[FFmpeg-user] delay time in live ultrasound converter

[Roger Pack]

On Thu, Aug 22, 2019 at 3:16 PM Michael Koch
<astroelectronic at t-online.de> wrote:
>
> Hello Paul,
>
> > ffplay and using pipe gives you huge delay. By using mpv and filtergraph
> > directly you would get much lesser delay.
> > Default delay introduced by this filter is the one set by win_size in
> > number of samples, which is by default 4096.
> > If you need less delay even than this one and can not use lower win_size
> > because of lesser precision use amultiply solution which
> > inherently have 0 delay.
>
> In my test the FFT method has a shorter delay time than the amultiply
> method.
> I just found out that the delay can be minimized by setting
> -audio_buffer_size to a very small value (10ms).
> Delay is now about 0.5 seconds. Short enough to see and hear the bats
> simultaneously.

Se also https://trac.ffmpeg.org/wiki/DirectShow#BufferingLatency
GL! :)