[FFmpeg-devel] [PATCH] Remove qmin and qmax constraints for nvenc vbr

Ganapathy Raman Kasi gkasi at nvidia.com
Fri Feb 24 04:01:07 EET 2017

Adding on to the previous mail,
To test this patch, please try :

i) ffmpeg -y -i $INPUT -vcodec h264_nvenc -preset medium $OUT_medium.mp4
ii) ffmpeg -y -i $INPUT -vcodec h264_nvenc -preset medium $OUT_slow.mp4

Without patch : $OUT_medium and $OUT_slow will be binary identical since both use NV_ENC_PARAMS_RC_VBR
With patch : $OUT_medium and $OUT_slow will be different and ii) will take more time to run and usually results in better quality. Thanks


-----Original Message-----
From: ffmpeg-devel [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf Of Ganapathy Raman Kasi
Sent: Thursday, February 23, 2017 5:42 PM
To: FFmpeg development discussions and patches <ffmpeg-devel at ffmpeg.org>
Subject: [FFmpeg-devel] [PATCH] Remove qmin and qmax constraints for nvenc vbr


qmin and qmax are not necessary for nvenc vbr. Enforcing this constraint, doesn't allow user to use vbr 2 pass mode (

NV_ENC_PARAMS_RC_2_PASS_VBR) without explicity setting the qmin and qmax options and reverts to the default vbr mode (

NV_ENC_PARAMS_RC_VBR). If needed user can still set qmin and qmax and those will be obeyed. Please review. Thanks.


Ganapathy Kasi

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