[FFmpeg-devel] [PATCH 1/3] avcodec/av1_metadata: filter parameter sets in packet side data

[Andreas Rheinhardt]

James Almer:
> Extradata included in packet side data is meant to replace the codec context
> extradata. So when muxing for example to MP4 without this change and if
> extradata is present in a packet side data, the result will be that the
> parameter sets present in keyframes will be filtered, but the parameter sets
> ultimately included in the av1C box will not.
> 
> This is especially important for AV1 as both currently supported encoders don't
> export the Sequence Header in the codec context extradata, but as packet side
> data instead.
> 
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
>  libavcodec/av1_metadata_bsf.c | 52 +++++++++++++++++++++++++++++++++++
>  1 file changed, 52 insertions(+)
> 
> diff --git a/libavcodec/av1_metadata_bsf.c b/libavcodec/av1_metadata_bsf.c
> index dd0c9b6148..f3161cb286 100644
> --- a/libavcodec/av1_metadata_bsf.c
> +++ b/libavcodec/av1_metadata_bsf.c
> @@ -111,6 +111,54 @@ static int av1_metadata_update_sequence_header(AVBSFContext *bsf,
>      return 0;
>  }
>  
> +static int av1_metadata_update_side_data(AVBSFContext *bsf, AVPacket *pkt)
> +{
> +    AV1MetadataContext *ctx = bsf->priv_data;
> +    CodedBitstreamFragment *frag = &ctx->access_unit;
> +    AV1RawOBU *obu;
> +    uint8_t *side_data;
> +    int side_data_size;
> +    int err, i;
> +
> +    side_data = av_packet_get_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA,
> +                                        &side_data_size);
> +    if (!side_data_size)
> +        return 0;
> +
> +    err = ff_cbs_read(ctx->cbc, frag, side_data, side_data_size);
> +    if (err < 0) {
> +        av_log(bsf, AV_LOG_ERROR, "Failed to read extradata from packet side data.\n");
> +        goto fail;

You can actually return immediately in this whole function: The fragment
will be reset in the fail part of av1_metadata_filter().

> +    }
> +
> +    for (i = 0; i < frag->nb_units; i++) {
> +        if (frag->units[i].type == AV1_OBU_SEQUENCE_HEADER) {
> +            obu = frag->units[i].content;
> +            err = av1_metadata_update_sequence_header(bsf, &obu->obu.sequence_header);
> +            if (err < 0)
> +                goto fail;
> +        }
> +    }
> +
> +    err = ff_cbs_write_fragment_data(ctx->cbc, frag);
> +    if (err < 0) {
> +        av_log(bsf, AV_LOG_ERROR, "Failed to write extradata into packet side data.\n");
> +        goto fail;
> +    }
> +
> +    side_data = av_packet_new_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA, frag->data_size);
> +    if (!side_data) {
> +        err = AVERROR(ENOMEM);
> +        goto fail;
> +    }
> +    memcpy(side_data, frag->data, frag->data_size);
> +
> +    err = 0;
> +fail:
> +    ff_cbs_fragment_reset(ctx->cbc, frag);
> +    return err;
> +}
> +
>  static int av1_metadata_filter(AVBSFContext *bsf, AVPacket *pkt)
>  {
>      AV1MetadataContext *ctx = bsf->priv_data;
> @@ -122,6 +170,10 @@ static int av1_metadata_filter(AVBSFContext *bsf, AVPacket *pkt)
>      if (err < 0)
>          return err;
>  
> +    err = av1_metadata_update_side_data(bsf, pkt);
> +    if (err < 0)
> +        goto fail;
> +
>      err = ff_cbs_read_packet(ctx->cbc, frag, pkt);
>      if (err < 0) {
>          av_log(bsf, AV_LOG_ERROR, "Failed to read packet.\n");
>