On date Monday 2016-01-18 21:56:30 +0100, Marton Balint encoded:
> This option can force the segmenter to only start a new segment if a packet
> reaches the muxer whithin the specified duration after the segmenting clock
> time, which makes it more resilient to backward local time jumps, such as leap
> seconds or transition to standard time from daylight savings time.
>
> Signed-off-by: Marton Balint <c...@passwd.hu>
> ---
> doc/muxers.texi | 13 +++++++++++++
> libavformat/segment.c | 4 +++-
> 2 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/doc/muxers.texi b/doc/muxers.texi
> index c304221..2ed468e 100644
> --- a/doc/muxers.texi
> +++ b/doc/muxers.texi
> @@ -1110,6 +1110,19 @@ create files at 12:05, 12:20, 12:35, etc.
>
> Default value is "0".
>
> +@item segment_clocktime_wrap_duration @var{duration}
> +By setting this option you can force the segmenter to only start a new
> segment
> +if a packet reaches the muxer whithin the specified duration after the
whithin => within
> +segmenting clock time.
Simpler:
Force the segmenter to only start ...
> This way you can make the segmenter more resilient to
> +backward local time jumps, such as leap seconds or transition to standard
> time
> +from daylight savings time.
> +
> +Assuming that the delay between the packets of your source is less than 0.5
> +second you can detect a leap second by specifying 0.5 as the duration.
> +
> +Default is the maximum possible duration which means starting a new segment
> +regardless of the elapsed time since the last clock time.
> +
> @item segment_time_delta @var{delta}
> Specify the accuracy time when selecting the start time for a
> segment, expressed as a duration specification. Default value is "0".
> diff --git a/libavformat/segment.c b/libavformat/segment.c
> index bf7a8fc..d92b9c3 100644
> --- a/libavformat/segment.c
> +++ b/libavformat/segment.c
> @@ -83,6 +83,7 @@ typedef struct SegmentContext {
>
> int use_clocktime; ///< flag to cut segments at regular clock time
> int64_t clocktime_offset; //< clock offset for cutting the segments at
> regular clock time
> + int64_t clocktime_wrap_duration; //< wrapping duration considered for
> starting a new segment
> int64_t last_val; ///< remember last time for wrap around detection
> int64_t last_cut; ///< remember last cut
> int cut_pending;
> @@ -784,7 +785,7 @@ static int seg_write_packet(AVFormatContext *s, AVPacket
> *pkt)
> localtime_r(&sec, &ti);
> usecs = (int64_t)(ti.tm_hour * 3600 + ti.tm_min * 60 +
> ti.tm_sec) * 1000000 + (avgt % 1000000);
> wrapped_val = (usecs + seg->clocktime_offset) % seg->time;
> - if (seg->last_cut != usecs && wrapped_val < seg->last_val) {
> + if (seg->last_cut != usecs && wrapped_val < seg->last_val &&
> wrapped_val < seg->clocktime_wrap_duration) {
> seg->cut_pending = 1;
> seg->last_cut = usecs;
> }
> @@ -935,6 +936,7 @@ static const AVOption options[] = {
>
> { "segment_atclocktime", "set segment to be cut at clocktime",
> OFFSET(use_clocktime), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, E},
> { "segment_clocktime_offset", "set segment clocktime offset",
> OFFSET(clocktime_offset), AV_OPT_TYPE_DURATION, {.i64 = 0}, 0, 86400, E},
> + { "segment_clocktime_wrap_duration", "set segment clocktime wrapping
> duration", OFFSET(clocktime_wrap_duration), AV_OPT_TYPE_DURATION, {.i64 =
> INT_MAX}, 0, INT_MAX, E},
> { "segment_time", "set segment duration",
> OFFSET(time_str),AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, E },
> { "segment_time_delta","set approximation value used for the segment
> times", OFFSET(time_delta), AV_OPT_TYPE_DURATION, {.i64 = 0}, 0, 0, E },
> { "segment_times", "set segment split time points",
> OFFSET(times_str),AV_OPT_TYPE_STRING,{.str = NULL}, 0, 0, E },
> --
> 2.6.2
LGTM otherwise, although I wonder if we could provide a more robust
mechanism to detect such issues.
--
FFmpeg = Faithful and Foolish Mournful Pitiful Elected Gargoyle
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