Hi On Sunday 10 July 2005 15:21, Erik Slagter wrote:
On Sun, 2005-07-10 at 12:43 +0200, Michael Niedermayer wrote:
does '-async 50' help?
Now can you please please please tell us what this options does and what's the meaning of the parameter?
it "stretches/sqeezes" the audio stream to match the timestamps, the parameter is the maximum samples per second by which the audio is changed
Interesting. Does it do that by resampling the audio?
yes
Also interesting that -async 1 can make the difference between having and not having a/v sync.
async 1 is a special case where only the start of the audio stream is corrected without any later correction
And what does vsync do, then?
vsync is similar, if its not 0 then video will be stretched/sqeezed to match the timestamps, allthough its done by duplicating and droping frames and with -map you can select from which stream the timestamps should be taken so you can leave either video or audio unchanged and sync the remaining stream(s) to the unchanged one if you want -- Michael