[FFmpeg-devel] [PATCH] lavf/segment: add option to write empty filler segments as needed

[Stefano Sabatini]

On date Monday 2015-12-07 14:24:44 -0600, Rodger Combs encoded:
> ---
>  libavformat/segment.c | 22 +++++++++++++++-------
>  1 file changed, 15 insertions(+), 7 deletions(-)

Missing docs.
 
> diff --git a/libavformat/segment.c b/libavformat/segment.c
> index 8432d0f..acd266b 100644
> --- a/libavformat/segment.c
> +++ b/libavformat/segment.c
> @@ -113,6 +113,7 @@ typedef struct SegmentContext {
>      char *reference_stream_specifier; ///< reference stream specifier
>      int   reference_stream_index;
>      int   break_non_keyframes;
> +    int   write_empty;
>  
>      int use_rename;
>      char temp_list_filename[1024];
> @@ -763,6 +764,7 @@ static int seg_write_packet(AVFormatContext *s, AVPacket *pkt)
>      if (!seg->avf)
>          return AVERROR(EINVAL);
>  
> +calc_times:
>      if (seg->times) {
>          end_pts = seg->segment_count < seg->nb_times ?
>              seg->times[seg->segment_count] : INT64_MAX;
> @@ -794,11 +796,11 @@ static int seg_write_packet(AVFormatContext *s, AVPacket *pkt)
>  
>      if (pkt->stream_index == seg->reference_stream_index &&
>          (pkt->flags & AV_PKT_FLAG_KEY || seg->break_non_keyframes) &&
> -        seg->segment_frame_count > 0 &&
> +        (seg->segment_frame_count > 0 || seg->write_empty) &&
>          (seg->cut_pending || seg->frame_count >= start_frame ||
>           (pkt->pts != AV_NOPTS_VALUE &&

>            av_compare_ts(pkt->pts, st->time_base,
> -                        end_pts-seg->time_delta, AV_TIME_BASE_Q) >= 0))) {
> +                        end_pts - seg->time_delta, AV_TIME_BASE_Q) >= 0))) {

unrelated

>          /* sanitize end time in case last packet didn't have a defined duration */
>          if (seg->cur_entry.last_duration == 0)
>              seg->cur_entry.end_time = (double)pkt->pts * av_q2d(st->time_base);
> @@ -813,11 +815,16 @@ static int seg_write_packet(AVFormatContext *s, AVPacket *pkt)
>          seg->cur_entry.index = seg->segment_idx + seg->segment_idx_wrap * seg->segment_idx_wrap_nb;
>          seg->cur_entry.start_time = (double)pkt->pts * av_q2d(st->time_base);
>          seg->cur_entry.start_pts = av_rescale_q(pkt->pts, st->time_base, AV_TIME_BASE_Q);
> -        seg->cur_entry.end_time = seg->cur_entry.start_time +
> -            pkt->pts != AV_NOPTS_VALUE ? (double)(pkt->pts + pkt->duration) * av_q2d(st->time_base) : 0;
> -    } else if (pkt->pts != AV_NOPTS_VALUE && pkt->stream_index == seg->reference_stream_index) {
> -        seg->cur_entry.end_time =
> -            FFMAX(seg->cur_entry.end_time, (double)(pkt->pts + pkt->duration) * av_q2d(st->time_base));
> +        seg->cur_entry.end_time = seg->cur_entry.start_time;
> +

> +        if (seg->times || (!seg->frames && !seg->use_clocktime) && seg->write_empty)
> +            goto calc_times;

I dislike this goto here, since I'd like to keep the distinction between
the logic setting end_pts/start_frame and the one selecting whether to
close the segment.

> +    }
> +

> +    if (pkt->stream_index == seg->reference_stream_index) {
> +        if (pkt->pts != AV_NOPTS_VALUE)
> +            seg->cur_entry.end_time =
> +                FFMAX(seg->cur_entry.end_time, (double)(pkt->pts + pkt->duration) * av_q2d(st->time_base));

This factorization is fine, but should be probably sent as a separate patch.

[...]

Thanks.
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