MediaConnection: Review format negotiation mechanism

headers/private/media/experimental/MediaClientDefs.h

@@ -67,8 +67,12 @@ typedef struct media_connection {
 	BMessage*					ToMessage() const;
 
 private:
-	media_input					_MediaInput() const;
-	media_output				_MediaOutput() const;
+	// NOTE: We are doing this on purpose to avoid redundancy we
+	// want to build the input/output on the fly. In pratice, the
+	// only thing that can change is the format which is kept updated
+	// to reflect the current status of this connection.
+	media_input					_BuildMediaInput() const;
+	media_output				_BuildMediaOutput() const;
 
 	const media_source&			_Source() const;
 	const media_destination&	_Destination() const;
@@ -84,6 +88,9 @@ private:
 
     media_source				source;
     media_destination			destination;
+
+    // This format always reflect the most updated format depending
+    // on the connection phase.
     media_format				format;
     char						name[B_MEDIA_NAME_LENGTH];
 

headers/private/media/experimental/MediaConnection.h

@@ -43,12 +43,6 @@ public:
 	// return media_connection::null otherwise.
 	media_connection				Endpoint();
 
-	// This allow to specify a format that will be used while
-	// connecting to another node.
-	void							SetAcceptedFormat(
-										const media_format& format);
-	const media_format&				AcceptedFormat() const;
-
 	// Represents the buffer size, implement it to return the buffer size
 	// you decided for this connection.
 	// TODO: Do we want this (and ChainSize) moved on the output side?
@@ -125,13 +119,14 @@ protected:
 	virtual							~BMediaInput();
 
 	// Callbacks
+	virtual status_t				AcceptFormat(media_format* format) = 0;
+
 	virtual void					HandleBuffer(BBuffer* buffer);
 
 	virtual void					Connected(const media_format& format);
 	virtual void					Disconnected();
 
 private:
-	media_input						_MediaInput() const;
 
 	virtual	void					_ReservedMediaInput0();
 	virtual	void					_ReservedMediaInput1();
@@ -156,8 +151,8 @@ protected:
 	virtual							~BMediaOutput();
 
 	// Callbacks
-	virtual status_t				PrepareToConnect(media_format* format);
-	virtual status_t				FormatProposal(media_format* format);
+	virtual status_t				PrepareToConnect(media_format* format) = 0;
+	virtual status_t				FormatProposal(media_format* format) = 0;
 
 	// When a connection is not binded with another, and you really don't want
 	// to use BMediaGraph it's your job to send the buffer to the connection
@@ -170,7 +165,6 @@ protected:
 	virtual void					Disconnected();
 
 private:
-	media_output					_MediaOutput() const;
 
 	// TODO: possibly unneeded.
 	void							_SetEnabled(bool enabled);

headers/private/media/experimental/SimpleMediaClient.h

@@ -117,6 +117,12 @@ public:
 	virtual size_t					BufferSize() const;
 	virtual void					SetBufferSize(size_t bufferSize);
 
+			// This allow to specify a format that will be used while
+			// connecting to another node.
+			void					SetAcceptedFormat(
+										const media_format& format);
+			const media_format&		AcceptedFormat() const;
+
 protected:
 									BSimpleMediaConnection(
 										media_connection_kinds kinds);
@@ -128,6 +134,8 @@ protected:
 			void*					fBufferCookie;
 
 			size_t					fBufferSize;
+
+			media_format			fAcceptedFormat;
 };
 
 
@@ -138,10 +146,12 @@ public:
 protected:
 	virtual							~BSimpleMediaInput();
 
-	virtual void					Connected(const media_format& format);
-	virtual void					Disconnected();
+	virtual status_t				AcceptFormat(media_format* format);
 
 	virtual void					HandleBuffer(BBuffer* buffer);
+
+	virtual void					Connected(const media_format& format);
+	virtual void					Disconnected();
 };
 
 
@@ -152,10 +162,11 @@ public:
 protected:
 	virtual							~BSimpleMediaOutput();
 
+	virtual status_t				PrepareToConnect(media_format* format);
+	virtual status_t				FormatProposal(media_format* format);
+
 	virtual void					Connected(const media_format& format);
 	virtual void					Disconnected();
-
-	virtual status_t				FormatProposal(media_format* format);
 };