[FFmpeg-devel] [PATCH 1/2] libavformat/hls.c: support in-stream ID3 metadata update.

[Romain Beauxis <toots@rastageeks.org>]

This patch adds support for updating HLS metadata passed as ID3 frames.

This seems like a pretty straight-forward improvement. Updating the
metadaata of the first stream seems to be the mechanism is other places
in the code and works as expected.

---
 libavformat/hls.c | 54 ++++++++++++++++++++++++++++-------------------
 1 file changed, 32 insertions(+), 22 deletions(-)

diff --git a/libavformat/hls.c b/libavformat/hls.c
index f6b44c2e35..ba6634d57a 100644
--- a/libavformat/hls.c
+++ b/libavformat/hls.c
@@ -93,6 +93,12 @@ enum PlaylistType {
     PLS_TYPE_VOD
 };
 
+#define ID3_PRIV_OWNER_TS "com.apple.streaming.transportStreamTimestamp"
+#define ID3_PRIV_OWNER_AUDIO_SETUP "com.apple.streaming.audioDescription"
+
+#define ID3v2_PRIV_OWNER_TS ID3v2_PRIV_METADATA_PREFIX ID3_PRIV_OWNER_TS
+#define ID3v2_PRIV_OWNER_AUDIO_SETUP ID3v2_PRIV_METADATA_PREFIX ID3_PRIV_OWNER_AUDIO_SETUP
+
 /*
  * Each playlist has its own demuxer. If it currently is active,
  * it has an open AVIOContext too, and potentially an AVPacket
@@ -150,9 +156,7 @@ struct playlist {
     int64_t id3_offset; /* in stream original tb */
     uint8_t* id3_buf; /* temp buffer for id3 parsing */
     unsigned int id3_buf_size;
-    AVDictionary *id3_initial; /* data from first id3 tag */
-    int id3_found; /* ID3 tag found at some point */
-    int id3_changed; /* ID3 tag data has changed at some point */
+    AVDictionary *last_id3; /* data from the last id3 tag */
     ID3v2ExtraMeta *id3_deferred_extra; /* stored here until subdemuxer is opened */
 
     HLSAudioSetupInfo audio_setup_info;
@@ -270,7 +274,7 @@ static void free_playlist_list(HLSContext *c)
         av_freep(&pls->main_streams);
         av_freep(&pls->renditions);
         av_freep(&pls->id3_buf);
-        av_dict_free(&pls->id3_initial);
+        av_dict_free(&pls->last_id3);
         ff_id3v2_free_extra_meta(&pls->id3_deferred_extra);
         av_freep(&pls->init_sec_buf);
         av_packet_free(&pls->pkt);
@@ -1083,15 +1087,13 @@ static void parse_id3(AVFormatContext *s, AVIOContext *pb,
                       AVDictionary **metadata, int64_t *dts, HLSAudioSetupInfo *audio_setup_info,
                       ID3v2ExtraMetaAPIC **apic, ID3v2ExtraMeta **extra_meta)
 {
-    static const char id3_priv_owner_ts[] = "com.apple.streaming.transportStreamTimestamp";
-    static const char id3_priv_owner_audio_setup[] = "com.apple.streaming.audioDescription";
     ID3v2ExtraMeta *meta;
 
     ff_id3v2_read_dict(pb, metadata, ID3v2_DEFAULT_MAGIC, extra_meta);
     for (meta = *extra_meta; meta; meta = meta->next) {
         if (!strcmp(meta->tag, "PRIV")) {
             ID3v2ExtraMetaPRIV *priv = &meta->data.priv;
-            if (priv->datasize == 8 && !av_strncasecmp(priv->owner, id3_priv_owner_ts, 44)) {
+            if (priv->datasize == 8 && !av_strncasecmp(priv->owner, ID3_PRIV_OWNER_TS, strlen(ID3_PRIV_OWNER_TS))) {
                 /* 33-bit MPEG timestamp */
                 int64_t ts = AV_RB64(priv->data);
                 av_log(s, AV_LOG_DEBUG, "HLS ID3 audio timestamp %"PRId64"\n", ts);
@@ -1099,7 +1101,9 @@ static void parse_id3(AVFormatContext *s, AVIOContext *pb,
                     *dts = ts;
                 else
                     av_log(s, AV_LOG_ERROR, "Invalid HLS ID3 audio timestamp %"PRId64"\n", ts);
-            } else if (priv->datasize >= 8 && !av_strncasecmp(priv->owner, id3_priv_owner_audio_setup, 36)) {
+            } else if (priv->datasize >= 8 &&
+                       !av_strncasecmp(priv->owner, ID3_PRIV_OWNER_AUDIO_SETUP, 36) &&
+                       audio_setup_info) {
                 ff_hls_senc_read_audio_setup_info(audio_setup_info, priv->data, priv->datasize);
             }
         } else if (!strcmp(meta->tag, "APIC") && apic)
@@ -1113,9 +1117,10 @@ static int id3_has_changed_values(struct playlist *pls, AVDictionary *metadata,
 {
     const AVDictionaryEntry *entry = NULL;
     const AVDictionaryEntry *oldentry;
+
     /* check that no keys have changed values */
     while ((entry = av_dict_iterate(metadata, entry))) {
-        oldentry = av_dict_get(pls->id3_initial, entry->key, NULL, AV_DICT_MATCH_CASE);
+        oldentry = av_dict_get(pls->last_id3, entry->key, NULL, AV_DICT_MATCH_CASE);
         if (!oldentry || strcmp(oldentry->value, entry->value) != 0)
             return 1;
     }
@@ -1143,35 +1148,40 @@ static void handle_id3(AVIOContext *pb, struct playlist *pls)
     ID3v2ExtraMetaAPIC *apic = NULL;
     ID3v2ExtraMeta *extra_meta = NULL;
     int64_t timestamp = AV_NOPTS_VALUE;
+    // Only set audio_setup_info on first id3 chunk.
+    HLSAudioSetupInfo *audio_setup_info = pls->last_id3 ? NULL : &pls->audio_setup_info;
 
-    parse_id3(pls->ctx, pb, &metadata, &timestamp, &pls->audio_setup_info, &apic, &extra_meta);
+    parse_id3(pls->ctx, pb, &metadata, &timestamp, audio_setup_info, &apic, &extra_meta);
 
-    if (timestamp != AV_NOPTS_VALUE) {
+    if (pls->id3_mpegts_timestamp == AV_NOPTS_VALUE && timestamp != AV_NOPTS_VALUE) {
         pls->id3_mpegts_timestamp = timestamp;
         pls->id3_offset = 0;
     }
 
-    if (!pls->id3_found) {
-        /* initial ID3 tags */
-        av_assert0(!pls->id3_deferred_extra);
-        pls->id3_found = 1;
-
+    if (id3_has_changed_values(pls, metadata, apic)) {
         /* get picture attachment and set text metadata */
         if (pls->ctx->nb_streams)
             ff_id3v2_parse_apic(pls->ctx, extra_meta);
-        else
+        else {
+            av_assert0(!pls->id3_deferred_extra);
             /* demuxer not yet opened, defer picture attachment */
             pls->id3_deferred_extra = extra_meta;
+        }
 
         ff_id3v2_parse_priv_dict(&metadata, extra_meta);
+
+        av_dict_set(&metadata, ID3v2_PRIV_OWNER_TS, NULL, 0);
+        av_dict_set(&metadata, ID3v2_PRIV_OWNER_AUDIO_SETUP, NULL, 0);
+
+        av_dict_free(&pls->ctx->metadata);
         av_dict_copy(&pls->ctx->metadata, metadata, 0);
-        pls->id3_initial = metadata;
 
+        if (pls->n_main_streams)
+            av_dict_copy(&pls->main_streams[0]->metadata, metadata, 0);
+
+        if (pls->last_id3) av_dict_free(&pls->last_id3);
+        pls->last_id3 = metadata;
     } else {
-        if (!pls->id3_changed && id3_has_changed_values(pls, metadata, apic)) {
-            avpriv_report_missing_feature(pls->parent, "Changing ID3 metadata in HLS audio elementary stream");
-            pls->id3_changed = 1;
-        }
         av_dict_free(&metadata);
     }
 
-- 
2.39.3 (Apple Git-145)

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