[FFmpeg-user] slow encoding from raw rgb

Paul B Mahol onemda at gmail.com
Fri Nov 2 11:09:58 EET 2018

On 11/2/18, Daniel Oberhoff <danieloberhoff at googlemail.com> wrote:
> Am 18.10.18 um 12:13 schrieb Paul B Mahol:
>> On 10/18/18, Daniel Oberhoff <danieloberhoff at googlemail.com> wrote:
>>> Hello,
>>> So we are trying to encode raw rgb data from a pipe with ffmpeg. We
>>> found that ffmpeg implicitly converts the data to tv range bt601, which
>>> is suboptimal. Especially tv range loses more information than
>>> neccessary, also bt709 seems to be the better color space.
>>> We know we can fix this by adding -vf
>>> scale=out_color_matrix=bt709:out_range=pc. Unfortuntately thi makes
>>> encoding a lot slower (40 vs 60 fps) which effectively makes this
>>> approach too slow for us. Do yiz have any idea why this is the case?
>> That approach does not use slice threading.
> So what is the suggested way to do this? Or should we just accept that
> rgb encoding is either slow or suboptimal? Is this such a rare use-case?

I suggest to raise bounty to further improve swscale library.

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