* A BBuffer does not know where it came from, so

BBufferConsumer::BufferReceived() cannot know whom to send the "buffer is
  late" notification (unless we only have a single input). To solve this, the
  media_header now contains extra fields that can be used to create a
  media_source object.
* Unfortunately, BBufferProducer::SendBuffer() cannot know the output either in
  case there is more than one. Hence, I deprecated the existing SendBuffer()
  call and moved it into "private" - IOW old sources using it won't compile
  anymore under Haiku.
* I introduced a new SendBuffer() variant that also gets the media_source as
  argument.
* Updated all sources (that are part of the image) to use the new variant.
* Removed some purposely commented out code in the audio mixer.
* Implemented late buffer notification, as well as late buffer handling in the
  audio mixer; this is a bit of work in progress, so the debug output is left
  in there.
* Some cleanup.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@36184 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/os/media/BufferProducer.h

@@ -138,6 +138,7 @@ protected:
 
 	// NOTE: Use this function to pass on the buffer on to the BBufferConsumer.
 			status_t			SendBuffer(BBuffer* buffer,
+									const media_source& source, 
 									const media_destination& destination);
 
 			status_t			SendDataStatus(int32 status,
@@ -205,6 +206,10 @@ private:
 	virtual	status_t			_Reserved_BufferProducer_14(void*);
 	virtual	status_t			_Reserved_BufferProducer_15(void*);
 
+	// deprecated calls
+			status_t			SendBuffer(BBuffer* buffer,
+									const media_destination& destination);
+
 private:
 			friend class BBufferConsumer;
 			friend class BMediaNode;

headers/os/media/MediaDefs.h

@@ -671,7 +671,8 @@ struct media_header {
 	};
 	type_code		user_data_type;
 	uchar			user_data[64];	// user_data_type indicates what this is
-	uint32			_reserved_[2];
+	int32			source;
+	port_id			source_port;
 
 	off_t			file_pos;		// where in a file this data came from
 	size_t			orig_size;		// and how big it was.  if unused, zero out