[FFmpeg-devel] [PATCH] avfilter/setparams: add FF_FILTER_FLAG_HWFRAME_AWARE

[Pavel Koshevoy]

On Tue, Sep 29, 2020 at 12:14 PM Mark Thompson <sw at jkqxz.net> wrote:

> On 29/09/2020 18:14, Pavel Koshevoy wrote:
> > On Tue, Sep 29, 2020 at 10:09 AM Mark Thompson <sw at jkqxz.net> wrote:
> >
>
> <snip>
>
> >> - Mark
> >>
> >>
> > It's pretty much this use case, except I'm not using ffmpeg cli but the
> > avfilter api to configure the filter chain, and I'm working with
> > AV_PIX_FMT_CUDA frames.
> > Perhaps I am mis-using the api, but my patch was sufficient for my needs:
> >
> > ```
> >      bool
> >      VideoFilterChain::setup_filter_links(int num_threads)
> >      {
> >          graph_ = avfilter_graph_alloc();
> >          graph_->nb_threads = num_threads;
> >          int err = avfilter_graph_parse2(graph_, filters_.c_str(), &in_,
> > &out_);
> >          UL_FAIL_IF_AVERROR(err);
> >
> >          if (hw_frames_.ref_)
> >          {
> >              AVHWFramesContext * hw_frames_ctx =
> > hw_frames_.get<AVHWFramesContext>();
> >              AVBufferRef * device_ref = hw_frames_ctx->device_ref;
> >
> >              for (int i = 0; i < graph_->nb_filters; i++)
> >              {
> >                  AVFilterContext * filter_ctx = graph_->filters[i];
> >                  UL_ASSERT(!filter_ctx->hw_device_ctx);
> >                  filter_ctx->hw_device_ctx = av_buffer_ref(device_ref);
> >
> >                  bool found_hwdownload = strcmp(filter_ctx->filter->name,
> > "hwdownload") == 0;
> >                  if (found_hwdownload)
> >                  {
> >                      break;
> >                  }
> >
> >                  for (int j = 0; j < filter_ctx->nb_outputs; j++)
> >                  {
> >                      AVFilterLink * link = filter_ctx->outputs[j];
> >                      UL_ASSERT(!link->hw_frames_ctx);
> >                      link->hw_frames_ctx =
> av_buffer_ref(hw_frames_.ref_);
>
>
> <
> http://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavfilter/avfilter.h;h=99297ae798aa325ac37836a3a90d9a3f8e1e7a95;hb=HEAD#l497
> >
>
> Don't write to internal fields.
>
> I'm not sure exactly what you're trying to do by writing the internal
> context fields in this section, but I suspect that if you just remove it
> entirely then the expected context propagation will happen and it will work.
>
>
Okay, if I fix my API mis-use and context propagation happens
automagically  (idk where it would get the context in the 1st place,
yet)... won't that still leave me with setparams that is not
FF_FILTER_FLAG_HWFRAME_AWARE and avfilter_config_links would still fail?

Thank you,
    Pavel.