[FFmpeg-devel] [PATCH v2 2/6] avformat/segment: Add segment_limit option

[softworkz <ffmpegagent-at-gmail.com@ffmpeg.org>]

From: softworkz <softworkz@hotmail.com>

Example use case:

Existing segments 0-30 and 70-99, 31-69 need to be created.
This option allows to stop precisely after 69. Otherwise it would
start overwriting segment 70 before stopping via 'q' or break signal.

Signed-off-by: softworkz <softworkz@hotmail.com>
---
 doc/muxers.texi       |  7 +++++++
 libavformat/segment.c | 12 ++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/doc/muxers.texi b/doc/muxers.texi
index 6d5c17b4cc..1cca8da1fb 100644
--- a/doc/muxers.texi
+++ b/doc/muxers.texi
@@ -3510,6 +3510,13 @@ packet written. Defaults to @code{0}.
 Write segments to files with a .tmp extension. Each file is renamed to its 
 actual name on completion. This can help to prevent segment files from 
 being accessed before they are complete. Disabled by default (@code{0}).
+
+@item segment_limit @var{number}
+Stops after the specified number of segments has been generated.
+This can be helpful to fill gaps in a range of already generated segments,
+which is difficult to achieve otherwise as it would either cause the last 
+segment to be incomplete or to overwrite an existing segment with a partial
+data. Default is @code{0} - no limit.
 @end table
 
 Make sure to require a closed GOP when encoding and to set the GOP
diff --git a/libavformat/segment.c b/libavformat/segment.c
index 14eba90292..e8b1582e7d 100644
--- a/libavformat/segment.c
+++ b/libavformat/segment.c
@@ -121,6 +121,8 @@ typedef struct SegmentContext {
     int   break_non_keyframes;
     int   write_empty;
 
+    int segment_limit;       ///< max number of segments to create
+
     int segment_write_temp; ///< write segments as temp files and rename on completion
     int use_rename;
     char temp_list_filename[1024];
@@ -365,6 +367,9 @@ static int segment_end(AVFormatContext *s, int write_trailer, int is_last)
     int i;
     int err;
 
+    if (seg->segment_limit && seg->segment_count >= seg->segment_limit)
+        return 0;
+
     if (!oc || !oc->pb)
         return AVERROR(EINVAL);
 
@@ -879,6 +884,9 @@ static int seg_write_packet(AVFormatContext *s, AVPacket *pkt)
     int64_t usecs;
     int64_t wrapped_val;
 
+    if (seg->segment_limit && seg->segment_count >= seg->segment_limit)
+        return 0;
+
     if (!seg->avf || !seg->avf->pb)
         return AVERROR(EINVAL);
 
@@ -953,6 +961,9 @@ calc_times:
         if ((ret = segment_end(s, seg->individual_header_trailer, 0)) < 0)
             goto fail;
 
+        if (seg->segment_limit && seg->segment_count >= seg->segment_limit)
+            return 0;
+
         if ((ret = segment_start(s, seg->individual_header_trailer)) < 0)
             goto fail;
 
@@ -1098,6 +1109,7 @@ static const AVOption options[] = {
     { "initial_offset", "set initial timestamp offset", OFFSET(initial_offset), AV_OPT_TYPE_DURATION, {.i64 = 0}, -INT64_MAX, INT64_MAX, E },
     { "write_empty_segments", "allow writing empty 'filler' segments", OFFSET(write_empty), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, E },
     { "segment_write_temp", "write segments as temp files (.tmp) and rename on completion", OFFSET(segment_write_temp), AV_OPT_TYPE_BOOL,   {.i64 = 0}, 0, 1, E }, 
+    { "segment_limit", "stop output once the specified number of segments has been written", OFFSET(segment_limit), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, E },
     { NULL },
 };
 
-- 
ffmpeg-codebot

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