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

Leo Izen leo.izen at gmail.com
Thu Feb 13 01:24:08 CET 2014


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.

Then, looking at libx265's output, it says

x265 [info]: Rate Control / AQ-Strength / CUTree : ABR-200 kbps / 1.0 / 1

which matches FFmpeg's default of 200k.

Full, uncut output available at http://pastebin.com/iQPHAj4h

Am I doing something incorrectly, or is this a bug?


Leo Izen

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