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authorStefano Sabatini <stefasab@gmail.com>2012-01-28 22:21:43 +0100
committerStefano Sabatini <stefasab@gmail.com>2012-07-10 00:53:01 +0200
commitaef9e94f73b9e5e21f7a790343e0b4ffb9e2acee (patch)
treeeb387647f758c3e07baa8a51d6fce7edc789fbbb
parent2058b52cf8a4eea9bf046f72b98e89fe9b36d3e3 (diff)
downloadffmpeg-aef9e94f73b9e5e21f7a790343e0b4ffb9e2acee.tar.gz
lavf/segment: add -segment_time_delta option
-rw-r--r--doc/muxers.texi34
-rw-r--r--libavformat/segment.c14
-rw-r--r--libavformat/version.h2
3 files changed, 48 insertions, 2 deletions
diff --git a/doc/muxers.texi b/doc/muxers.texi
index 7934fe2c89..aee90b53ce 100644
--- a/doc/muxers.texi
+++ b/doc/muxers.texi
@@ -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
diff --git a/libavformat/segment.c b/libavformat/segment.c
index 32b38b1bba..f96398b6c7 100644
--- a/libavformat/segment.c
+++ b/libavformat/segment.c
@@ -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 },
diff --git a/libavformat/version.h b/libavformat/version.h
index 36c8da54c8..e0d8061038 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -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, \