[FFmpeg-user] ffmpeg MP4/x264 output colours change when input source is different resolution (bug?)

[Dan]

On Thu, 15 Sep 2022 12:07:08 +0100, Michael Koch <astroelectronic at t-online.de> wrote:

> Am 15.09.2022 um 11:53 schrieb Dan:
>>> This seems to work with VLC player:
>>>
>>> ffmpeg -f lavfi -i color=0x19be0f:s=400x576 -colorspace bt709 -crf 0
>>> -vcodec libx264 -t 5 -y out1.mp4
>>> ffmpeg -f lavfi -i color=0x19be0f:s=400x578 -colorspace bt709 -crf 0
>>> -vcodec libx264 -t 5 -y out2.mp4
>>
>> Unfortunately, doesn't work for me in MPC or Chrome. Can you try a
>> height of 720 instead of 578 to see if that fails for you?
>
> Please try this, for me it works with VLC player, the color is exactly
> the same:
>
> ffmpeg -f lavfi -i color=0x19be0f:s=400x576 -colorspace bt709
> -color_primaries bt709 -color_trc bt709 -crf 0 -vcodec libx264 -t 5 -y
> out1.mp4
> ffmpeg -f lavfi -i color=0x19be0f:s=400x720 -colorspace bt709
> -color_primaries bt709 -color_trc bt709 -crf 0 -vcodec libx264 -t 5 -y
> out2.mp4

Sure.

The colour is both the same now (for both Chrome and MPC), except it's
the darker, wrong colour (green=164 instead of 190).

Dan