Remove media::VideoFrame from media::VideoCaptureDevice::Client interface

media/video/capture/video_capture_device.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // VideoCaptureDevice is the abstract base class for realizing video capture
 // device support in Chromium. It provides the interface for OS dependent
 // implementations.
 // The class is created and functions are invoked on a thread owned by
 // VideoCaptureManager. Capturing is done on other threads, depending on the OS
 // specific implementation.
@@ skipping 102 matching lines @@
       : public NON_EXPORTED_BASE(std::list<Name>) {
    public:
     // Returns NULL if no entry was found by that ID.
     Name* FindById(const std::string& id);
 
     // Allow generated copy constructor and assignment.
   };
 
   class MEDIA_EXPORT Client {
    public:
+    // Memory buffer returned by Client::ReserveOutputBuffer().
+    class Buffer {
+     public:
+      Buffer(void* data, size_t size) : data_(data), size_(size) {}

[ncarter (slow), 2013/10/29 18:42:17]

Do you expect Buffer to be created directly? If this type is designed for
inheritance, should the ctor be protected?

[sheu, 2013/11/05 20:02:10]

Done.

+      virtual ~Buffer() {}
+
+      void* data() const { return data_; }
+      size_t size() const { return size_; }
+
+     private:
+      void* const data_;
+      const size_t size_;
+    };
+
     virtual ~Client() {}
 
-    // Reserve an output buffer into which a video frame can be captured
-    // directly. If all buffers are currently busy, returns NULL.
+    // Reserve an output buffer into which contents can be captured directly.
+    // The returned Buffer will always be allocated with a memory size suitable
+    // for holding a packed video frame of |format| format, of |dimensions|
+    // dimensions. It is permissible for |dimensions| to be zero; in which
+    // case the returned Buffer does not guarantee memory backing, but functions
+    // as a reservation for external input for the purposes of buffer
+    // throttling.
     //
-    // The returned VideoFrames will always be allocated with a YV12 format and
-    // have dimensions matching |size|. It is the VideoCaptureDevice's
-    // responsibility to obey whatever stride and memory layout are indicated on
-    // the returned VideoFrame object.
-    //
-    // The output buffer stays reserved for use by the calling
-    // VideoCaptureDevice until either the last reference to the VideoFrame is
-    // released, or until the buffer is passed back to the Client's
-    // OnIncomingCapturedFrame() method.
-    virtual scoped_refptr<media::VideoFrame> ReserveOutputBuffer(
-        const gfx::Size& size) = 0;
+    // The output buffer stays reserved for use until the Buffer object is
+    // destroyed, or it is passed back to the Client's
+    // OnIncomingCaptured*Buffer() function.
+    virtual scoped_ptr<Buffer> ReserveOutputBuffer(
+        media::VideoFrame::Format format,
+        const gfx::Size& dimensions) = 0;
 
     // Captured a new video frame as a raw buffer. The size, color format, and
     // layout are taken from the parameters specified by an earlier call to
     // OnFrameInfo(). |data| must be packed, with no padding between rows and/or
     // color planes.
     //
     // This method will try to reserve an output buffer and copy from |data|
     // into the output buffer. If no output buffer is available, the frame will
     // be silently dropped.
     virtual void OnIncomingCapturedFrame(const uint8* data,
                                          int length,
                                          base::Time timestamp,
                                          int rotation,  // Clockwise.
                                          bool flip_vert,
                                          bool flip_horiz) = 0;
 
-    // Captured a new video frame, held in a VideoFrame container.
+    // Captured a new video frame, in a raw buffer backed by |buffer|.

[ncarter (slow), 2013/10/29 18:42:17]

"in a raw buffer backed by |buffer|" -> "held in |buffer|" or some such. ('raw'
not seeming to provide much distinguishing power here)

[sheu, 2013/11/05 20:02:10]

Done.

     //
-    // If |frame| was created via the ReserveOutputBuffer() mechanism, then the
-    // frame delivery is guaranteed (it will not be silently dropped), and
-    // delivery will require no additional copies in the browser process. For
-    // such frames, the VideoCaptureDevice's reservation on the output buffer
-    // ends immediately. The VideoCaptureDevice may not read or write the
-    // underlying memory afterwards, and it should release its references to
-    // |frame| as soon as possible, to allow buffer reuse.
-    //
-    // If |frame| was NOT created via ReserveOutputBuffer(), then this method
-    // will try to reserve an output buffer and copy from |frame| into the
-    // output buffer. If no output buffer is available, the frame will be
-    // silently dropped. |frame| must be allocated as RGB32, YV12 or I420, and
-    // the size must match that specified by an earlier call to OnFrameInfo().
-    virtual void OnIncomingCapturedVideoFrame(
-        const scoped_refptr<media::VideoFrame>& frame,
-        base::Time timestamp) = 0;
+    // As the frame is backed by a reservation returned by
+    // ReserveOutputBuffer(), delivery is guaranteed and will require no
+    // additional copies in the browser process. The caller gives up ownership
+    // of |buffer| and should not retained any cached pointers to its underlying
+    // memory.  |dimensions| indicates the frame width and height of the buffer
+    // contents; this is assumed to be of |format| format and tightly packed.
+    virtual void OnIncomingCapturedBuffer(scoped_ptr<Buffer> buffer,
+                                          media::VideoFrame::Format format,
+                                          const gfx::Size& dimensions,
+                                          base::Time timestamp) = 0;
 
     // An error has occurred that cannot be handled and VideoCaptureDevice must
     // be StopAndDeAllocate()-ed.
     virtual void OnError() = 0;
 
     // Called when VideoCaptureDevice::AllocateAndStart() has been called to
     // inform of the resulting frame size.
     virtual void OnFrameInfo(const VideoCaptureCapability& info) = 0;
 
     // Called when the native resolution of VideoCaptureDevice has been changed
@@ skipping 33 matching lines @@
   // If deallocation is done asynchronously, then the device implementation must
   // ensure that a subsequent AllocateAndStart() operation targeting the same ID
   // would be sequenced through the same task runner, so that deallocation
   // happens first.
   virtual void StopAndDeAllocate() = 0;
 };
 
 }  // namespace media
 
 #endif  // MEDIA_VIDEO_CAPTURE_VIDEO_CAPTURE_DEVICE_H_