#8119: mpeg2_vaapi encoder "QP" parameter for CQP
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Reporter: ahakon | Type:
| enhancement
Status: new | Priority: normal
Component: avcodec | Version: git-
Keywords: | master
vaapi_encode_mpeg2, cqp | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Summary of the bug:
When using the CQP Rate Control (-c:v mpeg2_vaapi -rc_mode CQP)
the current implementation only accepts the global_quality to configure
it. This value is set using the "-q:v" option, but this value isn't in the
common range 0-31 (in fact, 0.09 corresponds to 10, 0.1 to 11, etc.).
However, in the H.264 VAAPI encoder (h264_vaapi) the explicit parameter
"QP" exists. And this value sets the GENERIC VAAPI ENCODER value of
"explicit_qp". See:
https://github.com/FFmpeg/FFmpeg/blob/f30fb5ef626140d6e286a22e4f5ca7e7f5b97c67/libavcodec/vaapi_encode_h264.c#L1258
https://github.com/FFmpeg/FFmpeg/blob/f30fb5ef626140d6e286a22e4f5ca7e7f5b97c67/libavcodec/vaapi_encode_h264.c#L1236
So, only adding this "-qp" parameter to the MPEG2 VAAPI ENCODER, then it
will enable the option to use the common 0-31 range with this encoder. In
fact, a very small of new source lines are required. Just copy&paste!
Regards.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/8119>
FFmpeg <https://ffmpeg.org>
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