[FFmpeg-devel] [PATCH v2 2/2] avformat/flvenc: add option to read metadata from file
Paul B Mahol
onemda at gmail.com
Sat Feb 4 12:16:22 EET 2023
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.
NAK.
>
> Regards,
> Gyan
>
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