@@ -13,6 +13,9 @@ libavutil:   2009-03-08

 API changes, most recent first:

+2010-12-XX - r26104 - lavformat 52.91.0 - av_find_best_stream()

+  Add av_find_best_stream to libavformat/avformat.h.

+

 2010-12-27 - r26103 - lavf 52.90.0

   Add AVFMT_NOSTREAMS flag for formats with no streams,

   like e.g. text metadata.

@@ -22,7 +22,7 @@

 #define AVFORMAT_AVFORMAT_H

 #define LIBAVFORMAT_VERSION_MAJOR 52

-#define LIBAVFORMAT_VERSION_MINOR 90

+#define LIBAVFORMAT_VERSION_MINOR 91

 #define LIBAVFORMAT_VERSION_MICRO  0

 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \

@@ -1141,6 +1141,37 @@ AVFormatContext *avformat_alloc_context(void);

 int av_find_stream_info(AVFormatContext *ic);

 /**

+ * Find the "best" stream in the file.

+ * The best stream is determined according to various heuristics as the most

+ * likely to be what the user expects.

+ * If the decoder parameter is non-NULL, av_find_best_stream will find the

+ * default decoder for the stream's codec; streams for which no decoder can

+ * be found are ignored.

+ *

+ * @param ic                media file handle

+ * @param type              stream type: video, audio, subtitles, etc.

+ * @param wanted_stream_nb  user-requested stream number,

+ *                          or -1 for automatic selection

+ * @param related_stream    try to find a stream related (eg. in the same

+ *                          program) to this one, or -1 if none

+ * @param decoder_ret       if non-NULL, returns the decoder for the

+ *                          selected stream

+ * @param flags             flags; none are currently defined

+ * @return  the non-negative stream number in case of success,

+ *          AVERROR_STREAM_NOT_FOUND if no stream with the requested type

+ *          could be found,

+ *          AVERROR_DECODER_NOT_FOUND if streams were found but no decoder

+ * @note  If av_find_best_stream returns successfully and decoder_ret is not

+ *        NULL, then *decoder_ret is guaranteed to be set to a valid AVCodec.

+ */

+int av_find_best_stream(AVFormatContext *ic,

+                        enum AVMediaType type,

+                        int wanted_stream_nb,

+                        int related_stream,

+                        AVCodec **decoder_ret,

+                        int flags);

+

+/**

  * Read a transport packet from a media file.

  *

  * This function is obsolete and should never be used.

@@ -2458,6 +2458,67 @@ int av_find_stream_info(AVFormatContext *ic)

     return ret;

 }

+static AVProgram *find_program_from_stream(AVFormatContext *ic, int s)

+{

+    int i, j;

+

+    for (i = 0; i < ic->nb_programs; i++)

+        for (j = 0; j < ic->programs[i]->nb_stream_indexes; j++)

+            if (ic->programs[i]->stream_index[j] == s)

+                return ic->programs[i];

+    return NULL;

+}

+

+int av_find_best_stream(AVFormatContext *ic,

+                        enum AVMediaType type,

+                        int wanted_stream_nb,

+                        int related_stream,

+                        AVCodec **decoder_ret,

+                        int flags)

+{

+    int i, nb_streams = ic->nb_streams, stream_number = 0;

+    int ret = AVERROR_STREAM_NOT_FOUND, best_count = -1;

+    unsigned *program = NULL;

+    AVCodec *decoder = NULL, *best_decoder = NULL;

+

+    if (related_stream >= 0 && wanted_stream_nb < 0) {

+        AVProgram *p = find_program_from_stream(ic, related_stream);

+        if (p) {

+            program = p->stream_index;

+            nb_streams = p->nb_stream_indexes;

+        }

+    }

+    for (i = 0; i < nb_streams; i++) {

+        AVStream *st = ic->streams[program ? program[i] : i];

+        AVCodecContext *avctx = st->codec;

+        if (avctx->codec_type != type)

+            continue;

+        if (wanted_stream_nb >= 0 && stream_number++ != wanted_stream_nb)

+            continue;

+        if (decoder_ret) {

+            decoder = avcodec_find_decoder(ic->streams[i]->codec->codec_id);

+            if (!decoder) {

+                if (ret < 0)

+                    ret = AVERROR_DECODER_NOT_FOUND;

+                continue;

+            }

+        }

+        if (best_count >= st->codec_info_nb_frames)

+            continue;

+        best_count = st->codec_info_nb_frames;

+        ret = i;

+        best_decoder = decoder;

+        if (program && i == nb_streams - 1 && ret < 0) {

+            program = NULL;

+            nb_streams = ic->nb_streams;

+            i = 0; /* no related stream found, try again with everything */

+        }

+    }

+    if (decoder_ret)

+        *decoder_ret = best_decoder;

+    return ret;

+}

+

 /*******************************************************/

 int av_read_play(AVFormatContext *s)