[vlc-devel] [RFC-PATCH] core/audio_output: do not drop (late) audio blocks if it would cause silence

[Rémi Denis-Courmont]

On Tuesday 17 May 2016 20:52:46 Filip Roséen wrote:
> > Since we got functionality in order to support resampling (to shrink the
> > drift while maintaining playback), it should probably be used under
> > circumstances as what is mentioned; or well, that was what went through
> > my head when I wrote the patch.
> > 
> > The duration is just as much part of the entity as the PTS, and if one is
> > used to make decisions about potentially discarding the entity itself,
> > I'd say it is equally safe to use the other.
> > 
> > 
> > The decision could however be improved by also incorporating
> > AOUT_MAX_PTS_DELAY to actually discard blocks that we need to shrink
> > (resample over time) to a lower duration than AOUT_MAX_PTS_DELAY (ie.
> > preferring silence instead of a longer period of resampling).
> > 
> > My experiments has however showed that the gain is neglectable with my
> > sample files (at least to the human ear), but in theory it could be an
> > improvement.
> Regarding what Remi wrote in the reply linked below, do we have some other
> ideas (besides what has been proposed in the patch in question) that could
> solve this issue?
> 
>   - https://mailman.videolan.org/pipermail/vlc-devel/2016-May/107673.html
> 
> Given that the patch solves a few of our the issues (and tickets) we are
> currently facing regarding broken audio when seeking/audio running late; I
> would love for a solution to the problem.

It is very debatable that this improves the user experience. For music, 
resampling sounds absolutely terrible. Dropping on seek is not an issue since 
a glitch is bound to occur when seeking.

-- 
Rémi Denis-Courmont
http://www.remlab.net/