Canon CR3 support.

[LebedevRI]

Though, until the production camera is actually released, and the full set of freely-licensed samples is contributed to the https://raw.pixls.us/, it won't be merged.

[LebedevRI]

Does not appear to be TIFF.
Appears to be ISO Media / ISO/IEC 14496-12.
The actual content of the 'mdat' box appears to be JPEG-ish, but not old-good lossless-JPEG, because it contains M_DQT (define-quantization-tables marker)

$ file canon_eos_m50_01.cr3  
canon_eos_m50_01.cr3: ISO Media

$ mpv canon_eos_m50_01.cr3
Playing: canon_eos_m50_01.cr3
 (+) Video --vid=1 (*) ( 6000x4000 1.000fps)
     Video --vid=2 (*) ( 1624x1080 1.000fps)
     Video --vid=3 (*) ( 6288x4056 1.000fps)
Failed to initialize a video decoder for codec ''.

[LebedevRI]

Hmm, ok, this is strange. Got the ISO Media parser working, and hooked-up dummy Cr3Decoder.
The mdat chunk is NOT lossless jpeg. But it just loads via libjpeg.
Those CR3 appear to be plain demosaiced JPEG's...
(Yes, this is an actual decoded image)

[LibRaw]

According to ffprobe, mdat chunk contains four substreams.
First one is, exactly, JPEG preview, so from libjpeg's point of view this is JPEG file + ~30Mb of garbage (real raw data + makernotes) on tail.

[LebedevRI]

Aha, thank you, that makes more sense. Let's see...

[LibRaw]

unfortunately, two data chunks (1624x1080 and 6288x4056, first one probably is low-res preview) are not lossless jpegs too :(

[LebedevRI]

(I'm still hoping they are JPEG w/arithmetic coding)

[LibRaw]

It does not looks like JPEG (e.g. no FF doubling).

[LebedevRI]

There are 0xFF0xFF sequences in files 05, 11, 19, (looking at the second half of the file in okteta hex editor)

[clanmills]

Thank you folks. I'm going to keep out of a discussion about the pixels and keep to my domain of metadata. Thanks to your comments, I've now heard of ffprobe.

822 rmills@rmillsmbp:~/gnu/github $ exiv2 -pR foo.jpg 
STRUCTURE OF JPEG FILE: foo.jpg
 address | marker       |  length | data
       0 | 0xffd8 SOI  
       2 | 0xffdb DQT   |     132 
     136 | 0xffc0 SOF0  |      17 
     155 | 0xffc4 DHT   |     418 
     575 | 0xffda SOS  
823 rmills@rmillsmbp:~/gnu/github $ ffprobe foo.jpg 
ffprobe version 3.4.1 Copyright (c) 2007-2017 the FFmpeg developers
  built with Apple LLVM version 9.0.0 (clang-900.0.39.2)
  configuration: --prefix=/opt/local --enable-swscale --enable-avfilter --enable-avresample --enable-libmp3lame --enable-libvorbis --enable-libopus --enable-librsvg --enable-libtheora --enable-libopenjpeg --enable-libmodplug --enable-libvpx --enable-libsoxr --enable-libspeex --enable-libass --enable-libbluray --enable-lzma --enable-gnutls --enable-fontconfig --enable-libfreetype --enable-libfribidi --disable-jack --disable-libopencore-amrnb --disable-libopencore-amrwb --disable-indev=jack --enable-opencl --disable-outdev=xv --enable-audiotoolbox --enable-videotoolbox --enable-sdl2 --mandir=/opt/local/share/man --enable-shared --enable-pthreads --cc=/usr/bin/clang --arch=x86_64 --enable-x86asm --enable-libx265 --enable-gpl --enable-postproc --enable-libx264 --enable-libxvid
  libavutil      55. 78.100 / 55. 78.100
  libavcodec     57.107.100 / 57.107.100
  libavformat    57. 83.100 / 57. 83.100
  libavdevice    57. 10.100 / 57. 10.100
  libavfilter     6.107.100 /  6.107.100
  libavresample   3.  7.  0 /  3.  7.  0
  libswscale      4.  8.100 /  4.  8.100
  libswresample   2.  9.100 /  2.  9.100
  libpostproc    54.  7.100 / 54.  7.100
Input #0, image2, from 'foo.jpg':
  Duration: 00:00:00.04, start: 0.000000, bitrate: 7605132 kb/s
    Stream #0:0: Video: mjpeg, yuvj422p(pc, bt470bg/unknown/unknown), 6000x4000, 25 tbr, 25 tbn, 25 tbc
824 rmills@rmillsmbp:~/gnu/github $ 

I'll work on the metadata. We've found the XMP data and I'm confident the Exif (and IPTC) data is in the Canon uuid box at the top of the file.

Later, I will investigate previews and ICC profiles.

[LebedevRI]

I'll work on the metadata. We've found the XMP data and I'm confident the Exif (and IPTC) data is in the Canon uuid box at the top of the file.
Later, I will investigate previews and ICC profiles.

Thank you, @clanmills! Sounds awesome! :)

[lclevy]

Phil Harvey exiftool 10.82 can parse Canon CR3
it seems there are at least 3 pictures: THMB, PRVW, and other in mdat

[lclevy]

for http://img.photographyblog.com/reviews/canon_eos_m50/photos/canon_eos_m50_01.cr3
mdat contains "trak" picture at 0x6d940, 0x37b030, 0x546c70, and TIFF metadata at 0x2565b98