[FFmpeg-devel] How to drop audio samples?

Richard Neill rn214
Wed May 16 22:07:09 CEST 2007

Dear Stefan,

Thanks for your advice.

> Richard Neill schreef:
>> Thanks very much - that's very helpful. How do I ensure that the audio
>> timestamps are correct? What's the best way to view the timestamps and
>> check them?
>> I've tried with various values of -async, up to 440, and it doesn't seem
>> to help, so I suspect that the camera is generating timestamps which are
>> false. I'm using a file captured thus:

I've done another capture, and find the following

   dvgrab - > test.dv    #capture 2 hours

   mplayer test.dv	#is fine, all the way through
   vlc test.dv		#looses sync

   usr/local/bin/ffmpeg -f dv -i test.dv -vcodec mpeg4 -b 512000 -async 
50 -acodec ac3 -ab 128000 -f mpegts ffmpegtest.avi

   mplayer ffmpeg.avi	#looses sync quite quickly.

> Can you check if VideoLAN Client is able to maintain A/V sync?

No, it isn't.

Any other suggestions?

> In the past we had a lot of problem like this *suddenly* everything
> worked in VideoLAN. If this works for you too it could be interesting to
> check what they fix or better: how they fix it.

Thanks very much,


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