[FFmpeg-devel] [PATCH] lavf/segment: add reference_stream option
Stefano Sabatini
stefasab at gmail.com
Sat Dec 22 23:59:11 CET 2012
---
doc/muxers.texi | 11 ++++++++-
libavformat/segment.c | 64 +++++++++++++++++++++++++++++++++++++++----------
2 files changed, 61 insertions(+), 14 deletions(-)
diff --git a/doc/muxers.texi b/doc/muxers.texi
index 25cf565..e8c4a52 100644
--- a/doc/muxers.texi
+++ b/doc/muxers.texi
@@ -493,7 +493,9 @@ streaming output formats, i.e. which do not require global headers,
and is recommended for outputting e.g. to MPEG transport stream segments.
@code{ssegment} is a shorter alias for @code{stream_segment}.
-Every segment starts with a video keyframe, if a video stream is present.
+Every segment starts with a keyframe of the selected reference stream,
+which is set through the @option{reference_stream} option.
+
Note that if you want accurate splitting for a video file, you need to
make the input key frames correspond to the exact splitting times
expected by the segmenter, or the segment muxer will start the new
@@ -509,6 +511,13 @@ the option @var{segment_list}. The list type is specified by the
The segment muxer supports the following options:
@table @option
+ at item reference_stream @var{specifier}
+Set the reference stream, as specified by the string @var{specifier}.
+If @var{specifier} is set to @code{auto}, the reference is choosen
+automatically. Otherwise it is a stream specifier (see the ``Stream
+specifiers'' chapter in the ffmpeg manual). The default value is
+``auto''.
+
@item segment_format @var{format}
Override the inner container format, by default it is guessed by the filename
extension.
diff --git a/libavformat/segment.c b/libavformat/segment.c
index dc9b9c8..b46de10 100644
--- a/libavformat/segment.c
+++ b/libavformat/segment.c
@@ -74,7 +74,9 @@ typedef struct {
int write_header_trailer; /**< Set by a private option. */
int reset_timestamps; ///< reset timestamps at the begin of each segment
- int has_video;
+ char *reference_stream_specifier; ///< reference stream specifier
+ int reference_stream_index;
+
double start_time, end_time;
int64_t start_pts, start_dts;
int is_first_pkt; ///< tells if it is the first packet in the segment
@@ -398,14 +400,51 @@ static int seg_write_header(AVFormatContext *s)
if (seg->list_type == LIST_TYPE_EXT)
av_log(s, AV_LOG_WARNING, "'ext' list type option is deprecated in favor of 'csv'\n");
- for (i = 0; i < s->nb_streams; i++)
- seg->has_video +=
- (s->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO);
+ seg->reference_stream_index = -1;
+ if (!strcmp(seg->reference_stream_specifier, "auto")) {
+ int first_id[AVMEDIA_TYPE_NB];
+
+ for (i = 0; i < AVMEDIA_TYPE_NB; i++)
+ first_id[i] = -1;
+
+ for (i = 0; i < s->nb_streams; i++) {
+ enum AVMediaType type_priority_list[] = {
+ AVMEDIA_TYPE_VIDEO,
+ AVMEDIA_TYPE_AUDIO,
+ AVMEDIA_TYPE_SUBTITLE,
+ AVMEDIA_TYPE_DATA,
+ AVMEDIA_TYPE_ATTACHMENT
+ };
+ enum AVMediaType type = s->streams[i]->codec->codec_type;
+ first_id[type] = FFMAX(first_id[type], i);
+
+ for (i = 0; i < FF_ARRAY_ELEMS(type_priority_list); i++)
+ if ((seg->reference_stream_index = first_id[i]) >= 0)
+ break;
+ }
+ } else {
+ for (i = 0; i < s->nb_streams; i++) {
+ ret = avformat_match_stream_specifier(s, s->streams[i],
+ seg->reference_stream_specifier);
+ if (ret < 0)
+ goto fail;
+ if (ret > 0) {
+ seg->reference_stream_index = i;
+ break;
+ }
+ }
+ }
+
+ if (seg->reference_stream_index < 0) {
+ av_log(s, AV_LOG_ERROR, "Could not select stream matching identifier '%s'\n",
+ seg->reference_stream_specifier);
+ ret = AVERROR(EINVAL);
+ goto fail;
+ }
- if (seg->has_video > 1)
- av_log(s, AV_LOG_WARNING,
- "More than a single video stream present, "
- "expect issues decoding it.\n");
+ av_log(s, AV_LOG_VERBOSE, "Selected stream id:%d type:%s\n",
+ seg->reference_stream_index,
+ av_get_media_type_string(s->streams[seg->reference_stream_index]->codec->codec_type));
seg->oformat = av_guess_format(seg->format, s->filename, NULL);
@@ -478,12 +517,10 @@ static int seg_write_packet(AVFormatContext *s, AVPacket *pkt)
end_pts = seg->time * seg->segment_count;
}
- /* 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) &&
+ if (pkt->stream_index == seg->reference_stream_index &&
+ pkt->flags & AV_PKT_FLAG_KEY &&
pkt->pts != AV_NOPTS_VALUE &&
- av_compare_ts(pkt->pts, st->time_base,
- end_pts-seg->time_delta, AV_TIME_BASE_Q) >= 0 &&
- pkt->flags & AV_PKT_FLAG_KEY) {
+ av_compare_ts(pkt->pts, st->time_base, end_pts-seg->time_delta, AV_TIME_BASE_Q) >= 0) {
ret = segment_end(s, seg->individual_header_trailer);
if (!ret)
@@ -565,6 +602,7 @@ fail:
#define OFFSET(x) offsetof(SegmentContext, x)
#define E AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
+ { "reference_stream", "set reference stream", OFFSET(reference_stream_specifier), AV_OPT_TYPE_STRING, {.str = "auto"}, CHAR_MIN, CHAR_MAX, E },
{ "segment_format", "set container format used for the segments", OFFSET(format), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, E },
{ "segment_list", "set the segment list filename", OFFSET(list), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, E },
--
1.7.9.5
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