[MPlayer-users] Screenshot color wrong

[Polyphem]

Dear Team,

for certain mp4 files the screenshot color seems to be wrong for me, there
is a slight red-shift in color. I think this has something to do with pixel
format and/or colorspace, but sadly I couldn't figure out a solution.

I tried several combinations of -something like "-vf
scale,format=rgb24,screenshot", in fact I tried all possible solutions, in
vain.

Documentation says for the screenshot filter "E.g. it should be the last
filter if you want to have an exact screenshot of what you see on the
monitor.", sadly that's not the case for me here. Running on Win10 with
nvidia graphic card.


MPlayer sherpya-r38188+g6e1903938b-10-win32 (C) 2000-2020 MPlayer Team

Playing c:\test\test.mp4
libavformat version 58.44.100 (internal)
libavformat file format detected.
[mov,mp4,m4a,3gp,3g2,mj2 @ 000000000232e340]Protocol name not provided,
cannot determine if input is local or a network protocol, buffers and
access patterns cannot be configured optimally without knowing the protocol
[lavf] stream 0: audio (aac), -aid 0, -alang und
[lavf] stream 1: video (h264), -vid 0
VIDEO:  [H264]  1014x1376  24bpp  50.000 fps  13944.4 kbps (1702.2 kbyte/s)
Opening video filter: [screenshot]
==========================================================================
Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
libavcodec version 58.90.100 (internal)
Selected video codec: [ffh264] vfm: ffmpeg (FFmpeg H.264)
==========================================================================
Clip info:
 major_brand: mp42
 minor_version: 0
 compatible_brands: mp42isomavc1
 creation_time: 2018-10-08T14:18:19.000000Z
Load subtitles in c:\test\
Load subtitles in C:/Program Files
(x86)/AMT/AMT_Binaries/MPlayer-generic-r38188_x64/mplayer/sub/
==========================================================================
Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders
AUDIO: 48000 Hz, 6 ch, floatle, 317.4 kbit/3.44% (ratio: 39673->1152000)
Selected audio codec: [ffaac] afm: ffmpeg (FFmpeg AAC (MPEG-2/MPEG-4 Audio))
==========================================================================
AO: [dsound] 48000Hz 2ch s16le (2 bytes per sample)
Starting playback...
Movie-Aspect is 0.74:1 - prescaling to correct movie aspect.
[swscaler @ 00000000025fbdc0]bicubic scaler, from yuv420p to rgb24 using
MMXEXT
[swscaler @ 00000000025fbdc0]using unscaled yuv420p -> rgb24 special
converter
VO: [direct3d] 1014x1376 => 1014x1376 Planar YV12



Additional ffprobe.exe shows for the file:
pix_fmt=yuv420p
color_space=bt709


I guess there's some magic done here:
[swscaler @ 00000000025fbdc0]bicubic scaler, from yuv420p to rgb24 using
MMXEXT
[swscaler @ 00000000025fbdc0]using unscaled yuv420p -> rgb24 special
converter
which is not reflected in the screenshot filter. Is it possible to manually
add a similar conversion to the screenshot filter?

Thanks for any hints and with Best Regards