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

[Liu Steven <lq@chinaffmpeg.org>]

> On Mar 29, 2024, at 06:51, Romain Beauxis <toots@rastageeks.org> wrote:
> 
> On Mon, Mar 25, 2024, 19:58 Romain Beauxis <toots@rastageeks.org> wrote:
> 
>> 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.
>> 
> 
> 
> Hello!
> 
> Any interest in reviewing this?

Patchset looks good to me, looks better than before patch.
> 
> 
> ---
>> 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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