[FFmpeg-user] dynamically sync video and audio - is it possible?

[Feurstein, Michael]

Hi,


My testruns show that when muxing an incoming udp stream with another audio stream the video stream always seems to be delayed plus minus 2  seconds. Is there a way to dynamically sync audio and video, or maybe tell ffmpeg to start muxing when both video and audio are available. I reckon the dynamic delay comes from opening the streams, therefore I can't assume a 2 second delay for each run, because sometimes the delay will be 3 seconds. My goal would be to automate this.



I already tried itsoffset, which only helps if I know the delay beforehand, which I don't.



I've been playing around with vsync and async as well as isync, but without success. The manual tells me I can sync one part (video or audio) to another, only thing is I can't find a working command setup



Does someone out there have knowledge in how to use vsync and map the audio to the video? Maybe an example?

If not... is it even possible what I want to achieve?



I appreciate any input.



Thanks and greetings!

Michael Feurstein