[FFmpeg-devel] [PATCH 3/3] lavf/segment: add option to write empty filler segments as needed

[Stefano Sabatini]

On date Sunday 2016-03-06 20:49:24 -0600, Rodger Combs encoded:
> ---
>  doc/muxers.texi       | 5 +++++
>  libavformat/segment.c | 8 +++++++-
>  2 files changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/doc/muxers.texi b/doc/muxers.texi
> index f2ad7fe..700ec88 100644
> --- a/doc/muxers.texi
> +++ b/doc/muxers.texi
> @@ -1224,6 +1224,11 @@ muxers/codecs. It is set to @code{0} by default.
>  @item initial_offset @var{offset}
>  Specify timestamp offset to apply to the output packet timestamps. The
>  argument must be a time duration specification, and defaults to 0.
> +
> + at item write_empty_segments @var{1|0}
> +If enabled, write an empty segment if there are no packets during the period a
> +segment would usually span. Otherwise, the segment will be filled with the next
> +packet written. Defaults to @code{0}.
>  @end table

Can you describe an use case for this (and possibly add a short
description in the log)?

>  
>  @subsection Examples
> diff --git a/libavformat/segment.c b/libavformat/segment.c
> index 6ad991f..df1514f 100644
> --- a/libavformat/segment.c
> +++ b/libavformat/segment.c
> @@ -116,6 +116,7 @@ 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];
> @@ -774,6 +775,7 @@ 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;
> @@ -805,7 +807,7 @@ 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,
> @@ -825,6 +827,9 @@ static int seg_write_packet(AVFormatContext *s, AVPacket *pkt)
>          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;
> +

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

what's the point of this goto?

[...]
-- 
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