[Matroska-users] Convert mkv to mp4 - audio video sync issue

Bachman Kharazmi bahkha at gmail.com
Sun Nov 22 19:11:11 CET 2009


Hi
Anyone who knows if mp4 container format is troublesome to get lipsync with?

I have big problems with audio/video out of sync when writing
audio/video streams to a mp4muxer. I can successfully use a
matroskamuxer instead and the a/v are
perfectly synced. I have with such video even tried to do conversion
(demux and mux) from mkv container to mp4 using mencoder and
gst-mp4mux, and it didn't help. Still sync problems in the mp4 output
:(

The video is h264 and audio is AAC.
Please see mkvinfo at the end of this email.

The gst-launch line I tested with is:
gst-launch -v filesrc location=out.mkv ! matroskademux name=d mp4mux
name=m ! filesink  location=foo.mp4 d.video_00 ! queue ! m.video_00
d.audio_00 ! queue ! m.audio_00
And mencoder like:
mencoder out.mkv -of lavf -lavfopts format=mp4 -oac lavc -ovc lavc -o outfoo.mp4

I know that mkvextract can extract track1,track2,timestamps. Are there
any free linux tools that can take them as input and properly put it
in a mp4 container?

Other ideas and hints are welcome as well.
/B

--- MKVINFO:

+ EBML head
|+ Doc type: matroska
|+ Doc type version: 1
|+ Doc type read version: 1
+ Segment, size unknown
|+ Seek head (subentries will be skipped)
|+ Segment information
| + Segment UID: 0xbf 0x50 0x64 0xa3 0xbb 0x01 0xd6 0x8e 0x65 0xb0
0x8a 0x0d 0x5d 0x0e 0xb9 0xeb
| + Timecode scale: 1000000
| + Duration: 0.000s (00:00:00.000000000)
| + Muxing application: GStreamer plugin version 0.10.17.1
| + Writing application: GStreamer Matroska muxer
| + Date: Fri Nov 20 17:16:16 2009 UTC
|+ Segment tracks
| + A track
|  + Track number: 1
|  + Track type: audio
|  + Track UID: 16220852567616579723
|  + Audio track
|   + Sampling frequency: 16000.000000
|  + Codec ID: A_AAC/MPEG4/LC
|  + Name: Audio
| + A track
|  + Track number: 2
|  + Track type: video
|  + Track UID: 14929359976084277804
|  + Default duration: 33.333ms (30.000 fps for a video track)
|  + Video track
|   + Pixel width: 640
|   + Pixel height: 480
|  + Codec ID: V_MPEG4/ISO/AVC
|  + CodecPrivate, length 33
|  + Name: Video
|+ Cluster



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