good point about CBR... and this would require to get BufferSizeInKB
adjusted at the proper place, with InitialDelayInKB

On Tue, Nov 28, 2017 at 11:41 PM, Mark Thompson <[email protected]> wrote:

> On 01/12/17 20:04, Zhong Li wrote:
> > Hypothetical Reference Decoding (HRD) model assumes that data flows into
> a
> > buffer of the fixed size BufferSizeInKB with a constant bitrate.
> > BufferSizeInKB represents the maximum possible size of any compressed
> frames.
> >
> > Signed-off-by: Zhong Li <[email protected]>
> > ---
> >  libavcodec/qsvenc.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/libavcodec/qsvenc.c b/libavcodec/qsvenc.c
> > index 9db9eb3..cdddfd9 100644
> > --- a/libavcodec/qsvenc.c
> > +++ b/libavcodec/qsvenc.c
> > @@ -437,7 +437,7 @@ static int init_video_param(AVCodecContext *avctx,
> QSVEncContext *q)
> >      q->param.mfx.NumSlice           = avctx->slices;
> >      q->param.mfx.NumRefFrame        = FFMAX(0, avctx->refs);
> >      q->param.mfx.EncodedOrder       = 0;
> > -    q->param.mfx.BufferSizeInKB     = 0;
> > +    q->param.mfx.BufferSizeInKB     = (avctx->rc_buffer_size > 0) ?
> avctx->rc_buffer_size / 8000 : 0;
> >
> >      desc = av_pix_fmt_desc_get(sw_format);
> >      if (!desc)
> >
>
> The Intel documentation says "BufferSizeInKB represents the maximum
> possible size of any compressed frames.".  Is that just confused?  Some of
> the surrounding text does suggest that it's the right thing.
>
> Probably fine, but are you sure it should be set when in
> non-bitrate-targetted modes?  (The related HRD parameter InitialDelayInKB
> is set further down in CBR/VBR modes only.)
>
> - Mark
>
>
> Aside:  Please try to avoid sending messages from the future, it's
> confusing when things are sorted by time.  (You probably have the clock set
> wrong on a machine used for git send-email.)
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