@@ -474,6 +474,28 @@ the segment start and end time expressed in seconds.

 Default value is "flat".

 @item segment_time @var{time}

 Set segment duration to @var{time}. Default value is "2".

+@item segment_time_delta @var{delta}

+Specify the accuracy time when selecting the start time for a

+segment. Default value is "0".

+

+When delta is specified a key-frame will start a new segment if its

+PTS satisfies the relation:

+@example

+PTS >= start_time - time_delta

+@end example

+

+This option is useful when splitting video content, which is always

+split at GOP boundaries, in case a key frame is found just before the

+specified split time.

+

+In particular may be used in combination with the @file{ffmpeg} option

+@var{force_key_frames}. The key frame times specified by

+@var{force_key_frames} may not be set accurately because of rounding

+issues, with the consequence that a key frame time may result set just

+before the specified time. For constant frame rate videos a value of

+1/2*@var{frame_rate} should address the worst case mismatch between

+the specified time and the time set by @var{force_key_frames}.

+

 @item segment_times @var{times}

 Specify a list of split points. @var{times} contains a list of comma

 separated duration specifications, in increasing order.

@@ -500,6 +522,18 @@ ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list_type ext -segment_l

 @end example

 @item

+As the example above, but use the @code{ffmpeg} @var{force_key_frames}

+option to force key frames in the input at the specified location, together

+with the segment option @var{segment_time_delta} to account for

+possible roundings operated when setting key frame times.

+@example

+ffmpeg -i in.mkv -force_key_frames 1,2,3,5,8,13,21 -vcodec mpeg4 -acodec pcm_s16le -map 0 \

+-f segment -segment_list_type ext -segment_list out.list -segment_list_size 0 -segment_times 1,2,3,5,8,13,21 -segment_time_delta 0.05 out%03d.nut

+@end example

+In order to force key frames on the input file, transcoding is

+required.

+

+@item

 To convert the @file{in.mkv} to TS segments using the @code{libx264}

 and @code{libfaac} encoders:

 @example

@@ -52,6 +52,8 @@ typedef struct {

     char *times_str;       ///< segment times specification string

     int64_t *times;        ///< list of segment interval specification

     int nb_times;          ///< number of elments in the times array

+    char *time_delta_str;  ///< approximation value duration used for the segment times

+    int64_t time_delta;

     int has_video;

     double start_time, end_time;

 } SegmentContext;

@@ -222,6 +224,15 @@ static int seg_write_header(AVFormatContext *s)

         }

     }

+    if (seg->time_delta_str) {

+        if ((ret = av_parse_time(&seg->time_delta, seg->time_delta_str, 1)) < 0) {

+            av_log(s, AV_LOG_ERROR,

+                   "Invalid time duration specification '%s' for delta option\n",

+                   seg->time_delta_str);

+            return ret;

+        }

+    }

+

     oc = avformat_alloc_context();

     if (!oc)

@@ -304,7 +315,7 @@ static int seg_write_packet(AVFormatContext *s, AVPacket *pkt)

     /* if the segment has video, start a new segment *only* with a key video frame */

     if ((st->codec->codec_type == AVMEDIA_TYPE_VIDEO || !seg->has_video) &&

         av_compare_ts(pkt->pts, st->time_base,

-                      end_pts, AV_TIME_BASE_Q) >= 0 &&

+                      end_pts-seg->time_delta, AV_TIME_BASE_Q) >= 0 &&

         pkt->flags & AV_PKT_FLAG_KEY) {

         av_log(s, AV_LOG_DEBUG, "Next segment starts with packet stream:%d pts:%"PRId64" pts_time:%f\n",

@@ -359,6 +370,7 @@ static const AVOption options[] = {

     { "flat", "flat format",     0, AV_OPT_TYPE_CONST, {.dbl=LIST_TYPE_FLAT }, INT_MIN, INT_MAX, 0, "list_type" },

     { "ext",  "extended format", 0, AV_OPT_TYPE_CONST, {.dbl=LIST_TYPE_EXT  }, INT_MIN, INT_MAX, 0, "list_type" },

     { "segment_time",      "set segment duration",                       OFFSET(time_str),AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,       E },

+    { "segment_time_delta","set approximation value used for the segment times", OFFSET(time_delta_str), AV_OPT_TYPE_STRING, {.str = "0"}, 0, 0, E },

     { "segment_times",     "set segment split time points",              OFFSET(times_str),AV_OPT_TYPE_STRING,{.str = NULL},  0, 0,       E },

     { "segment_wrap",      "set number after which the index wraps",     OFFSET(wrap),    AV_OPT_TYPE_INT,    {.dbl = 0},     0, INT_MAX, E },

     { NULL },

@@ -31,7 +31,7 @@

 #define LIBAVFORMAT_VERSION_MAJOR 54

 #define LIBAVFORMAT_VERSION_MINOR 15

-#define LIBAVFORMAT_VERSION_MICRO 103

+#define LIBAVFORMAT_VERSION_MICRO 104

 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \

                                                LIBAVFORMAT_VERSION_MINOR, \