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

[Andreas Rheinhardt]

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, \
> 

Is there anyone who asked for this feature?

- Andreas