lavc: add profiles to AVCodecDescriptor

The profiles are a property of the codec, so it makes sense to export
them through AVCodecDescriptors, not just the codec implementations.

libavcodec/utils.c

@@ -1918,6 +1918,21 @@ const char *av_get_profile_name(const AVCodec *codec, int profile)
     return NULL;
 }
 
+const char *avcodec_profile_name(enum AVCodecID codec_id, int profile)
+{
+    const AVCodecDescriptor *desc = avcodec_descriptor_get(codec_id);
+    const AVProfile *p;
+
+    if (profile == FF_PROFILE_UNKNOWN || !desc || !desc->profiles)
+        return NULL;
+
+    for (p = desc->profiles; p->profile != FF_PROFILE_UNKNOWN; p++)
+        if (p->profile == profile)
+            return p->name;
+
+    return NULL;
+}
+
 unsigned avcodec_version(void)
 {
     return LIBAVCODEC_VERSION_INT;