[FFmpeg-devel] [RFC] libavfilter audio API and related issues

Michael Niedermayer michaelni
Mon Apr 5 21:01:14 CEST 2010


On Mon, Apr 05, 2010 at 07:49:14PM +0200, Stefano Sabatini wrote:
> On date Monday 2010-04-05 16:54:18 +0200, Michael Niedermayer encoded:
> > only a few quick comments
> > 
> > On Mon, Apr 05, 2010 at 01:55:43PM +0200, Stefano Sabatini wrote:
> > > Follow some notes about a possible design for the audio support in
> > > libavfilter.
> > > 
> > > AVFilterSamples struct 
> > > ======================
> > > 
> > > (Already defined in afilters, but renamed AVFilterBuffer at some
> > > point.)
> > > 
> > > Follows a possible definition (with some differences whit respect to
> > > that currently implemented in afilters):
> > > 
> > > typedef struct AVFilterSamples
> > > {
> > >     uint8_t *data;
> > 
> > missing suport for planar formats
> > also the structs are very similar to existing structs, do we really
> > want new structs for each stream type?
> > file position missing, it was possibly added later to the video
> > structs and forgotten to be added to audio because it has seperate
> > structs
> 
> I see the point, but then there are some specific fields which are
> only meaningful for audio (sample_rate) and video (w, h, pixel_aspect).
> 
> Also data[4]/linesize[4] is going to work only with samples with no
> more than four channel, av_audio_convert supports up to 6 channels.

s/4/8/


> 
> Also we may need more enum SampleFormat, now we have (avcodec.h):
> 
> /**
>  * all in native-endian format
>  */
> enum SampleFormat {
>     SAMPLE_FMT_NONE = -1,
>     SAMPLE_FMT_U8,              ///< unsigned 8 bits
>     SAMPLE_FMT_S16,             ///< signed 16 bits
>     SAMPLE_FMT_S32,             ///< signed 32 bits
>     SAMPLE_FMT_FLT,             ///< float
>     SAMPLE_FMT_DBL,             ///< double
>     SAMPLE_FMT_NB               ///< Number of sample formats. DO NOT USE if dynamically linking to libavcodec
> };
> 
> I wonder if we should support LE/BE variants like it is done with PCM

no


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No great genius has ever existed without some touch of madness. -- Aristotle
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