[FFmpeg-devel] [PATCH] Add hwaccel_data infrastructure

[Gwenole Beauchesne]

On Wed, 4 Mar 2009, Michael Niedermayer wrote:

>> Because I suggested open/close and you said only when needed. :) So I
>> assumed it was the wrong route since, currently, VA API only needs
>> av_mallocz() at frame buffer creation and do extra work at frame
>> buffer destruction.
>
> can you explain what this extra work is?

For VA API:

int ff_vaapi_destroy_picture(AVCodecContext *avctx, AVFrame *pic)
{
     struct vaapi_render_state_private *rds = pic->hwaccel_data_private;
     assert(rds);
     if (rds->slice_data) {
         if (!rds->mapped_slice_data)
             av_free(rds->slice_data);
         rds->slice_data = NULL;
     }
     if (rds->slice_params) {
         if (!rds->mapped_slice_data)
             av_free(rds->slice_params);
         rds->slice_params = NULL;
     }
     av_free(rds);
     return 0;
}

I could do that at ::end_frame() time, once they are committed, though.

However, for VDPAU, I am not sure there is another place than a ::close() 
to destroy the bitstreamBuffers, unless they are copied locally in 
vdp_decoder_render(). IIRC, this is asynchronous so if we delete them 
straight away, some weird things could happen when the function comes to 
actually need them later. ;-)