On Tue,  5 Aug 2014 12:58:47 -0400, Andrew Stone <[email protected]> wrote:
> The only flags, for now, indicate if metadata was updated and are set after 
> each call to
> av_read_frame(). This comes with the caveat that, on stream start, it might 
> not be set properly
> as packets might be buffered in AVFormatContext.packet_buffer before being 
> given to the user
> in av_read_frame().
> ---
>  doc/APIchanges         |  4 ++++
>  libavformat/avformat.h | 14 ++++++++++++++
>  libavformat/version.h  |  2 +-
>  3 files changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/doc/APIchanges b/doc/APIchanges
> index 261993b..a677e42 100644
> --- a/doc/APIchanges
> +++ b/doc/APIchanges
> @@ -13,6 +13,10 @@ libavutil:     2013-12-xx
>  
>  API changes, most recent first:
>  
> +2014-xx-xx - xxxxxxx - lavf 55.21.0 - avformat.h
> +  Add AVFormatContext.event_flags for signaling to the user when events
> +  have happened in the stream.
> +
>  2014-07-xx - xxxxxxx - lavu 53.19.0 - avstring.h
>    Make name matching function from lavf public as av_match_name().
>  
> diff --git a/libavformat/avformat.h b/libavformat/avformat.h
> index ab2081a..6b25d6a 100644
> --- a/libavformat/avformat.h
> +++ b/libavformat/avformat.h
> @@ -296,6 +296,10 @@ struct AVFormatContext;
>   *    -  sorting  -- a modified version of a tag that should be used for
>   *       sorting will have '-sort' appended. E.g. artist="The Beatles",
>   *       artist-sort="Beatles, The".
> + * - Some protocols and demuxers support metadata updates. After a successful
> + *   call to av_read_packet(), AVFormatContext.event_flags will be updated to
> + *   indicate if metadata was updated. Currently, only file (AVFormatContext)
> + *   and stream (AVStream) metadata change.
>   *
>   * -  Demuxers attempt to export metadata in a generic format, however tags
>   *    with no generic equivalents are left as they are stored in the 
> container.
> @@ -1177,6 +1181,16 @@ typedef struct AVFormatContext {
>       * @see AVCodecContext.strict_std_compliance
>       */
>      int strict_std_compliance;
> +
> +    /**
> +     * Flags for the user to detect events happening on the stream. Flags 
> must
> +     * be cleared by the user once the event has been handled.
> +     * A combination of AVFMT_EVENT_FLAG_*.
> +     */
> +    int event_flags;
> +#define AVFMT_EVENT_FLAG_METADATA_UPDATED        0x0001 ///< The call 
> resulted in updated metadata for the whole file.
> +#define AVFMT_EVENT_FLAG_STREAM_METADATA_UPDATED 0x0002 ///< The call 
> resulted in updated metadata for a stream.

My original suggestion in the last thread was to have a separate set of flags
for each stream (+global). That way you can see which stream exactly got
updated.
Or is there some specific reason to put all the flags here?

-- 
Anton Khirnov
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