Re: [FFmpeg-devel] [PATCH] avfilter/src_movie: activate & dr

[Paul B Mahol <onemda@gmail.com>]

On Thu, May 18, 2023 at 8:01 PM James Almer <jamrial@gmail.com> wrote:

> On 5/18/2023 2:44 PM, Paul B Mahol wrote:
> > On Thu, May 18, 2023 at 7:31 PM James Almer <jamrial@gmail.com> wrote:
> >
> >> On 5/18/2023 7:22 AM, Paul B Mahol wrote:
> >>>  From af73b69a0be9033fddf222b6e9ac60799de85691 Mon Sep 17 00:00:00 2001
> >>> From: Paul B Mahol <onemda@gmail.com>
> >>> Date: Mon, 15 May 2023 21:54:25 +0200
> >>> Subject: [PATCH 26/27] avfilter/src_movie: dr support
> >>>
> >>> Signed-off-by: Paul B Mahol <onemda@gmail.com>
> >>> ---
> >>>   libavfilter/src_movie.c | 44
> +++++++++++++++++++++++++++++++++++++++--
> >>>   1 file changed, 42 insertions(+), 2 deletions(-)
> >>>
> >>> diff --git a/libavfilter/src_movie.c b/libavfilter/src_movie.c
> >>> index 5937613d13..a2ecc5a625 100644
> >>> --- a/libavfilter/src_movie.c
> >>> +++ b/libavfilter/src_movie.c
> >>> @@ -23,7 +23,6 @@
> >>>    * @file
> >>>    * movie video source
> >>>    *
> >>> - * @todo use direct rendering (no allocation of a new frame)
> >>>    * @todo support a PTS correction mechanism
> >>>    */
> >>>
> >>> @@ -156,6 +155,43 @@ static AVStream *find_stream(void *log,
> >> AVFormatContext *avf, const char *spec)
> >>>       return found;
> >>>   }
> >>>
> >>> +static int get_buffer(AVCodecContext *avctx, AVFrame *frame, int
> flags)
> >>> +{
> >>> +    int linesize_align[AV_NUM_DATA_POINTERS];
> >>> +    AVFilterLink *outlink = frame->opaque;
> >>> +    int w, h, ow, oh;
> >>> +    AVFrame *new;
> >>> +
> >>> +    h = oh = frame->height;
> >>> +    w = ow = frame->width;
> >>> +
> >>> +    if (!(avctx->codec->capabilities & AV_CODEC_CAP_DR1))
> >>> +        return avcodec_default_get_buffer2(avctx, frame, flags);
> >>> +
> >>> +    switch (avctx->codec_type) {
> >>> +    case AVMEDIA_TYPE_VIDEO:
> >>> +        avcodec_align_dimensions2(avctx, &w, &h, linesize_align);
> >>> +        new = ff_default_get_video_buffer(outlink, w, h);
> >>> +        break;
> >>> +    case AVMEDIA_TYPE_AUDIO:
> >>> +        new = ff_default_get_audio_buffer(outlink, frame->nb_samples);
> >>
> >> I wonder, are these two functions thread safe?
> >> AVCodecContext.get_buffer2() no longer supports non-thread safe
> >> callbacks, and these seem to allocate and replace the pool inside
> >> outlink as required. If called from more than one thread with different
> >> frame parameters, wouldn't there be a race?
> >>
> >
> > I encountered no issues in my testing.
>
> Try a sample that changes dimensions every other frame, like
> vp9-test-vectors/vp90-2-05-resize.ivf, and make sure to set filter
> threads so it's propagated to the src_movie internal decoder, to some
> value like 4 or higher. Run it under tsan.
>
>
I tried that, and also own .h264 file hash decoding is always same.
tsan shows warnings for both without and with this filter and frame
threading.


> >
> >
> >>
> >>> +        break;
> >>> +    default:
> >>> +        return -1;
> >>> +    }
> >>> +
> >>> +    av_frame_copy_props(new, frame);
> >>> +    av_frame_unref(frame);
> >>> +    av_frame_move_ref(frame, new);
> >>> +    av_frame_free(&new);
> >>> +
> >>> +    frame->opaque = outlink;
> >>> +    frame->width  = ow;
> >>> +    frame->height = oh;
> >>> +
> >>> +    return 0;
> >>> +}
> >>> +
> >>>   static int open_stream(AVFilterContext *ctx, MovieStream *st, int
> >> dec_threads)
> >>>   {
> >>>       const AVCodec *codec;
> >>> @@ -171,6 +207,8 @@ static int open_stream(AVFilterContext *ctx,
> >> MovieStream *st, int dec_threads)
> >>>       if (!st->codec_ctx)
> >>>           return AVERROR(ENOMEM);
> >>>
> >>> +    st->codec_ctx->flags |= AV_CODEC_FLAG_COPY_OPAQUE;
> >>> +    st->codec_ctx->get_buffer2 = get_buffer;
> >>>       ret = avcodec_parameters_to_context(st->codec_ctx,
> >> st->st->codecpar);
> >>>       if (ret < 0)
> >>>           return ret;
> >>> @@ -479,8 +517,10 @@ static int movie_decode_packet(AVFilterContext
> *ctx)
> >>>       /* send the packet to its decoder, if any */
> >>>       pkt_out_id = pkt.stream_index > movie->max_stream_index ? -1 :
> >>>                    movie->out_index[pkt.stream_index];
> >>> -    if (pkt_out_id >= 0)
> >>> +    if (pkt_out_id >= 0) {
> >>> +        pkt.opaque = ctx->outputs[pkt_out_id];
> >>>           ret = avcodec_send_packet(movie->st[pkt_out_id].codec_ctx,
> >> &pkt);
> >>> +    }
> >>>       av_packet_unref(&pkt);
> >>>
> >>>       return ret;
> >>> --
> >>> 2.39.1
> >>>
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> >>
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