[FFmpeg-devel] [PATCH] deprecate SAMPLE_FMT_S24

Michael Niedermayer michaelni
Tue Aug 19 15:31:52 CEST 2008


On Tue, Aug 19, 2008 at 10:29:32PM +1000, Peter Ross wrote:
> On Sun, Aug 17, 2008 at 05:10:39PM +0200, Michael Niedermayer wrote:
> > On Sun, Aug 17, 2008 at 04:37:49PM +0200, Aurelien Jacobs wrote:
> > > Michael Niedermayer wrote:
> > > 
> > > > On Sun, Aug 17, 2008 at 03:32:30PM +0200, Aurelien Jacobs wrote:
> > > > > Peter Ross wrote:
> > > > > 
> > > > > > This patch flags SAMPLE_FMT_S24 as deprecated.
> > > > > 
> 
> > bits_per_sample can NOT be used as SAMPLE_FMT_* bit count.
> > It has a different and docuented purpose, it describes the coded bitstream
> > and not the decoded samples, they match in bits only for lossless codecs.
> > 
> > example:
> > the a demuxer sets bits_per_sample to 4 and passes the data to a ADPCM
> > decoder which has SAMPLE_FMT_S16 output with 13 significant bits the
> > last 3 being always 0
> 
> Thanks for taking the time to explain this. Revised patch within.
> 
> The proposed field make sense only for SAMPLE_FMT_S32. I've kept the language
> generic, as it will have future utility when FFmpeg can manipulate 12/16-bit
> luma planes.

i think that maybe a
bits_per_coded_sample   // the number of bits in which each sample is coded
and
bits_per_raw_sample     // the number of bits in each PCM sample

would be better names, they are IMHO more clear
Iam not even sure that bits_per_sample is not sometimes used with the
expecttation that it is bits_per_raw_sample ...

I wonder if anyone would complain if we just renamed bits_per_sample to
bits_per_coded_sample ? It doesnt break ABI, just API of apps accessing it
without AVOptions and apps really should be using AVOptions

besides your patch is missing an update to the AVOption table in utils.c

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

Why not whip the teacher when the pupil misbehaves? -- Diogenes of Sinope
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