video_decoder.h revision 68043e1e95eeb07d5cae7aca370b26518b0867d6 
1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef REMOTING_CODEC_VIDEO_DECODER_H_
6#define REMOTING_CODEC_VIDEO_DECODER_H_
7
8#include "base/basictypes.h"
9#include "remoting/proto/video.pb.h"
10
11namespace webrtc {
12class DesktopRect;
13class DesktopRegion;
14class DesktopSize;
15}  // namespace webrtc
16
17namespace remoting {
18
19// Interface for a decoder that takes a stream of bytes from the network and
20// outputs frames of data.
21class VideoDecoder {
22 public:
23  static const int kBytesPerPixel = 4;
24
25  VideoDecoder() {}
26  virtual ~VideoDecoder() {}
27
28  // Initializes the decoder and sets the output dimensions.
29  // |screen size| must not be empty.
30  virtual void Initialize(const webrtc::DesktopSize& screen_size) = 0;
31
32  // Feeds more data into the decoder. Returns true if |packet| was processed
33  // and the frame can be displayed now.
34  virtual bool DecodePacket(const VideoPacket& packet) = 0;
35
36  // Marks the specified |region| of the view for update the next time
37  // RenderFrame() is called.  |region| is expressed in |view_size| coordinates.
38  // |view_size| must not be empty.
39  virtual void Invalidate(const webrtc::DesktopSize& view_size,
40                          const webrtc::DesktopRegion& region) = 0;
41
42  // Copies invalidated pixels within |clip_area| to |image_buffer|. Pixels are
43  // invalidated either by new data received in DecodePacket(), or by explicit
44  // calls to Invalidate(). |clip_area| is specified in |view_size| coordinates.
45  // If |view_size| differs from the source size then the copied pixels will be
46  // scaled accordingly. |view_size| cannot be empty.
47  //
48  // |image_buffer|'s origin must correspond to the top-left of |clip_area|,
49  // and the buffer must be large enough to hold |clip_area| RGBA32 pixels.
50  // |image_stride| gives the output buffer's stride in pixels.
51  //
52  // On return, |output_region| contains the updated area, in |view_size|
53  // coordinates.
54  virtual void RenderFrame(const webrtc::DesktopSize& view_size,
55                           const webrtc::DesktopRect& clip_area,
56                           uint8* image_buffer,
57                           int image_stride,
58                           webrtc::DesktopRegion* output_region) = 0;
59
60  // Returns the "shape", if any, of the most recently rendered frame.
61  // The shape is returned in source dimensions.
62  virtual const webrtc::DesktopRegion* GetImageShape() = 0;
63};
64
65}  // namespace remoting
66
67#endif  // REMOTING_CODEC_VIDEO_DECODER_H_
68