[FFmpeg-devel] [PATCH 2/2] lavc/vaapi_encode: fix the mismatched vbvBuf size unit for mpeg2

[Fu, Linjie]

> -----Original Message-----
> From: ffmpeg-devel [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf
> Of Mark Thompson
> Sent: Thursday, January 24, 2019 07:38
> To: ffmpeg-devel at ffmpeg.org
> Subject: Re: [FFmpeg-devel] [PATCH 2/2] lavc/vaapi_encode: fix the
> mismatched vbvBuf size unit for mpeg2
> 
> On 16/01/2019 14:34, Linjie Fu wrote:
> > hrd_buffer_size and hrd_initial_buffer_fullness are set in bits, while
> > driver takes the vbvBuf size in 16 kbits. The mismatch will cause
> > quality issue.
> >
> > One way to solve this issue in FFmpeg level is set the bufsize
> > specially for mpeg2 as the unit of 16 kbits, and discard the default
> > CBR mode in driver.
> >
> > Fix the quality issue in #7650.
> >
> > Signed-off-by: Linjie Fu <linjie.fu at intel.com>
> > ---
> >  libavcodec/vaapi_encode.c | 8 +++++---
> >  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> The documentation is very clear that these values are all in bits -
> <https://github.com/intel/libva/blob/master/va/va.h#L2095-L2100>.
> 
> Sounds like a driver bug?
> 
> - Mark

Agree it should be fixed in driver level.
And PR has been sent: https://github.com/intel/media-driver/pull/495.