@@ -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

+@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 must a stream specifier (see the ``Stream

+specifiers'' chapter in the ffmpeg manual) which specifies the

+reference stream. The default value is ``auto''.

+

 @item segment_format @var{format}

 Override the inner container format, by default it is guessed by the filename

 extension.

@@ -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 +400,57 @@ 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")) {

+        /* select first index of type with highest priority */

+        int type_index_map[AVMEDIA_TYPE_NB];

+        static const enum AVMediaType type_priority_list[] = {

+            AVMEDIA_TYPE_VIDEO,

+            AVMEDIA_TYPE_AUDIO,

+            AVMEDIA_TYPE_SUBTITLE,

+            AVMEDIA_TYPE_DATA,

+            AVMEDIA_TYPE_ATTACHMENT

+        };

+        enum AVMediaType type;

+

+        for (i = 0; i < AVMEDIA_TYPE_NB; i++)

+            type_index_map[i] = -1;

+

+        /* select first index for each type */

+        for (i = 0; i < s->nb_streams; i++) {

+            type = s->streams[i]->codec->codec_type;

+            if ((unsigned)type < AVMEDIA_TYPE_NB && type_index_map[type] == -1)

+                type_index_map[type] = i;

+        }

+

+        for (i = 0; i < FF_ARRAY_ELEMS(type_priority_list); i++) {

+            type = type_priority_list[i];

+            if ((seg->reference_stream_index = type_index_map[type]) >= 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);

@@ -478,8 +523,7 @@ 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->pts != AV_NOPTS_VALUE &&

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

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

@@ -565,6 +609,7 @@ 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 },

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

 #define LIBAVFORMAT_VERSION_MAJOR 54

 #define LIBAVFORMAT_VERSION_MINOR 50

-#define LIBAVFORMAT_VERSION_MICRO 102

+#define LIBAVFORMAT_VERSION_MICRO 103

 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \

                                                LIBAVFORMAT_VERSION_MINOR, \