Expose metadata found in onCuePoint events in .flv files.

Currently, only onMetaData is used, but some providers (wrongly)
put metadata into onCuePoint events, and it's still nice to be
able to use that data.

onCuePoint events also present metadata slightly differently than
onMetaData events: all metadata is found inside an object called
"parameters". In order to extract this metadata, it's easiest to
recurse through the object tree and pull out anything found in
child objects and put it in the top-level metadata.

Reference: http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/2/help.html?content=00001404.html

Signed-off-by: Anton Khirnov <anton@khirnov.net>

libavformat/flvdec.c

@@ -438,8 +438,9 @@ static int amf_parse_object(AVFormatContext *s, AVStream *astream,
         return -1;
     }
 
-    // only look for metadata values when we are not nested and key != NULL
-    if (depth == 1 && key) {
+    if (key) {
+        // stream info doesn't live any deeper than the first object
+        if (depth == 1) {
             acodec = astream ? astream->codec : NULL;
             vcodec = vstream ? vstream->codec : NULL;
 
@@ -480,6 +481,7 @@ static int amf_parse_object(AVFormatContext *s, AVStream *astream,
                     }
                 }
             }
+        }
 
         if (!strcmp(key, "duration")        ||
             !strcmp(key, "filesize")        ||
@@ -533,7 +535,7 @@ static int flv_read_metabody(AVFormatContext *s, int64_t next_pos)
     if (!strcmp(buffer, "onTextData"))
         return 1;
 
-    if (strcmp(buffer, "onMetaData"))
+    if (strcmp(buffer, "onMetaData") && strcmp(buffer, "onCuePoint"))
         return -1;
 
     // find the streams now so that amf_parse_object doesn't need to do