[FFmpeg-trac] #7070(swscale:new): A proper way of converting yuvj420p colorspace to yuv420p (AVC to HEVC reencoding)

[FFmpeg]

#7070: A proper way of converting yuvj420p colorspace to yuv420p (AVC to HEVC
reencoding)
---------------------------------+----------------------------------
             Reporter:  birdie   |                     Type:  defect
               Status:  new      |                 Priority:  minor
            Component:  swscale  |                  Version:  3.2.4
             Keywords:           |               Blocked By:
             Blocking:           |  Reproduced by developer:  0
Analyzed by developer:  0        |
---------------------------------+----------------------------------
 This is not a bug, this is a request for help.

 My phone generates files (AVC) in the yuvj420p colorspace and I cannot
 figure out how to reencode them to HEVC without losing colors.

 I have encoded 1) without options and I've also tried 2) this and 3) this:
 {{{
 ffmpeg -i src -vf "scale=in_range=pc:out_range=tv" out
 }}}
 and this
 {{{
 ffmpeg -i src -pix_fmt yuv420p -vf "scale=in_range=pc:out_range=tv" out
 }}}

 But I always get this warning message:

 {{{
 [swscaler @ 0x1229940] deprecated pixel format used, make sure you did set
 range correctly
 }}}

 And the resulting file always has different colors (either undersaturated
 (1) or oversatured (2,3) ).

 {{{
 ffprobe src.mp4
 ffprobe -i part0*mp4
 ffprobe version 3.4.2 Copyright (c) 2007-2018 the FFmpeg developers
   built with gcc 7 (GCC)
   configuration: --disable-static --enable-nonfree --enable-avfilter
 --enable-shared --enable-gpl --enable-postproc --enable-pthreads --enable-
 libspeex --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-
 libopus --enable-libopenjpeg --disable-debug --disable-doc --enable-
 libpulse --extra-cflags='-march=native' --enable-version3 --enable-
 libvorbis --enable-libfdk-aac --enable-gnutls --enable-libfreetype
 --enable-libx265 --libdir=/usr/local/lib64 --enable-lto
   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
   libswscale      4.  8.100 /  4.  8.100
   libswresample   2.  9.100 /  2.  9.100
   libpostproc    54.  7.100 / 54.  7.100
 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'part0.mp4':
   Metadata:
     major_brand     : isom
     minor_version   : 512
     compatible_brands: isomiso2avc1mp41
     encoder         : Lavf57.83.100
   Duration: 00:00:31.60, start: 0.014000, bitrate: 19315 kb/s
     Stream #0:0(eng): Video: h264 (Baseline) (avc1 / 0x31637661),
 yuvj420p(pc, smpte170m), 1920x1080, 19988 kb/s, SAR 1:1 DAR 16:9, 20.51
 fps, 20 tbr, 90k tbn, 180k tbc (default)
     Metadata:
       handler_name    : VideoHandler
     Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz,
 stereo, fltp, 96 kb/s (default)
     Metadata:
       handler_name    : SoundHandler
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/7070>
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