Question
FMSIS 3.5 recording delay
Hello from Poland,
We are working on some kind of karaoke application based on FMS IS 3.5. Trying to do it very right way we try to mix recorded voice ( or voice + video ) with prerecorded song ( flv file stored on server ) using sox and ffmpeg to join files and convert formats. Normally, the workflow with any session looks like this:
1. background song is played ( and paused at start ) by rtmp -> we wait untill it is cached totally, then
2. we record stream from mic ( or mic + camera )
3. recording is mixed with background on server-side, so we have nice one file to publish to other users.
And there is a problem. Recording seems always to be delayed to prerecorded background. After some research, trimming ( with sox ) about 300-350ms form recording beginning solves the problem, but not for all cases. Sometimes, this value seems to be too small or too big - and lack of synchronization can be clearly heard.
What can be the cause of this delay? Is it network issue, FMS issue orhardware ( soundcard, mic )? Is there any way to find value of this delay?
We are working on some kind of karaoke application based on FMS IS 3.5. Trying to do it very right way we try to mix recorded voice ( or voice + video ) with prerecorded song ( flv file stored on server ) using sox and ffmpeg to join files and convert formats. Normally, the workflow with any session looks like this:
1. background song is played ( and paused at start ) by rtmp -> we wait untill it is cached totally, then
2. we record stream from mic ( or mic + camera )
3. recording is mixed with background on server-side, so we have nice one file to publish to other users.
And there is a problem. Recording seems always to be delayed to prerecorded background. After some research, trimming ( with sox ) about 300-350ms form recording beginning solves the problem, but not for all cases. Sometimes, this value seems to be too small or too big - and lack of synchronization can be clearly heard.
What can be the cause of this delay? Is it network issue, FMS issue orhardware ( soundcard, mic )? Is there any way to find value of this delay?
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