使用GStreamer播放mp4文件时同步音频和视频

Question

I need to sync video and audio when I play mp4 file. How can I do that?

Here's my pipeline:

gst-launch-0.10 filesrc location=./big_buck_bunny.mp4 ! \
    qtdemux name=demux demux.video_00 ! queue ! TIViddec2 engineName=codecServer codecName=h264dec ! ffmpegcolorspace !tidisplaysink2 video-standard=pal display-output=composite \
    demux.audio_00 ! queue max-size-buffers=500 max-size-time=0 max-size-bytes=0 ! TIAuddec1 ! audioconvert ! audioresample ! autoaudiosink

Answer 1

Have you tried playing the video on a regular desktop without using TI's elements? GStreamer should take care of synchronization for playback cases (and many others).

If the video is perfectly synchronized on a desktop then you have a bug on the elements specific to your target platform (TIViddec2 and tidisplaysink2). qtdemux should already put the expected timestamps on the buffers, so it is possible that TIViddec2 isn't copying those to its decoded buffers or tidisplaysink2 isn't respecting them. (The same might apply to the audio part)

I'd first check TIViddec2 by replacing the rest of the pipeline after it with a fakesink and run with verbose mode of gst-launch. The output from fakesink should show you the output timestamps, check if those are consistent, you can also put a fakesink right after qtdemux to check the timestamps that it produces and see if the decoders are respecting that.

Answer 2

我实际上使用了错误的视频帧率。