Help: ffmux_mov and mp4 Audio/Video out of sync question

Song, Yingsheng yisong at
Thu Jul 4 02:29:47 PDT 2013

Hi all,

I have been reluctant to post this message for quite a while.  I'm even struggling to describe the issue properly. For various reason we are still using the "ancient" ffmux_mov with GStreamer 1.0 and it is not feasible for us to upgrade to the latest GStreamer version so as to use mp4mux etc at this stage. I am afraid that I may talk to you in a different planet (guess not many people still using GStreamer 1.0 and ffmux_mov). Apologies if I posted to the wrong place.

We use ffmux_mov to generate mp4 clip from recorded raw frame data. The problem is that the mp4 file (video&audio) gradually gets out of sync from beginning to the end when played with VLC and WMP, but it was OK with QT. We have been suffering with this problem for a long time and have to reduce clip length to limit the impact.

I'm wondering if anyone using ffmux_mov has ever seen similar issue before. What sort of issue it may be from your point of view, considering it is OK for QT, but not for WMP and VLC.  I tried to adjust various VLC settings, but I couldn't find a way to get it work as QT. Is it a player issue or a MP4 generating issue?  Are you aware anything inside the ffmux_mov code that I may tune up to improve the A/V sync?

I can confirm that the recorded raw frame data is OK as the audio/video is in sync from any point of time at the beginning.

I understand my question is not so specific as other questions here and I am ready to provide anything you need in order for you to help me.

Any clue/advice would be highly appreciated.

Kind regards,



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