[MPlayer-users] Slow playback of x264 video in mkv

[Loren Merritt]

On Sat, 24 Sep 2005, Fredrik Eriksson wrote:

> Fredrik Eriksson wrote:
>
>> So, I created a x264 video with mplayer using the following command:
>> 
>> mencoder-cvs -dvd-device koikoi7.dvd2.real.iso dvd://1 -chapter 1-1 -ofps 
>> 24000/1001 -vf pullup=::::1:,softskip,hqdn3d=4:2:2 -nosound -ovc x264 -of 
>> rawvideo -x264encopts 
>> subq=6:frameref=7:me=3:4x4mv:bframes=4:b_adapt:b_pyramid:qcomp=0.7:keyint=300:8x8dct:pass=3:bitrate=1400 
>> -o koikoi7.intro.x264.h264
>> 
>> then I muxed the video to a mp4 container:
>> 
>> MP4Box -fps 23.976 -add koikoi7.intro.x264.h264 koikoi7.intro.x264.mp4
>> 
>> the video plays just fine with mplayer-cvs, with about 20% CPU usage.
>> But then I mux it to a mkv container:
>> 
>> mkvmerge -o koikoi7.intro.x264.mkv --timecodes 1:timecode.tmc --vtracks 1 
>> koikoi7.intro.x264.mp4 -a 0 koikoi7.intro.audio.ogg
>> 
>> now the video playback is too slow and jaggy, the audio gets quickly out of 
>> sync, although the CPU usage is about the same as with the mp4 file. I 
>> tried the file on my laptop, and the special build of ffmpeg included in 
>> CCCP (http://cccp.kickassanime.org/) could play the file just fine, so it's 
>> most likely not a problem with the file.
>> 
>> does anyone know what the problem might be?
>
> It appears that it's the b_pyramid option that is the culprit here, the same 
> file encoded exactly the same way, except for the b_pyramid option plays just 
> fine. Well, this solves the problem for me, but it might be something for the 
> devs to look in to.
>
> Fredrik Eriksson

There's a known bug in Mplayer involving b_pyramid + variable framerate, 
though I didn't hink it would occur if you're just using timecodes to 
enforce constant framerate...

--Loren Merritt