[vlc-devel] [PATCH] audio_filters: add sample converter in pipeline

[Thomas Guillem]

On Fri, Oct 30, 2015, at 16:24, Thomas Guillem wrote:
> 
> 
> On Fri, Oct 30, 2015, at 14:05, Thomas Guillem wrote:
> > 
> > On Fri, Oct 30, 2015, at 12:27, Rémi Denis-Courmont wrote:
> > > Le 2015-10-30 13:30, Thomas Guillem a écrit :
> > > > When creating a new chain a filter, the sample rate "audio converter" 
> > > > is not
> > > > added in the chain since a "audio resampler" is already added at the
> > > > end of the chain.
> > > 
> > > I think that is how it should be - except where the rate is known to 
> > > never change (e.g. unpaced sout).
> > 
> > In that case (unpaced sout), I think that the "/* Resample */" block
> > miss a aout_FormatPrepare (&output) to setup the
> > filter->fmt_out.audio.i_bytes_per_frame. Without that, resamplers "audio
> > converter" crashes.
> > 
> > > 
> > > Having two resamplers chained gives terrible results.
> > 
> > The two resamplers will be chained only when fixing a delay. Generally,
> > it happen less than 10seconds during a playback.
> > 
> > So, what should we do:
> >  - Having a good quality fixed resampler with good performances during
> >  the whole playback, and adding a ugly one to fix a delay (generally,
> >  less than 10seconds).
> >  - Having only one lower quality variable resampler.
> > 
> > > 
> > > > Unfortunately, we don't have any audio_filter modules that is capable
> > > > of doing a variable-rate resampling with good quality and good 
> > > > performances.
> > > 
> > > Hmm? SRC works fine here.
> > 
> > I'll do some test with fixed and variable rate with that one too. (I do
> > my test on Desktop and very old android devices).
> 
> SRC seems to be the best for variable sample rate, but it handles only
> float to float, that is useless for android.

One question, can the "audio resampler" filter be before the format
converter ?
If so, wan can use SRC on android (when the codec output float).

> 
> > 
> > > 
> > > -- 
> > > Rémi Denis-Courmont
> > > http://www.remlab.net/
> > > _______________________________________________
> > > vlc-devel mailing list
> > > To unsubscribe or modify your subscription options:
> > > https://mailman.videolan.org/listinfo/vlc-devel
> > _______________________________________________
> > vlc-devel mailing list
> > To unsubscribe or modify your subscription options:
> > https://mailman.videolan.org/listinfo/vlc-devel
> _______________________________________________
> vlc-devel mailing list
> To unsubscribe or modify your subscription options:
> https://mailman.videolan.org/listinfo/vlc-devel