lavf: move RIFF INFO tag writing from avienc to riff

It will be useful in the wav muxer.
Signed-off-by: Anton Khirnov <anton@khirnov.net>

libavformat/avienc.c

@@ -105,19 +105,6 @@ static char* avi_stream2fourcc(char* tag, int index, enum AVMediaType type)
     return tag;
 }
 
-static void avi_write_info_tag(AVIOContext *pb, const char *tag, const char *str)
-{
-    int len = strlen(str);
-    if (len > 0) {
-        len++;
-        ffio_wfourcc(pb, tag);
-        avio_wl32(pb, len);
-        avio_put_str(pb, str);
-        if (len & 1)
-            avio_w8(pb, 0);
-    }
-}
-
 static int avi_write_counters(AVFormatContext* s, int riff_id)
 {
     AVIOContext *pb = s->pb;
@@ -300,7 +287,7 @@ static int avi_write_header(AVFormatContext *s)
         }
         ff_end_tag(pb, strf);
         if ((t = av_dict_get(s->streams[i]->metadata, "title", NULL, 0))) {
-            avi_write_info_tag(s->pb, "strn", t->value);
+            ff_riff_write_info_tag(s->pb, "strn", t->value);
             t = NULL;
         }
       }
@@ -377,14 +364,7 @@ static int avi_write_header(AVFormatContext *s)
 
     ff_end_tag(pb, list1);
 
-    list2 = ff_start_tag(pb, "LIST");
-    ffio_wfourcc(pb, "INFO");
-    ff_metadata_conv(&s->metadata, ff_riff_info_conv, NULL);
-    for (i = 0; *ff_riff_tags[i]; i++) {
-        if ((t = av_dict_get(s->metadata, ff_riff_tags[i], NULL, AV_DICT_MATCH_CASE)))
-            avi_write_info_tag(s->pb, t->key, t->value);
-    }
-    ff_end_tag(pb, list2);
+    ff_riff_write_info(s);
 
     /* some padding for easier tag editing */
     list2 = ff_start_tag(pb, "JUNK");

libavformat/riff.c

 /*
- * RIFF codec tags
+ * RIFF common functions and data
  * Copyright (c) 2000 Fabrice Bellard
  *
  * This file is part of Libav.
@@ -708,3 +708,33 @@ int ff_read_riff_info(AVFormatContext *s, int64_t size)
 
     return 0;
 }
+
+void ff_riff_write_info_tag(AVIOContext *pb, const char *tag, const char *str)
+{
+    int len = strlen(str);
+    if (len > 0) {
+        len++;
+        ffio_wfourcc(pb, tag);
+        avio_wl32(pb, len);
+        avio_put_str(pb, str);
+        if (len & 1)
+            avio_w8(pb, 0);
+    }
+}
+
+void ff_riff_write_info(AVFormatContext *s)
+{
+    AVIOContext *pb = s->pb;
+    int i;
+    int64_t list_pos;
+    AVDictionaryEntry *t = NULL;
+
+    list_pos = ff_start_tag(pb, "LIST");
+    ffio_wfourcc(pb, "INFO");
+    ff_metadata_conv(&s->metadata, ff_riff_info_conv, NULL);
+    for (i = 0; *ff_riff_tags[i]; i++) {
+        if ((t = av_dict_get(s->metadata, ff_riff_tags[i], NULL, AV_DICT_MATCH_CASE)))
+            ff_riff_write_info_tag(s->pb, t->key, t->value);
+    }
+    ff_end_tag(pb, list_pos);
+}

libavformat/riff.h

 /*
- * RIFF codec tags
+ * RIFF common functions and data
  * copyright (c) 2000 Fabrice Bellard
  *
  * This file is part of Libav.
@@ -60,4 +60,14 @@ void ff_parse_specific_params(AVCodecContext *stream, int *au_rate, int *au_ssiz
 
 int ff_read_riff_info(AVFormatContext *s, int64_t size);
 
+/**
+ * Write all recognized RIFF tags from s->metadata
+ */
+void ff_riff_write_info(AVFormatContext *s);
+
+/**
+ * Write a single RIFF info tag
+ */
+void ff_riff_write_info_tag(AVIOContext *pb, const char *tag, const char *str);
+
 #endif /* AVFORMAT_RIFF_H */