[FFmpeg-user] aresample filter stretch usage [async]

Jamie Jellicoe jamiejellicoe at gmail.com
Thu Apr 25 12:09:05 CEST 2013


Hi,

I am trying to transcode a ts file to an mp4 for playback in a web browser.

There are some damaged video frames in the ts file so with the default
ffmpeg options the resultant mp4 contains an edits list to show where
frames have been dropped.

Unfortunately, most browser media player plugins do not recognise edits
lists and therefore the mp4 is out of sync (audio-video) when played in a
browser.

According to the ffmpeg docs I should be using the option
'aresample=async=1000' to:
'Stretch/squeeze samples to the given timestamps, with a maximum of 1000
samples per second compensation:', this is exactly the behaviour I require,
however, I get this error:

[AVFilterGraph @ 0x22dae20] Error initializing filter 'aresample' with args
'async=1000'
Error opening filters!

When I use aresample=44100 the filter seems to initialise ok but the mp4 is
out of sync.

The full command I am using is:

ffmpeg -i d152.ts -af aresample=async=1000 -y d152.mp4

Any help would be greatly appreciated.

Many Thanks in advance, Jamie


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