add support for Kodak PhotoCD image format

[ami_stuff]

​ftp://ftp.kodak.com/www/images/pcd/0795image01.pcd

some patches were posted here (currently unavailable):

https://ffmpeg.org/pipermail/ffmpeg-devel/2010-January/086658.html
https://ffmpeg.org/pipermail/ffmpeg-devel/2010-January/086778.html

C:\>ffmpeg -i C:\0795image01.pcd
ffmpeg version N-81755-g267da70 Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 4.5.0 (GCC) 20100414 (Fedora MinGW 4.5.0-1.fc14)
  configuration: --prefix=/var/www/users/research/ffmpeg/snapshots/build --arch=
x86 --target-os=mingw32 --cross-prefix=i686-pc-mingw32- --cc='ccache i686-pc-min
gw32-gcc' --enable-pthreads --enable-memalign-hack --enable-runtime-cpudetect --
enable-cross-compile --enable-static --disable-shared --extra-libs='-lws2_32 -lw
inmm -lpthread' --extra-cflags='--static -I/var/www/users/research/ffmpeg/snapsh
ots/build/include' --extra-ldflags='-static -L/var/www/users/research/ffmpeg/sna
pshots/build/lib' --enable-bzlib --enable-zlib --enable-gpl --enable-version3 --
enable-nonfree --enable-libx264 --enable-libspeex --enable-libtheora --enable-li
bvorbis --enable-libfaac --enable-libxvid --enable-libopencore-amrnb --enable-li
bopencore-amrwb --enable-libmp3lame --enable-libfreetype --enable-libvpx --disab
le-decoder=libvpx
  libavutil      55. 30.100 / 55. 30.100
  libavcodec     57. 58.100 / 57. 58.100
  libavformat    57. 50.100 / 57. 50.100
  libavdevice    57.  0.102 / 57.  0.102
  libavfilter     6. 63.100 /  6. 63.100
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  1.100 /  2.  1.100
  libpostproc    54.  0.100 / 54.  0.100
C:\0795image01.pcd: Invalid data found when processing input

[Carl Eugen Hoyos]

PhotoCD image decoder: Patch by Kenneth Vermeirsch

[Carl Eugen Hoyos]

Photocd YCC->RGB colorspace conversion: Patch by Kenneth Vermeirsch, kavermei at gmail

[Elon Musk]

Where are images now?

[Carl Eugen Hoyos]

The image linked above is now in ​http://samples.ffmpeg.org/ffmpeg-bugs/trac/ticket5923/

[Carl Eugen Hoyos]

Patch applied by Paul in c8e38950e3aad0304ec861aa4985b866dceddc7c

[Balling]

This is incorrect, Paul. The colorspace used is not AVCOL_TRC_IEC61966_2_1, it is AVCOL_TRC_IEC61966_2_4 (or xvYCC). That is TransferCharacteristics 11 per H.273. That is what ​https://www5.in.tum.de/lehre/vorlesungen/graphik/info/csc/COL_34.htm says and that is what wikipedia says (albeit with a problem in 0.099 v. 0.99). ​https://en.wikipedia.org/wiki/Photo_CD Again, there is a perfect sample here: ​http://www.tedfelix.com/PhotoCD/REFIMAGE.PCD that should look like described in ​http://www.tedfelix.com/PhotoCD/pcd-102.pdf

I suppose without proper support for Superwhite YUV headroom, there is no way to present this correctly. And that also requires compatible YUV TV. There is a idea of HDR images, of course (those are also clarified in pcd-102 above).

Also, 64Base (4096 × 6144) is not implemented. It was implemented here in February 2020. ​https://sourceforge.net/projects/pcdtojpeg/files/pcdtojpeg/pcdtojpeg%201.0.14/ (source code inside).

It is very important to get this correctly because the very famous Kodak test images have highest quality in that format. ​https://www.math.purdue.edu/~lucier/PHOTO_CD/IMAGES/ (the same as ​https://samples.ffmpeg.org/ffmpeg-bugs/trac/ticket5923/demo/)

[Elon Musk]

Please refrain from opening this ticket, if you have anything useful to provide, like 4k samples, than go ahead. Thanks.

[Balling]

Why? The spec is also here. xvYCC is used ​http://scarse.sourceforge.net/docs/kodak/pcd-045.pdf here some more values ​http://scarse.sourceforge.net/docs/kodak/pcd-042.pdf and others.

Also even if you do some convertions (though I cannot see it, sorry ;( ) I suppose ffprobe should report AVCOL_TRC_IEC61966_2_4 that is supported after all...