Correcting Video Levels

Patrick Cusack patrickcusack at
Sat May 14 14:37:36 UTC 2022

Can you indulge me a little thought experiment? Would it be possible to use another tool to write yup frames to a socket that GStreamer then uses as input? Or can you direct me to a plugin example where I cold do the calculations my self?



> On May 13, 2022, at 1:47 PM, Nicolas Dufresne via gstreamer-devel <gstreamer-devel at> wrote:
> Le jeudi 12 mai 2022 à 07:57 -0700, Patrick Cusack via gstreamer-devel a écrit :
>> GStreamer team,
>> I am capturing video using a BlackMagic Video device, sending out using a VP9
>> encoder, and then using a payloader for use with webRTC. When I view the
>> stream, my blacks and whites are mapped 16-235 instead of 0-255. Is there a
>> way to correct this? WIth ffmpeg, I can use a filter graph and and set the
>> input and output scale “scale=in_range=limited:out_range=limited”.
> I don't think our converters current handle this, but the range is part of the
> colorimetry= filed in caps. Would be nice to fix this of course, range
> conversion seems pretty handy.
>> Thanks,
>> Patrick

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