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

[Gyan Doshi <ffmpeg@gyani.pro>]

Plan to push tomorrow.

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.
>>   +@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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