On Fri, Aug 14, 2015 at 07:37:08AM +0200, Sven Dueking wrote: > > > > -----Ursprüngliche Nachricht----- > > Von: ffmpeg-devel [mailto:ffmpeg-devel-boun...@ffmpeg.org] Im Auftrag > > von Michael Niedermayer > > Gesendet: Donnerstag, 13. August 2015 17:41 > > An: FFmpeg development discussions and patches > > Cc: Sven Dueking > > Betreff: Re: [FFmpeg-devel] [PATCH] Changed max bitrate for VBV mode > > (according to Ivan Uskow) > > > > On Thu, Aug 13, 2015 at 11:30:45AM +0100, Sven Dueking wrote: > > > From: Sven Dueking <s...@nablet.com> > > > > > > --- > > > libavcodec/qsvenc.c | 6 +++++- > > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > > > diff --git a/libavcodec/qsvenc.c b/libavcodec/qsvenc.c index > > > 57f5fe4..b56e4b4 100644 > > > --- a/libavcodec/qsvenc.c > > > +++ b/libavcodec/qsvenc.c > > > @@ -118,10 +118,14 @@ static int init_video_param(AVCodecContext > > > *avctx, QSVEncContext *q) > > > > > > switch (q->param.mfx.RateControlMethod) { > > > case MFX_RATECONTROL_CBR: > > > + q->param.mfx.InitialDelayInKB = avctx- > > >rc_initial_buffer_occupancy / 1000; > > > + q->param.mfx.TargetKbps = avctx->bit_rate / 1000; > > > + q->param.mfx.MaxKbps = avctx->bit_rate / 1000; > > > + break; > > > case MFX_RATECONTROL_VBR: > > > q->param.mfx.InitialDelayInKB = avctx- > > >rc_initial_buffer_occupancy / 1000; > > > q->param.mfx.TargetKbps = avctx->bit_rate / 1000; > > > - q->param.mfx.MaxKbps = avctx->bit_rate / 1000; > > > + q->param.mfx.MaxKbps = avctx->rc_max_rate / 1000; > > > > why is rc_max_rate not used for MFX_RATECONTROL_CBR ? > > Hi Michael, > > Ivan is on vacation and I did the fix according to his last command : > > "This correct for MFX_RATECONTROL_CBR but a bug for MFX_RATECONTROL_VBR. > Will fixed later. For any case part of ratecontrol setup should be > re-designed to support more advanced LA rate contol" > > The Intel Documentation states that : > > For variable bitrate control, the MaxKbps parameter specifies the maximum > bitrate at which the encoded data enters the Video Buffering Verifier (VBV) > buffer. > > And for CBR the target bitrate and max bitrate should be equal to archive a > bitrate that is near a desired target for streaming (no peaks etc.)
In the code there is this:
} else if (avctx->rc_max_rate == avctx->bit_rate) {
q->param.mfx.RateControlMethod = MFX_RATECONTROL_CBR;
ratecontrol_desc = "constant bitrate (CBR)";
assuming thats how CBR is set, the variables are equal and the special
case is not needed
am i missing something ?
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
The misfortune of the wise is better than the prosperity of the fool.
-- Epicurus
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