[FFmpeg-devel] [PATCH v1 1/2] lavc/vp9: set yuvj pixel format for full range decode

Thilo Borgmann thilo.borgmann at mail.de
Mon Jun 19 11:14:02 EEST 2023

Am 18.06.23 um 23:21 schrieb Leo Izen:
> On 6/17/23 10:26, Thilo Borgmann wrote:
>> Am 17.06.23 um 16:02 schrieb Leo Izen:
>>> On 6/17/23 04:11, Thilo Borgmann wrote:
>>>> While the yuvj pixel formats are deprecated lots of code still relies
>>>> on them to be set. Without setting a yuvj420p pixel format VP9
>>>> decoding ends up incorrectly due to auto conversion.
>>> I oppose this on principle. If there's code that relies on YUVJ being set, 
>>> then *that code* needs to be changed so it respects the AVFrame->color_range 
>>> field. Which code is working improperly with this?
>> I don't like adding YUVJ stuff either. If I do
>>   ./ffmpeg -i full-range-in.mp4 -c:v libvpx-vp9 -lossless 1 lossless-out.mp4
>> and then comparing the frames, they are not equal. E.g. by
>>   ./ffmpeg -i full-range-in.mp4 -i lossless-out.mp4 -filter_complex ssim -f crc -
>> they are not 1.0 in ssim terms.
> Are you sure? I just tested a sample and found that I got exactly 1.0 in ssim 
> terms. Do you have a link to a sample for which this fails?

IIRC I had the same impression when testing, I think I mixed up patched and 
unpatched ffmpeg builds.

Anyway, happy you retest, I used

./ffmpeg -f lavfi -i testsrc=duration=10:size=1280x720:rate=30 -pix_fmt yuvj420p 
-color_range pc full-range-in.mp4

to generate my input sample. I cannot test myself again until Thursday, my 
Laptop is not equipped with libvpx.

Thank you!

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