[FFmpeg-user] Audio/video stream are out of sync?

[christina zou]

Carl,

I spent a lot of time trying to use ffmpeg alone (alsa/v4l2), but it
produces extreme stuttering on the audio track. Using my approach of
writing to named pipes and sending those into ffmpeg, I add a bit of
latency but ensure that there's no loss of frames. This was the approach
suggested to me by the ffmpeg IRC channel. I'm on a Pi Zero (single core),
by the way.

Is there any way to align the two input streams' timestamps, if they are
both being read from named pipes?

Here is my full console output: http://pastebin.com/phmiphaL

Thanks,
Christina



On Wed, Feb 8, 2017 at 3:02 PM, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:

> 2017-02-08 22:57 GMT+01:00 christina zou <zou.christina at gmail.com>:
>
> > *arecord -Dmic_sv -c2 -r48000 -fS32_LE -twav temp_audio.v & \*
>
> Why?
> (See below)
>
> > *raspivid -fps 10 -v -b 3000000 -o temp_video.h264 -t 0 & \*
>
> Is this not possible with ffmpeg alone?
>
> > ~/special/ffmpeg/ffmpeg* \*
> > *    -framerate 10 \*
> > *    -re \*
> > *    -i temp_video.h264 \*
> > *    -i temp_audio.v \*
>
> (Complete, uncut console output missing.)
> How are these two input streams supposed to be synced?
>
> Normally, you would use (for example) alsa and v4l2 input
> and hope that the two drivers both provide wallclock timestamps.
>
> Carl Eugen
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