[FFmpeg-devel] [PATCH V2 1/3] libavcodec/vaapi_decode: fix the problem that init_pool_size < nb_surface

Chen, Wenbin wenbin.chen at intel.com
Fri Dec 10 04:54:10 EET 2021


> Quoting Wenbin Chen (2021-11-30 09:44:04)
> > For vaapi if the init_pool_size is not zero, the pool size is fixed.
> > This means max surfaces is init_pool_size, but when mapping vaapi
> > frame to qsv frame, the init_pool_size < nb_surface. The cause is that
> > vaapi_decode_make_config() config the init_pool_size and it is called
> > twice. The first time is to init frame_context and the second time is to
> > init codec. On the second time the init_pool_size is changed to original
> > value so the init_pool_size is lower than the reall size because
> > pool_size used to initialize frame_context need to plus thread_count and
> > 3 (guarantee 4 base work surfaces). Now add code to make sure
> > init_pool_size is only set once. Now the following commandline works:
> >
> > ffmpeg -hwaccel vaapi -hwaccel_device /dev/dri/renderD128 \
> > -hwaccel_output_format vaapi -i input.264 \
> > -vf "hwmap=derive_device=qsv,format=qsv" \
> > -c:v h264_qsv output.264
> >
> > Signed-off-by: Wenbin Chen <wenbin.chen at intel.com>
> > ---
> >  libavcodec/vaapi_decode.c | 34 ++++++++++++++++++----------------
> >  1 file changed, 18 insertions(+), 16 deletions(-)
> >
> > diff --git a/libavcodec/vaapi_decode.c b/libavcodec/vaapi_decode.c
> > index 665af370ed..aab8162989 100644
> > --- a/libavcodec/vaapi_decode.c
> > +++ b/libavcodec/vaapi_decode.c
> > @@ -572,22 +572,24 @@ static int
> vaapi_decode_make_config(AVCodecContext *avctx,
> >          if (err < 0)
> >              goto fail;
> >
> > -        frames->initial_pool_size = 1;
> > -        // Add per-codec number of surfaces used for storing reference
> frames.
> > -        switch (avctx->codec_id) {
> > -        case AV_CODEC_ID_H264:
> > -        case AV_CODEC_ID_HEVC:
> > -        case AV_CODEC_ID_AV1:
> > -            frames->initial_pool_size += 16;
> > -            break;
> > -        case AV_CODEC_ID_VP9:
> > -            frames->initial_pool_size += 8;
> > -            break;
> > -        case AV_CODEC_ID_VP8:
> > -            frames->initial_pool_size += 3;
> > -            break;
> > -        default:
> > -            frames->initial_pool_size += 2;
> > +        if (!frames->initial_pool_size) {
> > +            frames->initial_pool_size = 1;
> > +            // Add per-codec number of surfaces used for storing reference
> frames.
> > +            switch (avctx->codec_id) {
> > +            case AV_CODEC_ID_H264:
> > +            case AV_CODEC_ID_HEVC:
> > +            case AV_CODEC_ID_AV1:
> > +                frames->initial_pool_size += 16;
> > +                break;
> > +            case AV_CODEC_ID_VP9:
> > +                frames->initial_pool_size += 8;
> > +                break;
> > +            case AV_CODEC_ID_VP8:
> > +                frames->initial_pool_size += 3;
> > +                break;
> > +            default:
> > +                frames->initial_pool_size += 2;
> > +            }
> 
> Seems to me that ff_vaapi_decode_init() should not pass hw_frames_ctx to
> vaapi_decode_make_config() at all, because it is already initialized and
> must not be modified.
> 
> --
> Anton Khirnov

You are right. I don't need to add an new check. ff_vaapi_decode_init() should pass NULL
to vaapi_decode_make_config. Thanks for your review. I will submit a new patch

Regards
Wenbin
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