modify the way to pass parameters to av_metadata_set()

This improves code readability and this avoid warnings about discarding
qualifiers from pointer target type.

Originally committed as revision 16952 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/avformat.h

@@ -89,10 +89,11 @@ av_metadata_get(AVMetadata *m, const char *key, const AVMetadataTag *prev, int f
 
 /**
  * sets the given tag in m, overwriting an existing tag.
- * @param tag tag to add to m, key and value will be av_strduped.
+ * @param key tag key to add to m (will be av_strduped).
+ * @param value tag value to add to m (will be av_strduped).
  * @return >= 0 if success otherwise error code that is <0.
  */
-int av_metadata_set(AVMetadata **m, AVMetadataTag tag);
+int av_metadata_set(AVMetadata **pm, const char *key, const char *value);
 
 /**
  * Free all the memory allocated for an AVMetadata struct.

libavformat/avidec.c

@@ -229,7 +229,7 @@ static int avi_read_tag(AVFormatContext *s, const char *key, unsigned int size)
     get_strz(pb, value, sizeof(value));
     url_fseek(pb, i+size, SEEK_SET);
 
-    return av_metadata_set(&s->metadata, (const AVMetadataTag){key, value});
+    return av_metadata_set(&s->metadata, key, value);
 }
 
 static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)

libavformat/metadata.c

@@ -44,10 +44,10 @@ av_metadata_get(AVMetadata *m, const char *key, const AVMetadataTag *prev, int f
     return NULL;
 }
 
-int av_metadata_set(AVMetadata **pm, AVMetadataTag elem)
+int av_metadata_set(AVMetadata **pm, const char *key, const char *value)
 {
     AVMetadata *m= *pm;
-    AVMetadataTag *tag= av_metadata_get(m, elem.key, NULL, AV_METADATA_MATCH_CASE);
+    AVMetadataTag *tag= av_metadata_get(m, key, NULL, AV_METADATA_MATCH_CASE);
 
     if(!m)
         m=*pm= av_mallocz(sizeof(*m));
@@ -63,10 +63,10 @@ int av_metadata_set(AVMetadata **pm, AVMetadataTag elem)
         }else
             return AVERROR(ENOMEM);
     }
-    if(elem.value){
-        elem.key  = av_strdup(elem.key  );
-        elem.value= av_strdup(elem.value);
-        m->elems[m->count++]= elem;
+    if(value){
+        m->elems[m->count].key  = av_strdup(key  );
+        m->elems[m->count].value= av_strdup(value);
+        m->count++;
     }
     if(!m->count)
         av_freep(pm);

libavformat/metadata_compat.c

@@ -106,7 +106,7 @@ void ff_metadata_demux_compat(AVFormatContext *ctx)
 
 #define FILL_METADATA(s, key, value) {                                        \
     if (value && *value && !av_metadata_get(s->metadata, #key, NULL, 0))      \
-        av_metadata_set(&s->metadata, (const AVMetadataTag){#key, value});    \
+        av_metadata_set(&s->metadata, #key, value);                           \
     }
 #define FILL_METADATA_STR(s, key)  FILL_METADATA(s, key, s->key)
 #define FILL_METADATA_INT(s, key) {                                           \