[Cin] "color hell"

Andrew Randrianasulu randrianasulu at gmail.com
Wed Jul 14 02:18:34 CEST 2021 

On Wednesday, July 14, 2021, Andrew Randrianasulu <randrianasulu at gmail.com>
wrote:

>
>
> On Tuesday, July 13, 2021, Andrew Randrianasulu <randrianasulu at gmail.com>
> wrote:
>
>>
>>
>> On Tuesday, July 13, 2021, Phyllis Smith <phylsmith2017 at gmail.com> wrote:
>>
>>> Andrew, I really like the "color hell" moniker.
>>> Andrea, you are right, ffprobe shows it correctly.  I had always heard
>>> that mediainfo sometimes got it wrong, but this is the first time I saw
>>> that.
>>>
>>> What about old projects? will they handle this change correctly?
>>>
>>
>>
>> I tried to add my new colorspace as numbered define  _after_ all pre-used
>> defines, while renaming old bt601 to bt601 ntsc (given usual ntsc-centered
>> preference in other parts of cin)
>>
>> and of course _order_ in preferences mattered,  my patches made things
>> shift down by one (so displayed colorspace and encoded colorspace drifted
>> by one! bt2020 displayed was real bt601 pal... bt601 ntsc was bt709... as
>> you sharply noted!)
>>
>> I think we save it per-session (in Cinelerra_rc) not per-project? will
>> look more into it...
>>
>> try add two more patches I attached? one is fix another is comment.
>>
>> Also, while we are here may be rename and enlarge  bt2020  label for
>> bt2020 *nc* as code (in ffmpeg.C) seems to map it really?
>>
>
>
> according to this page (scroll down for screenshot) Premiere
> differenciates between bt2020 ncl and bt2020 cl :
>
> https://www.voukoder.org/forum/thread/487-hdr-support-
> in-x265-and-nvenc-hevc/
>
> for now I just enlarged dropdown menu a bit..
>


 added 2020 ncl/cl diff + hopefully mapping between (rare) ffmpeg's
floating-point pix formats and Cinelerra's rgb(a) float...

fixed typos in prev mail...



>
>
>>
>>
>>> On Tue, Jul 13, 2021 at 12:17 PM Andrew Randrianasulu <
>>> randrianasulu at gmail.com> wrote:
>>>
>>>>
>>>>
>>>> On Tuesday, July 13, 2021, Phyllis Smith via Cin <
>>>> cin at lists.cinelerra-gg.org> wrote:
>>>>
>>>>> Not so sure about that after running more tests.
>>>>> Using 601Pal, mediainfo reports BT.601.
>>>>> Using 601Ntsc, medinao reports BT.709 !!
>>>>> As always, have to make sure old projects still work.
>>>>>
>>>>
>>>>
>>>> its called color hell for this exact reason)
>>>>
>>>> may be mediainfo a bit wrong (at least ver. you used - shoukd be recent
>>>> on Fedora, but small fixes like this can go in anytime...)
>>>>
>>>> see confusing code at (should be recent enough from 2020)
>>>>
>>>> https://sourceforge.net/p/mediainfo/discussion/297610/thread
>>>> /0b6d2fd38f/?limit=25
>>>>
>>>> =====
>>>>
>>>> ha.
>>>>
>>>> //----------------------------------------------------------
>>>> -----------------
>>>> extern const char* Mpegv_colour_primaries(int8u colour_primaries)
>>>> {
>>>>     switch (colour_primaries)
>>>>     {
>>>>         case 1 : return "BT.709";
>>>>         case 4 : return "BT.470 System M";
>>>>         case 5 : return "BT.601 PAL";
>>>>         case 6 : return "BT.601 NTSC";
>>>>         case 7 : return "SMPTE 240M"; //Same as BT.601 NTSC
>>>>         case 8 : return "Generic film";
>>>>         case 9 : return "BT.2020"; //Added in HEVC
>>>>         case 10 : return "XYZ"; //Added in HEVC 2014
>>>>         case 11 : return "DCI P3"; //Added in HEVC 2016
>>>>         case 12 : return "Display P3"; //Added in HEVC 2016
>>>>         case 22 : return "EBU Tech 3213"; //Added in HEVC 2016
>>>>         default : return "";
>>>>     }
>>>> }
>>>>
>>>> //----------------------------------------------------------
>>>> -----------------
>>>> extern const char* Mpegv_transfer_characteristics(int8u
>>>> transfer_characteristics)
>>>> {
>>>>     switch (transfer_characteristics)
>>>>     {
>>>>         case 1 : return "BT.709"; //Same as BT.601
>>>>         case 4 : return "BT.470 System M";
>>>>         case 5 : return "BT.470 System B/G";
>>>>         case 6 : return "BT.601";
>>>>         case 7 : return "SMPTE 240M";
>>>>         case 8 : return "Linear";
>>>>         case 9 : return "Logarithmic (100:1)"; //Added in MPEG-4 Visual
>>>>         case 10 : return "Logarithmic (316.22777:1)"; //Added in MPEG-4
>>>> Visual
>>>>         case 11 : return "xvYCC"; //Added in AVC
>>>>         case 12 : return "BT.1361"; //Added in AVC
>>>>         case 13 : return "sRGB/sYCC"; //Added in HEVC
>>>>         case 14 : return "BT.2020 (10-bit)"; //Same a BT.601 //Added in
>>>> HEVC, 10/12-bit difference is in ISO 23001-8
>>>>         case 15 : return "BT.2020 (12-bit)"; //Same a BT.601 //Added in
>>>> HEVC, 10/12-bit difference is in ISO 23001-8
>>>>         case 16 : return "PQ"; //Added in HEVC 2015
>>>>         case 17 : return "SMPTE 428M"; //Added in HEVC 2015
>>>>         case 18 : return "HLG"; //Added in HEVC 2016
>>>>         default : return "";
>>>>     }
>>>> }
>>>>
>>>> //----------------------------------------------------------
>>>> -----------------
>>>> extern const char* Mpegv_matrix_coefficients(int8u matrix_coefficients)
>>>> {
>>>>     switch (matrix_coefficients)
>>>>     {
>>>>         case 0 : return "Identity"; //Added in AVC
>>>>         case 1 : return "BT.709";
>>>>         case 4 : return "FCC 73.682";
>>>>         case 5 : return "BT.470 System B/G";
>>>>         case 6 : return "BT.601"; //Same as BT.470 System B/G
>>>>         case 7 : return "SMPTE 240M";
>>>>         case 8 : return "YCgCo"; //Added in AVC
>>>>         case 9 : return "BT.2020 non-constant"; //Added in HEVC
>>>>         case 10 : return "BT.2020 constant"; //Added in HEVC
>>>>         case 11 : return "Y'D'zD'x"; //Added in HEVC 2016
>>>>         case 12 : return "Chromaticity-derived non-constant"; //Added
>>>> in HEVC 2016
>>>>         case 13 : return "Chromaticity-derived constant"; //Added in
>>>> HEVC 2016
>>>>         case 14 : return "ICtCp"; //Added in HEVC 2016
>>>>         default : return "";
>>>>     }
>>>> }
>>>>
>>>> =====
>>>>
>>>> note _transfer characteristics_ #1 said to be the same for bt. 709 and
>>>> #6  bt. 601! (in comment)
>>>>
>>>> can you post full mediainfo output for input video, and three other
>>>> videos: unmodded Cin, modded and  set to BT601 NTSC, set to BT601 pal?
>>>>
>>>>
>>>>>
>>>>> On Mon, Jul 12, 2021 at 2:26 PM Andrew Randrianasulu via Cin <
>>>>> cin at lists.cinelerra-gg.org> wrote:
>>>>>
>>>>>> According to
>>>>>>
>>>>>> https://kdenlive.org/en/project/color-hell-ffmpeg-transcodin
>>>>>> g-and-preserving-bt-601/
>>>>>>
>>>>>> bt 601 pal and bt 601 ntsc are  slightly different, I tried to update
>>>>>> CinGG's definitions so now she have two distinct 601 colorspaces, but I
>>>>>> still can be wrong (esp on kr, kb coeffecients)
>>>>>>
>>>>>> can anyone test patch 3 and see if it makes any positive difference?
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Cin mailing list
>>>>>> Cin at lists.cinelerra-gg.org
>>>>>> https://lists.cinelerra-gg.org/mailman/listinfo/cin
>>>>>>
>>>>>
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