lavf/segment: move reference stream selection code to a dedicated function

libavformat/segment.c

@@ -451,11 +451,66 @@ static void close_null_ctx(AVIOContext *pb)
     av_free(pb);
 }
 
+static int select_reference_stream(AVFormatContext *s)
+{
+    SegmentContext *seg = s->priv_data;
+    int ret, i;
+
+    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)
+                break;
+            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);
+        return AVERROR(EINVAL);
+    }
+
+    return 0;
+}
+
 static int seg_write_header(AVFormatContext *s)
 {
     SegmentContext *seg = s->priv_data;
     AVFormatContext *oc = NULL;
-    int ret, i;
+    int ret;
 
     seg->segment_count = 0;
     if (!seg->write_header_trailer)
@@ -515,54 +570,8 @@ 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");
 
-    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);
+    if ((ret = select_reference_stream(s)) < 0)
         goto fail;
-    }
-
     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));