On Mon, Apr 11, 2016 at 11:29 AM, wm4 <nfx...@googlemail.com> wrote: > On Mon, 11 Apr 2016 03:12:20 +0200 > Michael Niedermayer <mich...@niedermayer.cc> wrote: > >> On Sun, Apr 10, 2016 at 11:39:57PM +0000, Kieran Kunhya wrote: >> > On Mon, 11 Apr 2016 at 00:33 Michael Niedermayer <mich...@niedermayer.cc> >> > 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 <mich...@niedermayer.cc> >> > > --- >> > > libavcodec/avcodec.h | 17 +++++++++++++++++ >> > > libavcodec/utils.c | 2 ++ >> > > tests/ref/lavf/ffm | 2 +- >> > > 3 files changed, 20 insertions(+), 1 deletion(-) >> > > >> > > diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h >> > > index b3655c5..87739d7 100644 >> > > --- a/libavcodec/avcodec.h >> > > +++ b/libavcodec/avcodec.h >> > > @@ -3832,9 +3832,26 @@ typedef struct AVCodecParameters { >> > > */ >> > > int64_t bit_rate; >> > > >> > > + /** >> > > + * The number of bits per sample in the codedwords. >> > > + * >> > > + * This is basically the bitrate per sample >> > > + * >> > > + * 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. >> > > + * >> > > + * For ADPCM this might be 12 or 16 or similar >> > > + * Can be 0 >> > > + */ >> > > + int bits_per_raw_sample; >> > > >> > > >> > Precision spelt wrong. Also needs more clarification as to the difference >> > between the two >> >> on one side of a bitstream format there is raw pcm data (raw samples) >> and on the other a compressed bitstream (aka coded samples) >> these 2 where intended to specify the number of bits per sample in >> these 2 representations >> >> i really dont know how to word this so that its clear and everyone >> understands it >> >> >> > - I have no idea what the difference is or why one would >> > use bits_per_coded_sample for anything. >> >> bits_per_coded_sample is used by several codecs (huffyuv, ima adpcm, >> ...) in avi as a single byte extradata. so it must be transported from >> the demuxer (avi headers) to the decoder and encoder to muxer >> to make this worse, in some of these codecs it matches the >> bits_per_raw_sample, in some it does not > > I still don't understand. bits_per_coded_sample is part of the > AVCodecParameters struct. So what's the difference between per_coded > and per_raw? >
As I understand it, coded is mandatory for a bunch of formats to actually decode it, ie. the number of bits for one sample in the actual coded bitstream. And raw is just the bits in a decoded (raw) sample. Sometimes those two can be the same, especially if the codec in question doesnt have a concept of coded bits per sample. - Hendrik _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel