[FFmpeg-devel] [PATCH 4/4] concatdec: add support for injecting packet metadata

[Nicolas George]

L'octidi 18 messidor, an CCXXIII, Marton Balint a écrit :
> Signed-off-by: Marton Balint <cus at passwd.hu>
> ---
>  doc/demuxers.texi       |  4 ++++
>  libavformat/concatdec.c | 30 ++++++++++++++++++++++++++++++
>  2 files changed, 34 insertions(+)
> 
> diff --git a/doc/demuxers.texi b/doc/demuxers.texi
> index 4ba797e..28244f3 100644
> --- a/doc/demuxers.texi
> +++ b/doc/demuxers.texi
> @@ -142,6 +142,10 @@ before the specified Out point.
>  The duration of the files (if not specified by the @code{duration}
>  directive) will be reduced based on their specified Out point.
>  
> + at item @code{metadata @var{string}}
> +Metadata of the file. The specified metadata (which consists of
> + at code{key=value} pairs seperated by commas) will be set for each file packet.

This looks like a step into escaping hell.

	metadata foo=bar,baz=qux

	metadata foo=bar
	metadata baz=qux

Would the second form be ok for you?

> +
>  @item @code{stream}
>  Introduce a stream in the virtual file.
>  All subsequent stream-related directives apply to the last introduced
> diff --git a/libavformat/concatdec.c b/libavformat/concatdec.c
> index eaf34b0..66e81c8 100644
> --- a/libavformat/concatdec.c
> +++ b/libavformat/concatdec.c
> @@ -45,6 +45,8 @@ typedef struct {
>      ConcatStream *streams;
>      int64_t inpoint;
>      int64_t outpoint;
> +    char *metadata;
> +    int metadata_len;
>      int nb_streams;
>  } ConcatFile;
>  
> @@ -329,6 +331,7 @@ static int concat_read_close(AVFormatContext *avf)
>          avformat_close_input(&cat->avf);
>      for (i = 0; i < cat->nb_files; i++) {
>          av_freep(&cat->files[i].url);
> +        av_freep(&cat->files[i].metadata);
>          av_freep(&cat->files[i].streams);
>      }
>      av_freep(&cat->files);
> @@ -381,6 +384,27 @@ static int concat_read_header(AVFormatContext *avf)
>                  file->inpoint = dur;
>              else if (!strcmp(keyword, "out"))
>                  file->outpoint = dur;
> +        } else if (!strcmp(keyword, "metadata")) {
> +            AVDictionary *opts = NULL;
> +            char *metadata;
> +            if (file->metadata) {
> +                av_log(avf, AV_LOG_ERROR, "Line %d: metadata is already provided\n", line);
> +                FAIL(AVERROR_INVALIDDATA);
> +            }
> +            metadata = av_get_token((const char **)&cursor, SPACE_CHARS);
> +            if (!metadata) {
> +                av_log(avf, AV_LOG_ERROR, "Line %d: metadata required\n", line);
> +                FAIL(AVERROR_INVALIDDATA);
> +            }
> +            if ((ret = av_dict_parse_string(&opts, metadata, "=", ",", 0)) < 0) {
> +                av_log(avf, AV_LOG_ERROR, "Line %d: failed to parse metadata string\n", line);
> +                av_freep(&metadata);
> +                av_dict_free(&opts);
> +                FAIL(AVERROR_INVALIDDATA);
> +            }
> +            file->metadata = av_packet_pack_dictionary(opts, &file->metadata_len);
> +            av_freep(&metadata);
> +            av_dict_free(&opts);
>          } else if (!strcmp(keyword, "stream")) {
>              if (!avformat_new_stream(avf, NULL))
>                  FAIL(AVERROR(ENOMEM));
> @@ -576,6 +600,12 @@ static int concat_read_packet(AVFormatContext *avf, AVPacket *pkt)
>      av_log(avf, AV_LOG_DEBUG, " -> pts:%s pts_time:%s dts:%s dts_time:%s\n",
>             av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, &st->time_base),
>             av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, &st->time_base));
> +    if (cat->cur_file->metadata) {
> +        uint8_t* metadata;
> +        if (!(metadata = av_packet_new_side_data(pkt, AV_PKT_DATA_STRINGS_METADATA, cat->cur_file->metadata_len)))
> +            return AVERROR(ENOMEM);
> +        memcpy(metadata, cat->cur_file->metadata, cat->cur_file->metadata_len);
> +    }
>      return ret;
>  }
>  

No other objection, but can you explain the use case? Packet metadata is not
very common.

Regards,

-- 
  Nicolas George
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