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

Ganapathy Raman Kasi gkasi at nvidia.com
Thu Mar 2 01:15:55 EET 2017


Thanks for review. If qmin and qmax are not set, nvenc will assume default of qmin 15 and qmax 51 which is good enough for most content. Setting qmin 5 would be similar to qmin of 15 at lower bitrates as ratecontrol may not  reach below QP 15. 

Ganapathy

-----Original Message-----
From: ffmpeg-devel [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf Of Philip Langdale
Sent: Tuesday, February 28, 2017 5:54 AM
To: Miroslav Slugeň <thunder.m at email.cz>
Cc: FFmpeg development discussions and patches <ffmpeg-devel at ffmpeg.org>
Subject: Re: [FFmpeg-devel] [PATCH] Remove qmin and qmax constraints for nvenc vbr

On Tue, 28 Feb 2017 11:54:32 +0100
Miroslav Slugeň <thunder.m at email.cz> wrote:

> Dne 28.2.2017 v 10:44 Timo Rothenpieler napsal(a):
> > Am 28.02.2017 um 01:24 schrieb Ganapathy Raman Kasi:  
> >> Can someone please help review patch. Thanks.  
> > I have seen an marked it, but I don't have time to review and test 
> > stuff right now.
> > Will get to it eventually.
> > _______________________________________________
> > ffmpeg-devel mailing list
> > ffmpeg-devel at ffmpeg.org
> > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> I tested this patch, it looks like there is no difference when you set 
> -qmin 5 -qmax 51 or leave it unset.
> 
> BUT this patch is correct, NVENC doesn't require QMIN and QMAX for 
> 2pass vbr.
> 
> M.
> 
> 
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> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel

Patch looks good to me too. Timo, I can push it if you don't mind not testing it yourself.


--phil
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