[FFmpeg-devel] [PATCH 1/2] Add additional color spaces and transfer characteristics defined in H.264

[Michael Niedermayer]

On Tue, Jan 05, 2010 at 01:00:44AM -0500, David Conrad wrote:
> On Jan 4, 2010, at 8:36 PM, Michael Niedermayer wrote:
> 
> > On Mon, Jan 04, 2010 at 08:00:21PM -0500, David Conrad wrote:
> >> On Jan 4, 2010, at 7:48 PM, Michael Niedermayer wrote:
> >> 
> >>> On Mon, Jan 04, 2010 at 07:12:09PM -0500, David Conrad wrote:
> >>>> ---
> >>>> libavcodec/avcodec.h |    8 ++++++++
> >>>> 1 files changed, 8 insertions(+), 0 deletions(-)
> >>>> 
> >>>> diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
> >>>> index c982a64..20d07a0 100644
> >>>> --- a/libavcodec/avcodec.h
> >>>> +++ b/libavcodec/avcodec.h
> >>>> @@ -475,6 +475,13 @@ enum AVColorTransferCharacteristic{
> >>>>    AVCOL_TRC_UNSPECIFIED=2,
> >>>>    AVCOL_TRC_GAMMA22    =4, ///< also ITU-R BT470M / ITU-R BT1700 625 PAL & SECAM
> >>>>    AVCOL_TRC_GAMMA28    =5, ///< also ITU-R BT470BG
> >>> 
> >>>> +    AVCOL_TRC_SMPTE170M  =6, ///< equivalent to 1
> >>> 
> >>> if its equivalent to 1 adding it has little sense
> >> 
> >> It's the same sort of thing as AVCOL_PRI_SMPTE170M vs. AVCOL_PRI_SMPTE240M but it can be ignored.
> > 
> > hmm, i see we already have duplicates, in that case feel free to add
> > this one
> > 
> > 
> >> 
> >>> +    AVCOL_TRC_SMPTE240M  =7,
> >>>> +    AVCOL_TRC_LINEAR     =8,
> >>>> +    AVCOL_TRC_LOG100     =9, ///< logarithmic, 100:1 range
> >>>> +    AVCOL_TRC_LOG316     =10,///< logarithmic, 316.22777:1 range
> >>>> +    AVCOL_TRC_IEC61966   =11,///< IEC 61966-2-4
> >>>> +    AVCOL_TRC_BT1361_EXT =12,///< ITU-R BT1361 extended gamut
> >>>>    AVCOL_TRC_NB           , ///< Not part of ABI
> >>>> };
> >>>> 
> >>>> @@ -486,6 +493,7 @@ enum AVColorSpace{
> >>>>    AVCOL_SPC_BT470BG    =5, ///< also ITU-R BT601-6 625 / ITU-R BT1358 625 / ITU-R BT1700 625 PAL & SECAM / IEC 61966-2-4 xvYCC601
> >>>>    AVCOL_SPC_SMPTE170M  =6, ///< also ITU-R BT601-6 525 / ITU-R BT1358 525 / ITU-R BT1700 NTSC / functionally identical to above
> >>>>    AVCOL_SPC_SMPTE240M  =7,
> >>>> +    AVCOL_SPC_YCgCo      =8, ///< reversable YUV as defined in H.264
> >>>>    AVCOL_SPC_NB           , ///< Not part of ABI
> >>>> };
> >>> 
> >>> are these used by anyone in practice?
> >>> if no, then i see no sense in adding them
> >> 
> >> YCgCo is iirc the only colorspace in JPEG-XR. Everything else, probably not.
> > 
> > so new question
> > is JPEG-XR used by anyone in practice?
> 
> Not as far as I can tell, I really had to hunt to find any samples when I briefly considered writing a decoder.

thought so
also, if we do implement a decoder it might return RGB instead of
YCgCo. There may be various reasons for this, like that RGB might fit
in 8bit per component while YCgCo might need 9 thus effectively 16
see our ljpeg code for an example of this

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

He who knows, does not speak. He who speaks, does not know. -- Lao Tsu
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