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

[rshaffer at tunein.com]

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.

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.

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;
-- 
2.14.3 (Apple Git-98)