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

[Michael Niedermayer]

On Fri, Apr 15, 2016 at 12:38:23PM +0200, wm4 wrote:
> On Fri, 15 Apr 2016 00:06:27 -0300
> James Almer <jamrial at gmail.com> wrote:
> 
> > On 4/14/2016 7:30 PM, Michael Niedermayer wrote:
> > > 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  
> > 
> > Should the change made to matroskaenc be reverted then? It was changed from
> > using bits_per_raw_sample to bits_per_coded_sample in the codecpar commit
> > because the former wasn't available back then.
> > 
> 
> Yep.

change made

i forgot about it totally

thx


[...]
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