[FFmpeg-devel] [PATCH] lavc/qsvenc: Set default bitrate to 2M

[Anton Khirnov]

Quoting Timo Rothenpieler (2023-12-06 13:26:51)
> On 06/12/2023 07:51, Xiang, Haihao wrote:
> > On Di, 2023-12-05 at 12:47 +0100, Timo Rothenpieler wrote:
> >> On 05.12.2023 09:15, Xiang, Haihao wrote:
> >>> From: Haihao Xiang <haihao.xiang at intel.com>
> >>>
> >>> 2M is suitable for more cases, e.g. 4K video.
> >>>
> >>> Signed-off-by: Haihao Xiang <haihao.xiang at intel.com>
> >>> ---
> >>>    libavcodec/qsvenc_av1.c   | 2 +-
> >>>    libavcodec/qsvenc_h264.c  | 2 +-
> >>>    libavcodec/qsvenc_hevc.c  | 2 +-
> >>>    libavcodec/qsvenc_mpeg2.c | 2 +-
> >>>    libavcodec/qsvenc_vp9.c   | 2 +-
> >>>    5 files changed, 5 insertions(+), 5 deletions(-)
> >>>
> >>> diff --git a/libavcodec/qsvenc_av1.c b/libavcodec/qsvenc_av1.c
> >>> index c697845d7b..78c92c1844 100644
> >>> --- a/libavcodec/qsvenc_av1.c
> >>> +++ b/libavcodec/qsvenc_av1.c
> >>> @@ -129,7 +129,7 @@ static const AVClass class = {
> >>>    };
> >>>    
> >>>    static const FFCodecDefault qsv_enc_defaults[] = {
> >>> -    { "b",         "1M"   },
> >>> +    { "b",         "2M"   },
> >>
> >> Wouldn't it be better to use a constant quality option as default,
> >> rather than a fixed bitrate?
> > 
> > Did you mean change the default bitrate control mode to CQP ? I was concerned
> > about the impact to current users.
> 
> Yeah, it's technically a breaking change.
> Though at least libx264 also at some point changed its default to a 
> reasonable medium quality crf mode, away from a fixed, rather low, bitrate.
> Not sure if that was done on a major bump, or if it was considered low 
> impact enough to just push out.

FYI we should have a major bump if the next few months (before 7.0).

So you could schedule the switch for then, ideally with a runtime
warning and perhaps a changelog entry.

-- 
Anton Khirnov