[FFmpeg-devel] [PATCH] avformat: add AVFormatContext.first_pts_wallclock

[Gyan Doshi]

On 2022-06-16 02:39 pm, Gyan Doshi wrote:
> Stores wallclock time for the first packet received with a pts.

Comments?
> ---
>   doc/APIchanges         |  3 +++
>   libavformat/avformat.h | 10 ++++++++++
>   libavformat/demux.c    |  3 +++
>   libavformat/options.c  |  1 +
>   libavformat/version.h  |  2 +-
>   5 files changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/doc/APIchanges b/doc/APIchanges
> index 5857e67ae6..3d472b8963 100644
> --- a/doc/APIchanges
> +++ b/doc/APIchanges
> @@ -14,6 +14,9 @@ libavutil:     2021-04-27
>   
>   API changes, most recent first:
>   
> +2022-06-xx - xxxxxxxxxx - lavf 59.26.100 - avformat.h
> +  Add and set AVFormatContext.first_pts_wallclock field.
> +
>   2022-06-12 - xxxxxxxxxx - lavf 59.25.100 - avio.h
>     Add avio_vprintf(), similar to avio_printf() but allow to use it
>     from within a function taking a variable argument list as input.
> diff --git a/libavformat/avformat.h b/libavformat/avformat.h
> index f12fa7d904..56f9656a68 100644
> --- a/libavformat/avformat.h
> +++ b/libavformat/avformat.h
> @@ -1808,6 +1808,16 @@ typedef struct AVFormatContext {
>        */
>       int max_probe_packets;
>   
> +    /**
> +     * Wallclock start time of the stream in real world time, in microseconds
> +     * since the Unix epoch (00:00 1st January 1970). That is, the first packet
> +     * with a set pts was received at this real world time.
> +     * - demuxing: Set by libavformat. Users may want to use start_time_realtime
> +     *             if set.
> +     * - muxing: unused.
> +     */
> +    int64_t first_pts_wallclock;
> +
>       /**
>        * A callback for closing the streams opened with AVFormatContext.io_open().
>        *
> diff --git a/libavformat/demux.c b/libavformat/demux.c
> index 1620716716..9335a6efcd 100644
> --- a/libavformat/demux.c
> +++ b/libavformat/demux.c
> @@ -628,6 +628,9 @@ FF_ENABLE_DEPRECATION_WARNINGS
>   
>           force_codec_ids(s, st);
>   
> +        if (s->first_pts_wallclock == AV_NOPTS_VALUE && pkt->pts != AV_NOPTS_VALUE)
> +            s->first_pts_wallclock = av_gettime();
> +
>           /* TODO: audio: time filter; video: frame reordering (pts != dts) */
>           if (s->use_wallclock_as_timestamps)
>               pkt->dts = pkt->pts = av_rescale_q(av_gettime(), AV_TIME_BASE_Q, st->time_base);
> diff --git a/libavformat/options.c b/libavformat/options.c
> index 0079a06d9a..4cc168939f 100644
> --- a/libavformat/options.c
> +++ b/libavformat/options.c
> @@ -184,6 +184,7 @@ AVFormatContext *avformat_alloc_context(void)
>           return NULL;
>       }
>   
> +    s->first_pts_wallclock = AV_NOPTS_VALUE;
>       si->shortest_end = AV_NOPTS_VALUE;
>   
>       return s;
> diff --git a/libavformat/version.h b/libavformat/version.h
> index 966ebb7ed3..0708d619c0 100644
> --- a/libavformat/version.h
> +++ b/libavformat/version.h
> @@ -31,7 +31,7 @@
>   
>   #include "version_major.h"
>   
> -#define LIBAVFORMAT_VERSION_MINOR  25
> +#define LIBAVFORMAT_VERSION_MINOR  26
>   #define LIBAVFORMAT_VERSION_MICRO 100
>   
>   #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \