[FFmpeg-devel] [PATCH] avcodec: Add bits_per_raw_sample to AVCodecParameters

Michael Niedermayer michael at niedermayer.cc
Fri Apr 15 00:30:59 CEST 2016


On Tue, Apr 12, 2016 at 01:25:43PM +0200, wm4 wrote:
> On Tue, 12 Apr 2016 13:10:09 +0200
> Michael Niedermayer <michael at niedermayer.cc> wrote:
> 
> > On Mon, Apr 11, 2016 at 01:32:07AM +0200, Michael Niedermayer wrote:
> > > The bits_per_raw_sample represents the number of bits of precission per sample.
> > > 
> > > The field is added at the logical place, not at the end as the code was just
> > > recently added
> > > 
> > > This fixes the regression about loosing the audio sample precission information
> > > 
> > > The change in the fate test checksum un-does the change from the merge
> > > 
> > > Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> > > ---
> > >  libavcodec/avcodec.h |   17 +++++++++++++++++
> > >  libavcodec/utils.c   |    2 ++
> > >  tests/ref/lavf/ffm   |    2 +-
> > >  3 files changed, 20 insertions(+), 1 deletion(-)  
> > 
> > new version of this with improved documentation
> > I intend to apply this soon if noone is against
> > 
> > 
> > From e500d2222d31368b760144b1e2b5b094f73b571b Mon Sep 17 00:00:00 2001
> > From: Michael Niedermayer <michael at niedermayer.cc>
> > Date: Mon, 11 Apr 2016 00:52:21 +0200
> > Subject: [PATCH] avcodec: Add bits_per_raw_sample to AVCodecParameters
> > 
> > The bits_per_raw_sample represents the number of bits of precission per sample.
> > 
> > The field is added at the logical place, not at the end as the code was just
> > recently added
> > 
> > This fixes the regression about loosing the audio sample precission information
> > 
> > The change in the fate test checksum un-does the change from the merge
> > 
> > Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> > ---
> >  libavcodec/avcodec.h |   21 +++++++++++++++++++++
> >  libavcodec/utils.c   |    2 ++
> >  tests/ref/lavf/ffm   |    2 +-
> >  3 files changed, 24 insertions(+), 1 deletion(-)
> > 
> > diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
> > index b3655c5..99cbf88 100644
> > --- a/libavcodec/avcodec.h
> > +++ b/libavcodec/avcodec.h
> > @@ -3832,9 +3832,30 @@ typedef struct AVCodecParameters {
> >       */
> >      int64_t bit_rate;
> > 
> > +    /**
> > +     * The number of bits per sample in the codedwords.
> > +     *
> > +     * This is basically the bitrate per sample, it is mandatory for a bunch of
> > +     * formats to actually decode them, its the number of bits for one sample in
> 
> "It's". Also, add more full stops instead of creating long sentences.
> 
> > +     * the actual coded bitstream.
> > +     *
> > +     * This could be for example 4 for ADPCM
> > +     * For PCM formats this matches bits_per_raw_sample
> > +     * Can be 0
> > +     */
> >      int bits_per_coded_sample;
> > 
> >      /**
> > +     * The number of bits of precission in the samples.
> 
> Precision. Just get a spellchecker.
> 
> > +     *
> > +     * These are the bits in a decoded (raw) sample.
> 
> Maybe: "This is the number of valid bits in each output sample. If the
> sample format has more bits, the least significant bits are additional
> padding bits, which are always 0. Use right shifts to reduce the sample
> to its actual size. For example, audio formats with 24 bit samples will
> have bits_per_raw_sample set to 24, and format set to AV_SAMPLEFMT_S32.
> To get the original sample use "(uint32_t)sample >> 8"."
> 
> Don't know if this is good. (Also is it even correct? I forgot whether
> audio sample data uses negative values too.) Maybe this should be added
> to AVCodecContext too. It's a common point of confusion.

suggested changed made ad applied

ill submit a seperae patch for mentioning negative values

thanks

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I have never wished to cater to the crowd; for what I know they do not
approve, and what they approve I do not know. -- Epicurus
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