[FFmpeg-devel] [PATCH][RFC] avcodec/dpxenc: add option to force color transfer characteristics

[Kieran O Leary]

Hi Carl,

On Sat, Dec 16, 2017 at 2:31 PM, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
> 2017-12-15 22:22 GMT+01:00 Tobias Rapp <t.rapp at noa-archive.com>:
>
>> +    { "dpx_color_trc",  "Transfer Characteristics", OFFSET(color_trc), AV_OPT_TYPE_INT, { .i64 = DPX_TRC_UNDEFINED }, DPX_TRC_UNDEFINED, DPX_TRC_NB-1, VE, "trc" },
>
> This seems wrong to me, we have colour characteristics in general code.
>

There is a method in this patch that takes values from -color_trc, is
that not sufficient?

$ ./ffmpeg -f lavfi -i testsrc -color_trc bt709 -vframes 1 out.dpx &&
mediainfo out.dpx |tail -n 4

ffmpeg version N-90649-g9825f77 Copyright (c) 2000-2018 the FFmpeg developers

  built with Apple LLVM version 8.0.0 (clang-800.0.42.1)

  configuration:

  libavutil      56. 13.100 / 56. 13.100

  libavcodec     58. 17.100 / 58. 17.100

  libavformat    58. 11.101 / 58. 11.101

  libavdevice    58.  2.100 / 58.  2.100

  libavfilter     7. 14.100 /  7. 14.100

  libswscale      5.  0.102 /  5.  0.102

  libswresample   3.  0.101 /  3.  0.101

Input #0, lavfi, from 'testsrc':

  Duration: N/A, start: 0.000000, bitrate: N/A

    Stream #0:0: Video: rawvideo (RGB[24] / 0x18424752), rgb24,
320x240 [SAR 1:1 DAR 4:3], 25 tbr, 25 tbn, 25 tbc

File 'out.dpx' already exists. Overwrite ? [y/N] y

Stream mapping:

  Stream #0:0 -> #0:0 (rawvideo (native) -> dpx (native))

Press [q] to stop, [?] for help

Output #0, image2, to 'out.dpx':

  Metadata:

    encoder         : Lavf58.11.101

    Stream #0:0: Video: dpx, rgb24(unknown/unknown/bt709), 320x240
[SAR 1:1 DAR 4:3], q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc

    Metadata:

      encoder         : Lavc58.17.100 dpx

frame=    1 fps=0.0 q=-0.0 Lsize=N/A time=00:00:00.04 bitrate=N/A
speed=20.6x

video:227kB audio:0kB subtitle:0kB other streams:0kB global
headers:0kB muxing overhead: unknown

Color primaries                          : BT.709

Transfer characteristics                 : BT.709


Best,

Kieran.