[FFmpeg-devel] [PATCH] lavfi: add aselect audio variant of select

[Stefano Sabatini]

On date Wednesday 2012-12-12 10:25:03 +0100, Nicolas George encoded:
> Le primidi 21 frimaire, an CCXXI, Stefano Sabatini a écrit :
> > TODO: add Changelog entry, bump minor
> > ---
> >  doc/filters.texi         |   20 +++++++--
> >  libavfilter/Makefile     |    1 +
> >  libavfilter/allfilters.c |    1 +
> >  libavfilter/vf_select.c  |  106 +++++++++++++++++++++++++++++++++++++---------
> >  4 files changed, 104 insertions(+), 24 deletions(-)
> 

> Unless I am mistaken, it still works on a frame-by-frame basis. For video,
> this is normal, but for audio it is more of a problem: framing in audio
> filters is mostly random, and its effect can be a real problem for A-V sync.

Yes this works by selecting *frames*, and this is the expected
behavior, consistent with that of video select.

I expect this filter to be used mainly for two purposes:

1. drop frames depending on the initial timestamp
2. test FFmpeg (e.g. to simulate frame drop and test synching features)

For both purposes the filter seems well suited.

A more fine-grained select which filters each single sample
(sampleselect?) may be implemented, but I believe aselect should stay
the way it is for consistency with select.
-- 
FFmpeg = Formidable & Fanciful Meaningless Pitiless Evil Gem