avformat/utils: Move av_find_default_stream_index to avformat.c

While it is clearly written with demuxers in mind,
it is not forbidden to call it with muxers, hence avformat.c
and not demux_utils.c.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/libavformat/avformat.c b/libavformat/avformat.c
index e3dad1f9a5..2b012a903f 100644
--- a/libavformat/avformat.c
+++ b/libavformat/avformat.c
@@ -276,6 +276,42 @@ AVProgram *av_find_program_from_stream(AVFormatContext *ic, AVProgram *last, int
     return NULL;
 }
 
+int av_find_default_stream_index(AVFormatContext *s)
+{
+    int best_stream = 0;
+    int best_score = INT_MIN;
+
+    if (s->nb_streams <= 0)
+        return -1;
+    for (unsigned i = 0; i < s->nb_streams; i++) {
+        const AVStream *const st = s->streams[i];
+        const FFStream *const sti = cffstream(st);
+        int score = 0;
+        if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
+            if (st->disposition & AV_DISPOSITION_ATTACHED_PIC)
+                score -= 400;
+            if (st->codecpar->width && st->codecpar->height)
+                score += 50;
+            score+= 25;
+        }
+        if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
+            if (st->codecpar->sample_rate)
+                score += 50;
+        }
+        if (sti->codec_info_nb_frames)
+            score += 12;
+
+        if (st->discard != AVDISCARD_ALL)
+            score += 200;
+
+        if (score > best_score) {
+            best_score = score;
+            best_stream = i;
+        }
+    }
+    return best_stream;
+}
+
 /**
  * Matches a stream specifier (but ignores requested index).
  *