[FFmpeg-user] DNG images

Michael Koch astroelectronic at t-online.de
Tue Oct 13 23:06:37 EEST 2020

Am 11.10.2020 um 21:07 schrieb Michael Koch:
> Am 11.10.2020 um 20:56 schrieb Paul B Mahol:
>> On Sun, Oct 11, 2020 at 07:37:25PM +0200, Michael Koch wrote:
>>> I tested all 4 DNG images again with the latest FFmpeg version 
>>> (Gyan's build
>>> from today).
>>> I tested with and without zscale filter. All tests failed. When 
>>> testing with
>>> IrfanView, all DNG input images seem to be ok.
>> Your issues is that you do not know how to use zscale properly.
>> DNG decoding is just fine, what is missing is colorspace stuff in 
>> swscale,
>> for proper display.
> Can you please give an example for the correct zscale options?

Finally I found a command line that converts DNG (from Adobe DNG 
converter) to JPG with a more or less acceptable result:

ffmpeg -i IMG_3459.dng -vf 
-y out.jpg

But I think everything after "zscale" is only a dirty workaround to 
correct errors that were made somewhere else. Especially the strong 
amplification by factor 64 and strong color correction doesn't look 
right. Please also note that the size of the output image is wrong. It's 
bigger than the input image and has black borders at the left and top. 
The console output is below.


C:\Users\astro\Desktop\dng>c:\ffmpeg\ffmpeg -i IMG_3459.dng -vf 
-y out.jpg
ffmpeg version 2020-10-11-git-7ea4bcff7b-full_build-www.gyan.dev 
Copyright (c) 2000-2020 the FFmpeg developers
   built with gcc 10.2.0 (Rev3, Built by MSYS2 project)
   configuration: --enable-gpl --enable-version3 --enable-static 
--disable-w32threads --disable-autodetect --enable-fontconfig 
--enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp 
--enable-lzma --enable-libsnappy --enable-zlib --enable-libsrt 
--enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray 
--enable-libcaca --enable-sdl2 --enable-libdav1d --enable-libzvbi 
--enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264 
--enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg 
--enable-libvpx --enable-libass --enable-frei0r --enable-libfreetype 
--enable-libfribidi --enable-libvidstab --enable-libvmaf 
--enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid 
--enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va 
--enable-dxva2 --enable-libmfx --enable-libglslang --enable-vulkan 
--enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt 
--enable-libopencore-amrwb --enable-libmp3lame --enable-libshine 
--enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc 
--enable-libilbc --enable-libgsm --enable-libopencore-amrnb 
--enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa 
--enable-libbs2b --enable-libflite --enable-libmysofa 
--enable-librubberband --enable-libsoxr --enable-chromaprint
   libavutil      56. 60.100 / 56. 60.100
   libavcodec     58.111.100 / 58.111.100
   libavformat    58. 62.100 / 58. 62.100
   libavdevice    58. 11.102 / 58. 11.102
   libavfilter     7. 87.100 /  7. 87.100
   libswscale      5.  8.100 /  5.  8.100
   libswresample   3.  8.100 /  3.  8.100
   libpostproc    55.  8.100 / 55.  8.100
[tiff @ 000001d36e8cf800] Assuming black level pattern values are identical
[tiff @ 000001d36e8cf800] Tiled TIFF is not allowed to strip
[tiff_pipe @ 000001d36e8cd800] Stream #0: not enough frames to estimate 
rate; consider increasing probesize
Input #0, tiff_pipe, from 'IMG_3459.dng':
   Duration: N/A, bitrate: N/A
     Stream #0:0: Video: tiff, bayer_rggb16le, 5568x3708, 25 tbr, 25 
tbn, 25 tbc
Stream mapping:
   Stream #0:0 -> #0:0 (tiff (native) -> mjpeg (native))
Press [q] to stop, [?] for help
[tiff @ 000001d36e8d4900] Assuming black level pattern values are identical
[tiff @ 000001d36e8d4900] Tiled TIFF is not allowed to strip
[swscaler @ 000001d3706eed40] deprecated pixel format used, make sure 
you did set range correctly
[tonemap @ 000001d36e901040] Missing color space information, 
desaturation is disabled
[tonemap @ 000001d36e900240] Missing color space information, 
desaturation is disabled
Output #0, image2, to 'out.jpg':
     encoder         : Lavf58.62.100
     Stream #0:0: Video: mjpeg, yuvj444p(pc), 5568x3708, q=2-31, 200 
kb/s, 25 fps, 25 tbn, 25 tbc
       encoder         : Lavc58.111.100 mjpeg
     Side data:
       cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: N/A
frame=    1 fps=0.5 q=12.1 Lsize=N/A time=00:00:00.04 bitrate=N/A 
video:853kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB 
muxing overhead: unknown

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