[Libav-user] sws_scale - "Warning: data is not aligned!" when using opencv::Mat

Wodzu brucedickinson at wp.pl
Sat Dec 22 20:40:50 EET 2018

> First, I meant you can only remove the conversion if you verified that the
> range of your input is the same (mpeg range) as the range expected by your
> h264 encoder.

What do you mean by "range"?

> Second, if you are using libx264, it nowadays accepts gray8 as input (instead
> of yuv420p), if you use it, there should be no additional steps necessary, you
> pass the gray8 frames to libx264.

When I set my context->pix_fmt = AV_PIX_FMT_GRAY8 then I get [libx264 @ 000000000037d9c0] Specified pixel format gray is invalid or not supported.

I am using build: ffmpeg-4.0-win64-shared. libavcodec version is 58.18.100. Is this too old version for the support of 8 bit gray images out of the box?

Best regards,


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