[Cin] "color hell"
Andrew Randrianasulu
randrianasulu at gmail.com
Wed Jul 14 00:22:56 CEST 2021
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 fir screenshot) Oremiere 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..
>
>
>> 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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