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author | Stefano Sabatini <stefasab@gmail.com> | 2012-01-28 22:21:43 +0100 |
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committer | Stefano Sabatini <stefasab@gmail.com> | 2012-07-10 00:53:01 +0200 |
commit | aef9e94f73b9e5e21f7a790343e0b4ffb9e2acee (patch) | |
tree | eb387647f758c3e07baa8a51d6fce7edc789fbbb | |
parent | 2058b52cf8a4eea9bf046f72b98e89fe9b36d3e3 (diff) | |
download | ffmpeg-aef9e94f73b9e5e21f7a790343e0b4ffb9e2acee.tar.gz |
lavf/segment: add -segment_time_delta option
-rw-r--r-- | doc/muxers.texi | 34 | ||||
-rw-r--r-- | libavformat/segment.c | 14 | ||||
-rw-r--r-- | libavformat/version.h | 2 |
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, \ |