[FFmpeg-user] libx265 (HEVC) encoding CRF issue

[Lou]

On Wed, 12 Feb 2014 19:24:08 -0500
Leo Izen <leo.izen at gmail.com> wrote:

> Hello,
> 
> I noticed that FFmpeg recently added libx265 as a supported library to 
> git master. I'm trying to encode a video I have as HEVC with FFmpeg, but 
> CRF encoding doesn't seem to work the way it does with libx264. (x265's 
> CLI supports CRF).
> 
> When I try to run FFmpeg with
> 
> ffmpeg -i bbb3d_sunflower_ffvhuff.mkv -c:v libx265 -preset:v veryslow 
> -crf:v 15 bbb3d_sunflower_hevc.mkv
> 
> this appears as a warning:
> 
> Codec AVOption crf (Select the quality for constant quality mode) 
> specified for output file #0 (bbb3d_sunflower_hevc.mkv) has not been 
> used for any stream. The most likely reason is either wrong type (e.g. a 
> video option with no video streams) or that it is a private option of 
> some encoder which was not actually used for any stream.

Use:
-preset veryslow -x265-params crf=15

-crf has not yet been mapped as a private option for libx265.