[FFmpeg-devel] [PATCH] libavformat/hls: Support metadata updates from subdemuxers

[wm4]

On Fri,  2 Feb 2018 12:59:45 -0800
rshaffer at tunein.com wrote:

> From: Richard Shaffer <rshaffer at tunein.com>
> 
> If a subdemuxer has the updated metadata event flag set, the metadata is copied
> to the corresponding stream. The flag is cleared on the subdemuxer and the
> appropriate event flag is set on the stream.
> ---
> This is iteration #2.

You can pass "-v2" as argument to git send-email to automatically add
"v2" to the subject.

> 
> In this version, we don't try to copy metadata from subdemuxer streams, only
> from the AVFormatContext. The case where metadata is updated on a sub-demuxer
> stream would have probably never happened.

Oh, I thought it was the other way around.

> The above change made the code that was previously in the
> update_metadata_from_subdemuxer function a little simpler. That function was
> also kind of ugly, because in one case it read and set flags, and in another it
> didn't. It seemed simpler just to move the respective updates into read_header
> and read_packet, respectively, so that's what I did.
> 
> -Richard
> 
>  libavformat/hls.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/libavformat/hls.c b/libavformat/hls.c
> index 9bd54c84cc..c578bf86e3 100644
> --- a/libavformat/hls.c
> +++ b/libavformat/hls.c
> @@ -1062,6 +1062,7 @@ static void handle_id3(AVIOContext *pb, struct playlist *pls)
>              /* demuxer not yet opened, defer picture attachment */
>              pls->id3_deferred_extra = extra_meta;
>  
> +        ff_id3v2_parse_priv_dict(&metadata, &extra_meta);
>          av_dict_copy(&pls->ctx->metadata, metadata, 0);
>          pls->id3_initial = metadata;
>  
> @@ -1960,6 +1961,7 @@ static int hls_read_header(AVFormatContext *s)
>          if (pls->id3_deferred_extra && pls->ctx->nb_streams == 1) {
>              ff_id3v2_parse_apic(pls->ctx, &pls->id3_deferred_extra);
>              avformat_queue_attached_pictures(pls->ctx);
> +            ff_id3v2_parse_priv(pls->ctx, &pls->id3_deferred_extra);
>              ff_id3v2_free_extra_meta(&pls->id3_deferred_extra);
>              pls->id3_deferred_extra = NULL;
>          }
> @@ -1986,6 +1988,13 @@ static int hls_read_header(AVFormatContext *s)
>          if (ret < 0)
>              goto fail;
>  
> +        /*
> +         * Copy any metadata from playlist to main streams, but do not set
> +         * event flags.
> +         */
> +        if (pls->n_main_streams)
> +            av_dict_copy(&pls->main_streams[0]->metadata, pls->ctx->metadata, 0);
> +
>          add_metadata_from_renditions(s, pls, AVMEDIA_TYPE_AUDIO);
>          add_metadata_from_renditions(s, pls, AVMEDIA_TYPE_VIDEO);
>          add_metadata_from_renditions(s, pls, AVMEDIA_TYPE_SUBTITLE);
> @@ -2170,6 +2179,17 @@ static int hls_read_packet(AVFormatContext *s, AVPacket *pkt)
>              return ret;
>          }
>  
> +        // If sub-demuxer reports updated metadata, copy it to the first stream
> +        // and set its AVSTREAM_EVENT_FLAG_METADATA_UPDATED flag.
> +        if (pls->ctx->event_flags & AVFMT_EVENT_FLAG_METADATA_UPDATED) {
> +            if (pls->n_main_streams) {
> +                st = pls->main_streams[0];
> +                av_dict_copy(&st->metadata, pls->ctx->metadata, 0);
> +                st->event_flags |= AVSTREAM_EVENT_FLAG_METADATA_UPDATED;
> +            }
> +            pls->ctx->event_flags &= ~AVFMT_EVENT_FLAG_METADATA_UPDATED;
> +        }
> +
>          /* check if noheader flag has been cleared by the subdemuxer */
>          if (pls->has_noheader_flag && !(pls->ctx->ctx_flags & AVFMTCTX_NOHEADER)) {
>              pls->has_noheader_flag = 0;

Fine then. If it works ad nobody else has comments, I can push on Monday
or so.