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1 // Copyright (c) 2010 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2010 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef REMOTING_BASE_DECODER_H_ | 5 #ifndef REMOTING_BASE_DECODER_H_ |
6 #define REMOTING_BASE_DECODER_H_ | 6 #define REMOTING_BASE_DECODER_H_ |
7 | 7 |
8 #include <vector> | |
9 | |
10 #include "base/task.h" | 8 #include "base/task.h" |
11 #include "base/scoped_ptr.h" | 9 #include "base/scoped_ptr.h" |
12 #include "gfx/rect.h" | 10 #include "gfx/rect.h" |
13 #include "media/base/video_frame.h" | 11 #include "media/base/video_frame.h" |
14 #include "remoting/base/protocol/chromotocol.pb.h" | 12 #include "remoting/base/protocol/chromotocol.pb.h" |
15 | 13 |
16 namespace remoting { | 14 namespace remoting { |
17 | 15 |
18 // TODO(hclam): Merge this with the one in remoting/host/encoder.h. | |
19 typedef std::vector<gfx::Rect> UpdatedRects; | 16 typedef std::vector<gfx::Rect> UpdatedRects; |
20 | 17 |
21 // Defines the behavior of a decoder for decoding images received from the | 18 // Interface for a decoder that takes a stream of bytes from the network and |
22 // host. | 19 // outputs frames of data. |
23 // | 20 // |
24 // Sequence of actions with a decoder is as follows: | 21 // TODO(ajwong): Beef up this documentation once the API stablizes. |
25 // | |
26 // 1. BeginDecode(PartialDecodeDone, DecodeDone, VideoFrame) | |
27 // 2. PartialDecode(ChromotingHostMessage) | |
28 // ... | |
29 // 3. EndDecode() | |
30 // | |
31 // The decoder will reply with: | |
32 // 1. PartialDecodeDone(VideoFrame, UpdatedRects) | |
33 // ... | |
34 // 2. DecodeDone(VideoFrame) | |
35 // | |
36 // The format of VideoFrame is a contract between the object that creates the | |
37 // decoder (most likely the renderer) and the decoder. | |
38 class Decoder { | 22 class Decoder { |
39 public: | 23 public: |
40 Decoder() | 24 Decoder() {} |
41 : encoding_(EncodingInvalid), | 25 virtual ~Decoder() {} |
42 started_(false) { | |
43 } | |
44 virtual ~Decoder() { | |
45 } | |
46 | 26 |
47 // Tell the decoder to use |frame| as a target to write the decoded image | |
48 // for the coming update stream. | |
49 // If decode is partially done and |frame| can be read, |partial_decode_done| | |
50 // is called and |update_rects| contains the updated regions. | |
51 // If decode is completed |decode_done| is called. | |
52 // Return true if the decoder can writes output to |frame| and accept | |
53 // the codec format. | |
54 // TODO(hclam): Provide more information when calling this function. | |
55 virtual bool BeginDecode(scoped_refptr<media::VideoFrame> frame, | |
56 UpdatedRects* updated_rects, | |
57 Task* partial_decode_done, | |
58 Task* decode_done) = 0; | |
59 | |
60 // Give a ChromotingHostMessage that contains the update stream packet that | |
61 // contains the encoded data to the decoder. | |
62 // The decoder will own |message| and is responsible for deleting it. | |
63 // | |
64 // If the decoder has written something into |frame|, | |
65 // |partial_decode_done_| is called with |frame| and updated regions. | |
66 // Return true if the decoder can accept |message| and decode it. | |
67 // | |
68 // ChromotingHostMessage returned by this method will contain a | |
69 // UpdateStreamPacketMessage. | |
70 // This message will contain either: | |
71 // 1. UpdateStreamBeginRect | |
72 // 2. UpdateStreamRectData | |
73 // 3. UpdateStreamEndRect | |
74 // | |
75 // See remoting/base/protocol/chromotocol.proto for more information about | |
76 // these messages. | |
77 virtual bool PartialDecode(ChromotingHostMessage* message) = 0; | |
78 | |
79 // Notify the decoder that we have received the last update stream packet. | |
80 // If the decoding of the update stream has completed |decode_done_| is | |
81 // called with |frame|. | |
82 // If the update stream is not received fully and this method is called the | |
83 // decoder should also call |decode_done_| as soon as possible. | |
84 virtual void EndDecode() = 0; | |
85 | |
86 // Return the encoding type that this decoder handles. | |
87 virtual UpdateStreamEncoding Encoding() { return encoding_; } | |
88 | |
89 // Return the current state of the decoder: 'true' if we're in the middle | |
90 // of BeginDecode() / EndDecode(). | |
91 virtual bool IsStarted() { return started_; } | |
92 | |
93 // --- NEW API --- | |
94 // TODO(ajwong): This API is incorrect in the face of a streaming decode | 27 // TODO(ajwong): This API is incorrect in the face of a streaming decode |
95 // protocol like VP8. However, it breaks the layering abstraction by | 28 // protocol like VP8. However, it breaks the layering abstraction by |
96 // depending on the network packet protocol buffer type. I'm going to go | 29 // depending on the network packet protocol buffer type. I'm going to go |
97 // forward with it as is, and then refactor again to support streaming | 30 // forward with it as is, and then refactor again to support streaming |
98 // decodes. | 31 // decodes. |
99 | 32 |
100 // Initializes the decoder to draw into the given |frame|. The |clip| | 33 // Initializes the decoder to draw into the given |frame|. The |clip| |
101 // specifies the region to draw into. The clip region must fit inside | 34 // specifies the region to draw into. The clip region must fit inside |
102 // the dimensions of frame. Failure to do so will CHECK Fail. | 35 // the dimensions of frame. Failure to do so will CHECK Fail. |
| 36 // |
| 37 // TODO(ajwong): Should this take the source pixel format? |
| 38 // TODO(ajwong): Should the protocol be split into basic-types followed |
| 39 // by packet types? Basic types might include the format enum below. |
103 virtual void Initialize(scoped_refptr<media::VideoFrame> frame, | 40 virtual void Initialize(scoped_refptr<media::VideoFrame> frame, |
104 const gfx::Rect& clip) {} | 41 const gfx::Rect& clip, int bytes_per_src_pixel) = 0; |
105 | 42 |
106 // Reset the decoder to an uninitialized state. Release all references to | 43 // Reset the decoder to an uninitialized state. Release all references to |
107 // the initialized |frame|. Initialize() must be called before the decoder | 44 // the initialized |frame|. Initialize() must be called before the decoder |
108 // is used again. | 45 // is used again. |
109 virtual void Reset() {} | 46 virtual void Reset() = 0; |
110 | 47 |
111 // Feeds more data into the decoder. | 48 // Feeds more data into the decoder. |
112 virtual void DecodeBytes(const std::string& encoded_bytes) {} | 49 virtual void DecodeBytes(const std::string& encoded_bytes) = 0; |
113 | 50 |
114 // Returns true if decoder is ready to accept data via ProcessRectangleData. | 51 // Returns true if decoder is ready to accept data via ProcessRectangleData. |
115 virtual bool IsReadyForData() { return false; } | 52 virtual bool IsReadyForData() = 0; |
116 | 53 |
117 protected: | 54 virtual UpdateStreamEncoding Encoding() = 0; |
118 // Every decoder will have two internal states because there are three | |
119 // kinds of messages send to PartialDecode(). | |
120 // | |
121 // Here's a state diagram: | |
122 // | |
123 // UpdateStreamBeginRect UpdateStreamRectData | |
124 // .............. ............ | |
125 // . . . . | |
126 // . v . . | |
127 // kWaitingForBeginRect kWaitingForRectData . | |
128 // ^ . ^ . | |
129 // . . . . | |
130 // .............. ............ | |
131 // UpdateStreaEndRect | |
132 enum State { | |
133 // In this state the decoder is waiting for UpdateStreamBeginRect. | |
134 // After receiving UpdateStreaBeginRect, the encoder will transit to | |
135 // to kWaitingForRectData state. | |
136 kWaitingForBeginRect, | |
137 | |
138 // In this state the decoder is waiting for UpdateStreamRectData. | |
139 // The decode remains in this state if UpdateStreamRectData is received. | |
140 // The decoder will transit to kWaitingForBeginRect if UpdateStreamEndRect | |
141 // is received. | |
142 kWaitingForRectData, | |
143 }; | |
144 | |
145 // The encoding that this decoder supports. | |
146 UpdateStreamEncoding encoding_; | |
147 | |
148 // Has the decoder been started? I.e., has BeginDecode() been called. | |
149 bool started_; | |
150 }; | 55 }; |
151 | 56 |
152 } // namespace remoting | 57 } // namespace remoting |
153 | 58 |
154 #endif // REMOTING_BASE_DECODER_H_ | 59 #endif // REMOTING_BASE_DECODER_H_ |
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