works the first time every time that will help!
EDIT:
well that doesn't appear to work, it desyncs when I'm using decomb telecide (I think this is what I"m looking for anyhow that's the same as pullup filter)
In any case no go with it either, with or without filter audio desyncs horribly but this may be ogm problem? |
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xanas3712 Guru
Joined: 15 Oct 2004 Posts: 455
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Posted: Tue Aug 14, 2007 9:47 pm Post subject: |
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I'm going to bump since it seems like not many know this stuff (since I received no reply here) and yet I think people still may need to find this thread.
Apparently sync can be destroyed by using the -nosound option. It makes no sense, but using -oac copy actually will help keep sync on weird video.
Anyhow good luck to anyone finding this on a search, it may not be the only thing you need to do, but it's the only thing I needed to do to get my otherwise working script to do the job for me. |
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MostAwesomeDude Guru
Joined: 12 Aug 2007 Posts: 373
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Posted: Fri Aug 17, 2007 10:51 am Post subject: |
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Specify your output FPS with -ofps. Also don't use -vf pullup or -vf softskip if there's no telecine. Finally, in -x264encopts, go ahead and use threads=auto; specifying too many threads can degrade quality and x264 will be fairly intelligent about allocating a healthy number of threads. |
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psofa Guru
Joined: 28 Feb 2004 Posts: 485
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Posted: Fri Aug 17, 2007 12:13 pm Post subject: |
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pullup iirc is supposed to give you 24 fps not 30 fps assuming the input is telecined.Apart from -ofps you have also to define the input rate with -fps _________________ psofa |
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xanas3712 Guru
Joined: 15 Oct 2004 Posts: 455
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Posted: Fri Aug 17, 2007 7:47 pm Post subject: |
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I believe it is telecined, according to the documentation you can tell this by the alternation of framerate between "detected NTSC 29.97" & detected NTSC 23.976 or something to that effect.
In any case my problem was solved not by stopping use of pullup or softskip, but by using the -oac copy option, instead of -nosound. -nosound can destroy sync apparently, I've confirmed this as all of my encodes since I switched from -nosound to -oac copy work fine.
I am also using 24000/1001 on -ofps though, so I'm sure you may be right that's what I should be using. I decided it probably made more sense, though I had previously used 30000/1001 and had it turn out fine (with some tuning of the stretch options in the mmg gui)
It's all good now though, thanks for replies on this. |
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