[Mesa-dev] [PATCH 3/4] st/va: properly set max number of reference frames

[Christian König]

On 19.11.2015 10:37, Julien Isorce wrote:
> It fixes asserts like assert(templ->max_references <= 2) in
> nvc0_video.c::nvc0_create_decodier
> This patch also post-update the correct value for the number
> of reference frames in the h264 case, see below.
>
> In VA-API the max num ref is retrieved later in handlePictureParameterBuffer.
> Unfortunately by this time the decoder has been already created
> in vaCreateContextwhich which one does not have any max_references
> param compared to VDPAU api.
>
> In vdpau-driver they delay the decoder creation to endPicture.
> This is not practicable with gallium. But that's ok our buffer
> will be bigger but at least they will have enough space and
> st/va will still write correct value for the number of reference
> frames in the hw buffer.

Why is delaying the decoder creation till you know all the parameters 
not practical here?

Adjusting an internal parameter after the decoder was created sounds 
rather awkward to me.

Regards,
Christian.


>
> Signed-off-by: Julien Isorce <j.isorce at samsung.com>
> ---
>   src/gallium/state_trackers/va/context.c | 10 +++++++---
>   src/gallium/state_trackers/va/picture.c |  1 +
>   2 files changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/src/gallium/state_trackers/va/context.c b/src/gallium/state_trackers/va/context.c
> index ec9e048..b3dd293 100644
> --- a/src/gallium/state_trackers/va/context.c
> +++ b/src/gallium/state_trackers/va/context.c
> @@ -248,10 +248,14 @@ vlVaCreateContext(VADriverContextP ctx, VAConfigID config_id, int picture_width,
>         templat.max_references = num_render_targets;
>         templat.expect_chunked_decode = true;
>   
> +      /* XXX HEVC ? */
>         if (u_reduce_video_profile(templat.profile) ==
> -        PIPE_VIDEO_FORMAT_MPEG4_AVC)
> -        templat.level = u_get_h264_level(templat.width, templat.height,
> -                             &templat.max_references);
> +         PIPE_VIDEO_FORMAT_MPEG4_AVC) {
> +         templat.level = u_get_h264_level(templat.width, templat.height,
> +            &templat.max_references);
> +      } else {
> +         templat.max_references = 2;
> +      }
>   
>         context->decoder = drv->pipe->create_video_codec(drv->pipe, &templat);
>         if (!context->decoder) {
> diff --git a/src/gallium/state_trackers/va/picture.c b/src/gallium/state_trackers/va/picture.c
> index 5e7841a..9d4d1a8 100644
> --- a/src/gallium/state_trackers/va/picture.c
> +++ b/src/gallium/state_trackers/va/picture.c
> @@ -146,6 +146,7 @@ handlePictureParameterBuffer(vlVaDriver *drv, vlVaContext *context, vlVaBuffer *
>         /*bit_depth_luma_minus8*/
>         /*bit_depth_chroma_minus8*/
>         context->desc.h264.num_ref_frames = h264->num_ref_frames;
> +      context->decoder->max_references = MIN2(context->desc.h264.num_ref_frames, 16);
>         /*chroma_format_idc*/
>         /*residual_colour_transform_flag*/
>         /*gaps_in_frame_num_value_allowed_flag*/