Re: [FFmpeg-devel] [PATCH v7 1/8] Add generic metadata injection using AV_PKT_DATA_METADATA_UPDATE

[Romain Beauxis <romain.beauxis@gmail.com>]

Le dim. 9 mars 2025 à 13:31, Michael Niedermayer
<michael@niedermayer.cc> a écrit :
>
> On Tue, Feb 25, 2025 at 04:01:14PM -0600, Romain Beauxis wrote:
> > libavcodec/decode.c: intercept `AV_PKT_DATA_METADATA_UPDATE` packet
> > extra data, attach them to the next decoded frame.
> >
> > ---
> >  libavcodec/decode.c | 20 ++++++++++++++++++++
> >  1 file changed, 20 insertions(+)
> >
> > diff --git a/libavcodec/decode.c b/libavcodec/decode.c
> > index cac7e620d2..96e2f0ce95 100644
> > --- a/libavcodec/decode.c
> > +++ b/libavcodec/decode.c
> > @@ -97,6 +97,8 @@ typedef struct DecodeContext {
> >      int lcevc_frame;
> >      int width;
> >      int height;
> > +
> > +    AVDictionary *pending_metadata;
> >  } DecodeContext;
> >
> >  static DecodeContext *decode_ctx(AVCodecInternal *avci)
> > @@ -729,6 +731,8 @@ int attribute_align_arg avcodec_send_packet(AVCodecContext *avctx, const AVPacke
> >  {
> >      AVCodecInternal *avci = avctx->internal;
> >      DecodeContext     *dc = decode_ctx(avci);
> > +    const uint8_t *side_metadata;
> > +    size_t size;
> >      int ret;
> >
> >      if (!avcodec_is_open(avctx) || !av_codec_is_decoder(avctx->codec))
> > @@ -746,6 +750,14 @@ int attribute_align_arg avcodec_send_packet(AVCodecContext *avctx, const AVPacke
> >          ret = av_packet_ref(avci->buffer_pkt, avpkt);
> >          if (ret < 0)
> >              return ret;
> > +
> > +        side_metadata = av_packet_get_side_data(avpkt, AV_PKT_DATA_METADATA_UPDATE, &size);
> > +        if (side_metadata) {
> > +            av_dict_free(&dc->pending_metadata);
> > +            ret = av_packet_unpack_dictionary(side_metadata, size, &dc->pending_metadata);
> > +            if (ret < 0)
> > +                return ret;
> > +        }
> >      } else
> >          dc->draining_started = 1;
> >
> > @@ -815,6 +827,7 @@ fail:
> >  int ff_decode_receive_frame(AVCodecContext *avctx, AVFrame *frame)
> >  {
> >      AVCodecInternal *avci = avctx->internal;
> > +    DecodeContext     *dc = decode_ctx(avci);
> >      int ret;
> >
> >      if (!avcodec_is_open(avctx) || !av_codec_is_decoder(avctx->codec))
> > @@ -887,6 +900,12 @@ int ff_decode_receive_frame(AVCodecContext *avctx, AVFrame *frame)
> >          }
> >      }
> >  #endif
> > +
> > +    if (dc->pending_metadata) {
> > +        av_dict_copy(&frame->metadata, dc->pending_metadata, AV_DICT_APPEND);
> > +        av_dict_free(&dc->pending_metadata);
> > +    }
> > +
> >      return 0;
> >  fail:
> >      av_frame_unref(frame);
>
> Does this work correctly, if theres a delay/latency in the decoder ?

Can you describe a scenario that you're thinking about?

> thx
>
> [...]
>
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
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