[FFmpeg-devel] [PATCH v2 2/2] avformat/flvenc: add option to read metadata from file
Gyan Doshi
ffmpeg at gyani.pro
Sat Feb 4 12:24:56 EET 2023
On 2023-02-04 03:46 pm, Paul B Mahol wrote:
> On 2/4/23, Gyan Doshi <ffmpeg at gyani.pro> wrote:
>>
>> On 2023-02-03 09:04 pm, Andreas Rheinhardt wrote:
>>> Gyan Doshi:
>>>> Useful, in conjuntion with option meta_period, to vary metadata during
>>>> stream.
>>>>
>>>> File format is ffmetadata.
>>>> ---
>>>> configure | 2 +-
>>>> doc/muxers.texi | 3 +
>>>> libavformat/flvenc.c | 133 +++++++++++++++++++++++++++++++++----------
>>>> 3 files changed, 107 insertions(+), 31 deletions(-)
>>>>
>>>> diff --git a/configure b/configure
>>>> index 9d78a244a3..de371632c4 100755
>>>> --- a/configure
>>>> +++ b/configure
>>>> @@ -3433,7 +3433,7 @@ eac3_demuxer_select="ac3_parser"
>>>> f4v_muxer_select="mov_muxer"
>>>> fifo_muxer_deps="threads"
>>>> flac_demuxer_select="flac_parser"
>>>> -flv_muxer_select="aac_adtstoasc_bsf"
>>>> +flv_muxer_select="aac_adtstoasc_bsf ffmetadata_demuxer"
>>>> gxf_muxer_select="pcm_rechunk_bsf"
>>>> hds_muxer_select="flv_muxer"
>>>> hls_demuxer_select="adts_header ac3_parser"
>>>> diff --git a/doc/muxers.texi b/doc/muxers.texi
>>>> index 02ecddf186..000c92b2a7 100644
>>>> --- a/doc/muxers.texi
>>>> +++ b/doc/muxers.texi
>>>> @@ -555,6 +555,9 @@ With every video packet.
>>>> @end table
>>>> Note that metadata will always be re-emitted if a metadata update event
>>>> is signalled.
>>>>
>>>> + at item meta_filename
>>>> +Specify a ffmetadata file from which to load metadata.
>>>> +
>>>> @end table
>>>>
>>>> @anchor{framecrc}
>>>> diff --git a/libavformat/flvenc.c b/libavformat/flvenc.c
>>>> index d1c7a493d1..1332b18b41 100644
>>>> --- a/libavformat/flvenc.c
>>>> +++ b/libavformat/flvenc.c
>>>> @@ -122,6 +122,10 @@ typedef struct FLVContext {
>>>> double framerate;
>>>> AVCodecParameters *data_par;
>>>>
>>>> + char *meta_filename;
>>>> + AVFormatContext *meta_ctx;
>>>> + AVDictionary *meta_dict;
>>>> +
>>>> int flags;
>>>> int meta_period;
>>>> } FLVContext;
>>>> @@ -277,6 +281,92 @@ static void put_amf_bool(AVIOContext *pb, int b)
>>>> avio_w8(pb, !!b);
>>>> }
>>>>
>>>> +static int read_metadata_from_file(AVFormatContext *s, unsigned int ts,
>>>> int header)
>>>> +{
>>>> + FLVContext *flv = s->priv_data;
>>>> + const AVInputFormat *meta_format = NULL;
>>>> + AVDictionary *current_meta_dict = NULL;
>>>> + float timestamp = ts/1000.f;
>>>> + int ret;
>>>> +
>>>> + if (!flv->meta_filename)
>>>> + return 0;
>>>> +
>>>> + meta_format = av_find_input_format("ffmetadata");
>>>> + if (!meta_format) {
>>>> + av_log(s, AV_LOG_ERROR, "ffmetadata demuxer not found.\n");
>>>> + return AVERROR(ENOSYS);
>>>> + }
>>>> +
>>>> + avformat_close_input(&flv->meta_ctx);
>>>> +
>>>> + ret = avformat_open_input(&flv->meta_ctx, flv->meta_filename,
>>>> meta_format, NULL);
>>>> + if (ret < 0) {
>>>> + av_log(s, AV_LOG_ERROR, "Failed to read metadata from file %s t:
>>>> %f.", flv->meta_filename, timestamp);
>>>> + if (flv->meta_dict)
>>>> + av_log(s, AV_LOG_ERROR, " Continuing with old metadata.");
>>>> + av_log(s, AV_LOG_ERROR, "\n");
>>>> + return ret;
>>>> + }
>>>> +
>>>> + if (flv->meta_dict) {
>>>> + av_dict_copy(¤t_meta_dict, flv->meta_dict, 0);
>>>> + av_dict_free(&flv->meta_dict);
>>>> + }
>>>> +
>>>> + ret = av_dict_copy(&flv->meta_dict, flv->meta_ctx->metadata, 0);
>>>> + if (ret < 0) {
>>>> + av_log(s, AV_LOG_ERROR, "Could not transfer metadata from %s at
>>>> %f seconds. Continuing with old metadata.\n", flv->meta_filename,
>>>> timestamp);
>>>> + av_dict_free(&flv->meta_dict);
>>>> + av_dict_copy(&flv->meta_dict, current_meta_dict, 0);
>>>> + av_dict_free(¤t_meta_dict);
>>>> + return ret;
>>>> + }
>>>> +
>>>> + av_log(s, AV_LOG_VERBOSE, "Metadata from file %s updated %s at %f
>>>> seconds.\n", flv->meta_filename, header ? "in header" : "in video
>>>> packet", timestamp);
>>>> + av_dict_free(¤t_meta_dict);
>>>> + avformat_close_input(&flv->meta_ctx);
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static int write_user_metadata_tag(AVFormatContext *s, AVDictionaryEntry
>>>> *tag, AVIOContext *pb, int *metadata_count)
>>>> +{
>>>> +
>>>> + av_log(s, AV_LOG_DEBUG, "Writing tag %s with value %s count: %d\n",
>>>> tag->key, tag->value, *metadata_count);
>>>> +
>>>> + if( !strcmp(tag->key, "width")
>>>> + ||!strcmp(tag->key, "height")
>>>> + ||!strcmp(tag->key, "videodatarate")
>>>> + ||!strcmp(tag->key, "framerate")
>>>> + ||!strcmp(tag->key, "videocodecid")
>>>> + ||!strcmp(tag->key, "audiodatarate")
>>>> + ||!strcmp(tag->key, "audiosamplerate")
>>>> + ||!strcmp(tag->key, "audiosamplesize")
>>>> + ||!strcmp(tag->key, "stereo")
>>>> + ||!strcmp(tag->key, "audiocodecid")
>>>> + ||!strcmp(tag->key, "duration")
>>>> + ||!strcmp(tag->key, "onMetaData")
>>>> + ||!strcmp(tag->key, "datasize")
>>>> + ||!strcmp(tag->key, "lasttimestamp")
>>>> + ||!strcmp(tag->key, "totalframes")
>>>> + ||!strcmp(tag->key, "hasAudio")
>>>> + ||!strcmp(tag->key, "hasVideo")
>>>> + ||!strcmp(tag->key, "hasCuePoints")
>>>> + ||!strcmp(tag->key, "hasMetadata")
>>>> + ||!strcmp(tag->key, "hasKeyframes")
>>>> + ){
>>>> + av_log(s, AV_LOG_DEBUG, "Ignoring metadata for %s\n",
>>>> tag->key);
>>>> + return AVERROR(EINVAL);
>>>> + }
>>>> + put_amf_string(pb, tag->key);
>>>> + avio_w8(pb, AMF_DATA_TYPE_STRING);
>>>> + put_amf_string(pb, tag->value);
>>>> + (*metadata_count)++;
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> static void write_metadata(AVFormatContext *s, unsigned int ts)
>>>> {
>>>> AVIOContext *pb = s->pb;
>>>> @@ -360,36 +450,11 @@ static void write_metadata(AVFormatContext *s,
>>>> unsigned int ts)
>>>> }
>>>>
>>>> ff_standardize_creation_time(s);
>>>> - while ((tag = av_dict_iterate(s->metadata, tag))) {
>>>> - if( !strcmp(tag->key, "width")
>>>> - ||!strcmp(tag->key, "height")
>>>> - ||!strcmp(tag->key, "videodatarate")
>>>> - ||!strcmp(tag->key, "framerate")
>>>> - ||!strcmp(tag->key, "videocodecid")
>>>> - ||!strcmp(tag->key, "audiodatarate")
>>>> - ||!strcmp(tag->key, "audiosamplerate")
>>>> - ||!strcmp(tag->key, "audiosamplesize")
>>>> - ||!strcmp(tag->key, "stereo")
>>>> - ||!strcmp(tag->key, "audiocodecid")
>>>> - ||!strcmp(tag->key, "duration")
>>>> - ||!strcmp(tag->key, "onMetaData")
>>>> - ||!strcmp(tag->key, "datasize")
>>>> - ||!strcmp(tag->key, "lasttimestamp")
>>>> - ||!strcmp(tag->key, "totalframes")
>>>> - ||!strcmp(tag->key, "hasAudio")
>>>> - ||!strcmp(tag->key, "hasVideo")
>>>> - ||!strcmp(tag->key, "hasCuePoints")
>>>> - ||!strcmp(tag->key, "hasMetadata")
>>>> - ||!strcmp(tag->key, "hasKeyframes")
>>>> - ){
>>>> - av_log(s, AV_LOG_DEBUG, "Ignoring metadata for %s\n",
>>>> tag->key);
>>>> - continue;
>>>> - }
>>>> - put_amf_string(pb, tag->key);
>>>> - avio_w8(pb, AMF_DATA_TYPE_STRING);
>>>> - put_amf_string(pb, tag->value);
>>>> - metadata_count++;
>>>> - }
>>>> +
>>>> + while (tag = av_dict_get(s->metadata, "", tag,
>>>> AV_DICT_IGNORE_SUFFIX))
>>>> + write_user_metadata_tag(s, tag, pb, &metadata_count);
>>>> + while (tag = av_dict_get(flv->meta_dict, "", tag,
>>>> AV_DICT_IGNORE_SUFFIX))
>>>> + write_user_metadata_tag(s, tag, pb, &metadata_count);
>>>>
>>>> if (write_duration_filesize) {
>>>> put_amf_string(pb, "filesize");
>>>> @@ -718,6 +783,7 @@ static int flv_write_header(AVFormatContext *s)
>>>> if (flv->flags & FLV_NO_METADATA) {
>>>> pb->seekable = 0;
>>>> } else {
>>>> + read_metadata_from_file(s, 0, 1);
>>>> write_metadata(s, 0);
>>>> }
>>>>
>>>> @@ -880,6 +946,7 @@ static int flv_write_packet(AVFormatContext *s,
>>>> AVPacket *pkt)
>>>> if (meta_upd_flag ||
>>>> (flv->meta_period == FLV_META_AT_KF && par->codec_type
>>>> == AVMEDIA_TYPE_VIDEO && (pkt->flags & AV_PKT_FLAG_KEY)) ||
>>>> (flv->meta_period == FLV_META_EVERY_PACKET && par->codec_type
>>>> == AVMEDIA_TYPE_VIDEO )) {
>>>> + read_metadata_from_file(s, ts, 0);
>>>> write_metadata(s, ts);
>>>> if (meta_upd_flag)
>>>> s->event_flags &= ~AVSTREAM_EVENT_FLAG_METADATA_UPDATED;
>>>> @@ -1053,6 +1120,11 @@ static void flv_deinit(AVFormatContext *s)
>>>> }
>>>> flv->filepositions = flv->head_filepositions = NULL;
>>>> flv->filepositions_count = 0;
>>>> +
>>>> + if (flv->meta_dict)
>>>> + av_dict_free(&flv->meta_dict);
>>>> +
>>>> + avformat_close_input(&flv->meta_ctx);
>>>> }
>>>>
>>>> static const AVOption options[] = {
>>>> @@ -1066,6 +1138,7 @@ static const AVOption options[] = {
>>>> { "at_start", "only once at start", 0,
>>>> AV_OPT_TYPE_CONST, {.i64 = FLV_META_ONCE_AT_START}, INT_MIN, INT_MAX,
>>>> AV_OPT_FLAG_ENCODING_PARAM, "meta_period" },
>>>> { "at_keyframes", "with every video keyframe", 0,
>>>> AV_OPT_TYPE_CONST, {.i64 = FLV_META_AT_KF}, INT_MIN, INT_MAX,
>>>> AV_OPT_FLAG_ENCODING_PARAM, "meta_period" },
>>>> { "every_packet", "with every video packet", 0,
>>>> AV_OPT_TYPE_CONST, {.i64 = FLV_META_EVERY_PACKET}, INT_MIN, INT_MAX,
>>>> AV_OPT_FLAG_ENCODING_PARAM, "meta_period" },
>>>> + { "meta_filename", "ffmetadata file to import metadata",
>>>> offsetof(FLVContext, meta_filename), AV_OPT_TYPE_STRING, {.str = NULL},
>>>> 0, 0, AV_OPT_FLAG_ENCODING_PARAM },
>>>> { NULL },
>>>> };
>>>>
>>> What does this achieve that can't be achieved by other means (namely by
>>> an API-user updating the relevant metadata dictionaries)?
>> This option together with meta_period is for CLI users. Similar to
>> drawtext's textfile + reload.
>> It's been used in production for over a year at a client. Think it will
>> be broadly useful.
> Not everything that is useful now is correct on long term.
>
> Muxer specific metadata handling by reading from files is big hack.
What would you suggest?
Regards,
Gyan
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