audioconvert: add av_get_channel_description().

libavutil/audioconvert.c

@@ -219,6 +219,17 @@ const char *av_get_channel_name(uint64_t channel)
     return NULL;
 }
 
+const char *av_get_channel_description(uint64_t channel)
+{
+    int i;
+    if (av_get_channel_layout_nb_channels(channel) != 1)
+        return NULL;
+    for (i = 0; i < FF_ARRAY_ELEMS(channel_names); i++)
+        if ((1ULL<<i) & channel)
+            return channel_names[i].description;
+    return NULL;
+}
+
 uint64_t av_channel_layout_extract_channel(uint64_t channel_layout, int index)
 {
     int i;

libavutil/audioconvert.h

@@ -180,6 +180,14 @@ uint64_t av_channel_layout_extract_channel(uint64_t channel_layout, int index);
  */
 const char *av_get_channel_name(uint64_t channel);
 
+/**
+ * Get the description of a given channel.
+ *
+ * @param channel  a channel layout with a single channel
+ * @return  channel description on success, NULL on error
+ */
+const char *av_get_channel_description(uint64_t channel);
+
 /**
  * @}
  */