[FFmpeg-devel] [PATCH] avformat/segment: add option min_seg_duration

[Gyan Doshi]

On 2022-12-28 09:26 am, Gyan Doshi wrote:
> Plan to push tomorrow.

Pushed as d39b34123daadce3c7db2851120cf10b4c3511db with a small change 
to ensure this is limited to segment_time.

>
> On 2022-12-25 11:54 pm, Gyan Doshi wrote:
>>
>>
>> On 2022-12-21 09:08 pm, Gyan Doshi wrote:
>>> New option can be used to avoid creating very short segments with 
>>> inputs
>>> whose GOP size is variable or unharmonic with segment_time.
>>>
>>> Only effective with segment_time.
>> Comments?
>>
>>> ---
>>>   doc/muxers.texi       |  5 +++++
>>>   libavformat/segment.c | 12 +++++++++++-
>>>   2 files changed, 16 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/doc/muxers.texi b/doc/muxers.texi
>>> index 4edbb22b00..ed5341be39 100644
>>> --- a/doc/muxers.texi
>>> +++ b/doc/muxers.texi
>>> @@ -2369,6 +2369,11 @@ Note that splitting may not be accurate, 
>>> unless you force the
>>>   reference stream key-frames at the given time. See the introductory
>>>   notice and the examples below.
>>>   + at item min_seg_duration @var{time}
>>> +Set minimum segment duration to @var{time}, the value must be a 
>>> duration
>>> +specification. This prevents the muxer ending segments at a 
>>> duration below
>>> +this value. Only effective with @code{segment_time}. Default value 
>>> is "0".
>>> +
>>>   @item segment_atclocktime @var{1|0}
>>>   If set to "1" split at regular clock time intervals starting from 
>>> 00:00
>>>   o'clock. The @var{time} value specified in @option{segment_time} is
>>> diff --git a/libavformat/segment.c b/libavformat/segment.c
>>> index c904e20708..c19c2a94ae 100644
>>> --- a/libavformat/segment.c
>>> +++ b/libavformat/segment.c
>>> @@ -93,6 +93,7 @@ typedef struct SegmentContext {
>>>       int list_type;         ///< set the list type
>>>       AVIOContext *list_pb;  ///< list file put-byte context
>>>       int64_t time;          ///< segment duration
>>> +    int64_t min_seg_duration;  ///< minimum segment duration
>>>       int use_strftime;      ///< flag to expand filename with strftime
>>>       int increment_tc;      ///< flag to increment timecode if found
>>>   @@ -710,6 +711,10 @@ static int seg_init(AVFormatContext *s)
>>>               }
>>>               seg->clocktime_offset = seg->time - 
>>> (seg->clocktime_offset % seg->time);
>>>           }
>>> +        if (seg->min_seg_duration > seg->time) {
>>> +            av_log(s, AV_LOG_ERROR, "min_seg_duration cannot be 
>>> greater than segment_time\n");
>>> +            return AVERROR(EINVAL);
>>> +        }
>>>       }
>>>         if (seg->list) {
>>> @@ -839,7 +844,7 @@ static int seg_write_packet(AVFormatContext *s, 
>>> AVPacket *pkt)
>>>   {
>>>       SegmentContext *seg = s->priv_data;
>>>       AVStream *st = s->streams[pkt->stream_index];
>>> -    int64_t end_pts = INT64_MAX, offset;
>>> +    int64_t end_pts = INT64_MAX, offset, pkt_pts_avtb;
>>>       int start_frame = INT_MAX;
>>>       int ret;
>>>       struct tm ti;
>>> @@ -890,11 +895,15 @@ calc_times:
>>>               pkt->flags & AV_PKT_FLAG_KEY,
>>>               pkt->stream_index == seg->reference_stream_index ? 
>>> seg->frame_count : -1);
>>>   +    if (pkt->pts != AV_NOPTS_VALUE)
>>> +        pkt_pts_avtb = av_rescale_q(pkt->pts, st->time_base, 
>>> AV_TIME_BASE_Q);
>>> +
>>>       if (pkt->stream_index == seg->reference_stream_index &&
>>>           (pkt->flags & AV_PKT_FLAG_KEY || seg->break_non_keyframes) &&
>>>           (seg->segment_frame_count > 0 || seg->write_empty) &&
>>>           (seg->cut_pending || seg->frame_count >= start_frame ||
>>>            (pkt->pts != AV_NOPTS_VALUE &&
>>> +          pkt_pts_avtb - seg->cur_entry.start_pts >= 
>>> seg->min_seg_duration &&
>>>             av_compare_ts(pkt->pts, st->time_base,
>>>                           end_pts - seg->time_delta, AV_TIME_BASE_Q) 
>>> >= 0))) {
>>>           /* sanitize end time in case last packet didn't have a 
>>> defined duration */
>>> @@ -1031,6 +1040,7 @@ static const AVOption options[] = {
>>>       { "segment_clocktime_wrap_duration", "set segment clocktime 
>>> wrapping duration", OFFSET(clocktime_wrap_duration), 
>>> AV_OPT_TYPE_DURATION, {.i64 = INT64_MAX}, 0, INT64_MAX, E},
>>>       { "segment_time",      "set segment duration", 
>>> OFFSET(time),AV_OPT_TYPE_DURATION, {.i64 = 2000000}, INT64_MIN, 
>>> INT64_MAX,       E },
>>>       { "segment_time_delta","set approximation value used for the 
>>> segment times", OFFSET(time_delta), AV_OPT_TYPE_DURATION, {.i64 = 
>>> 0}, 0, INT64_MAX, E },
>>> +    { "min_seg_duration",  "set minimum segment 
>>> duration",               OFFSET(min_seg_duration), 
>>> AV_OPT_TYPE_DURATION, {.i64 = 0}, 0, INT64_MAX, E },
>>>       { "segment_times",     "set segment split time points", 
>>> OFFSET(times_str),AV_OPT_TYPE_STRING,{.str = NULL},  0, 0,       E },
>>>       { "segment_frames",    "set segment split frame numbers", 
>>> OFFSET(frames_str),AV_OPT_TYPE_STRING,{.str = NULL},  0, 0,       E },
>>>       { "segment_wrap",      "set number after which the index 
>>> wraps",     OFFSET(segment_idx_wrap), AV_OPT_TYPE_INT, {.i64 = 0}, 
>>> 0, INT_MAX, E },
>>
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