x264+AAC in FFmpeg -- plays fine in FFplay, loses sync in mplayer

[rusmichal]

Hello,

I'm encoding some videos from my camera (mjpeg+mp3) to x264+aac in FFmpeg. Here's the command line I use:

ffmpeg -i "in.mp4" \
  -vcodec libx264 -preset veryslow -crf 25 \
  -af "aresample=44100" -async 1000 \
  -strict experimental -acodec aac -ab 192k \
  "out.mkv"

What happens is... when I play out.mkv in ffplay, it plays fine. When I play it in mplayer, audio is played a bit ahead of the video. It is possible to play out.mkv in mplayer in sync, when I add "-autosync 1000" option to mplayer command... Other videos (those not encoded by me) play fine without this option.

It's the same without "-async 1000" in FFmpeg command... I'm using newest FFmpeg (2013/04/01). This behavior replicable with all older versions I tried so far.

What's wrong with my command?

[El Heggunte]

Try remuxing your "out.mkv" with MKVtoolnix. The Matroska muxer of ffmpeg is buggy, and probably the Matroska demuxer of ffplay is equivalently-buggy.

[rusmichal]

Got it. =P Thanks.

Anyway, I ended up writing my own script that uses neroAacEnc, x264 (executable) (level 3.1) and muxing their outputs to .mp4.