“ffmpeg -i input -c:v libx264rgb output”: ffmpeg sets the color range to “tv” instead of “pc”

[Kdmeizk]

ffmpeg -h encoder=libx264rgb
Encoder libx264rgb [libx264 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 RGB]:
    General capabilities: delay threads 
    Threading capabilities: auto
    Supported pixel formats: bgr0 bgr24 rgb24

cat libavcodec/libx264.c
[…]
    x4->params.vui.b_fullrange = avctx->pix_fmt == AV_PIX_FMT_YUVJ420P ||
                                 avctx->pix_fmt == AV_PIX_FMT_YUVJ422P ||
                                 avctx->pix_fmt == AV_PIX_FMT_YUVJ444P ||
                                 avctx->color_range == AVCOL_RANGE_JPEG;

[Jun Zhao]

Pls try the patch: ​https://patchwork.ffmpeg.org/patch/16446/

[Jun Zhao]

Replying to mypopy:

Pls try the patch: ​https://patchwork.ffmpeg.org/patch/16446/

ignore the patch, you can change the color range like the command:

ffmpeg -i input -c:v libx264rgb -color_range pc output

[gdgsdg123]

What's the practical impact of this issue?..

I've tested some input sources with PNG and libx264rgb (without setting -color_range), all compare groups yielded a SSIM of 1.

[Balling]

And so what? FFmpeg does not support limited rgb, it is prohibited to use it. BTW, dumb. That is #1851

all compare groups yielded a SSIM of 1.

That is again just because see above. And BTW that does not happen anymore when input is gdigrub, for example. Fixed by Jan here ​https://github.com/FFmpeg/FFmpeg/commit/7ca71b79f2b3256a0eef1a099b857ac9e4017e36 and for x265 here ​https://github.com/FFmpeg/FFmpeg/commit/dbe40478e293f78c5a5e4302eb3f38257106ee86