video_decoder.h revision d0247b1b59f9c528cb6df88b4f2b9afaf80d181e 
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  // DecodeResult is returned from DecodePacket() and indicates current state
24  // of the decoder. DECODE_DONE means that last packet for the frame was
25  // processed, and the frame can be displayed now. DECODE_ERROR is returned if
26  // there was an error in the stream.
27  enum DecodeResult {
28    DECODE_ERROR,
29    DECODE_DONE,
30  };
31
32  VideoDecoder() {}
33  virtual ~VideoDecoder() {}
34
35  // Initializes the decoder and sets the output dimensions.
36  // |screen size| must not be empty.
37  virtual void Initialize(const webrtc::DesktopSize& screen_size) = 0;
38
39  // Feeds more data into the decoder.
40  virtual DecodeResult DecodePacket(const VideoPacket* packet) = 0;
41
42  // Returns true if decoder is ready to accept data via DecodePacket.
43  virtual bool IsReadyForData() = 0;
44
45  virtual VideoPacketFormat::Encoding Encoding() = 0;
46
47  // Marks the specified |region| of the view for update the next time
48  // RenderFrame() is called.  |region| is expressed in |view_size| coordinates.
49  // |view_size| must not be empty.
50  virtual void Invalidate(const webrtc::DesktopSize& view_size,
51                          const webrtc::DesktopRegion& region) = 0;
52
53  // Copies invalidated pixels within |clip_area| to |image_buffer|. Pixels are
54  // invalidated either by new data received in DecodePacket(), or by explicit
55  // calls to Invalidate(). |clip_area| is specified in |view_size| coordinates.
56  // If |view_size| differs from the source size then the copied pixels will be
57  // scaled accordingly. |view_size| cannot be empty.
58  //
59  // |image_buffer|'s origin must correspond to the top-left of |clip_area|,
60  // and the buffer must be large enough to hold |clip_area| RGBA32 pixels.
61  // |image_stride| gives the output buffer's stride in pixels.
62  //
63  // On return, |output_region| contains the updated area, in |view_size|
64  // coordinates.
65  virtual void RenderFrame(const webrtc::DesktopSize& view_size,
66                           const webrtc::DesktopRect& clip_area,
67                           uint8* image_buffer,
68                           int image_stride,
69                           webrtc::DesktopRegion* output_region) = 0;
70
71  // Returns the "shape", if any, of the most recently rendered frame.
72  // The shape is returned in source dimensions.
73  virtual const webrtc::DesktopRegion* GetImageShape() = 0;
74};
75
76}  // namespace remoting
77
78#endif  // REMOTING_CODEC_VIDEO_DECODER_H_
79