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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 MEDIA_VIDEO_VIDEO_DECODE_ACCELERATOR_H_
6 #define MEDIA_VIDEO_VIDEO_DECODE_ACCELERATOR_H_
7 
8 #include <vector>
9 
10 #include "base/basictypes.h"
11 #include "media/base/bitstream_buffer.h"
12 #include "media/base/video_decoder_config.h"
13 #include "media/video/picture.h"
14 #include "ui/gfx/size.h"
15 
16 namespace media {
17 
18 // Video decoder interface.
19 // This interface is extended by the various components that ultimately
20 // implement the backend of PPB_VideoDecode_Dev.
21 class MEDIA_EXPORT VideoDecodeAccelerator {
22  public:
23   // Enumeration of potential errors generated by the API.
24   // Note: Keep these in sync with PP_VideoDecodeError_Dev. Also do not
25   // rearrange, reuse or remove values as they are used for gathering UMA
26   // statistics.
27   enum Error {
28     // An operation was attempted during an incompatible decoder state.
29     ILLEGAL_STATE = 1,
30     // Invalid argument was passed to an API method.
31     INVALID_ARGUMENT,
32     // Encoded input is unreadable.
33     UNREADABLE_INPUT,
34     // A failure occurred at the browser layer or one of its dependencies.
35     // Examples of such failures include GPU hardware failures, GPU driver
36     // failures, GPU library failures, browser programming errors, and so on.
37     PLATFORM_FAILURE,
38     // Largest used enum. This should be adjusted when new errors are added.
39     LARGEST_ERROR_ENUM,
40   };
41 
42   // Interface for collaborating with picture interface to provide memory for
43   // output picture and blitting them. These callbacks will not be made unless
44   // Initialize() has returned successfully.
45   // This interface is extended by the various layers that relay messages back
46   // to the plugin, through the PPP_VideoDecode_Dev interface the plugin
47   // implements.
48   class MEDIA_EXPORT Client {
49    public:
50     // Callback to tell client how many and what size of buffers to provide.
51     virtual void ProvidePictureBuffers(uint32 requested_num_of_buffers,
52                                        const gfx::Size& dimensions,
53                                        uint32 texture_target) = 0;
54 
55     // Callback to dismiss picture buffer that was assigned earlier.
56     virtual void DismissPictureBuffer(int32 picture_buffer_id) = 0;
57 
58     // Callback to deliver decoded pictures ready to be displayed.
59     virtual void PictureReady(const Picture& picture) = 0;
60 
61     // Callback to notify that decoded has decoded the end of the current
62     // bitstream buffer.
63     virtual void NotifyEndOfBitstreamBuffer(int32 bitstream_buffer_id) = 0;
64 
65     // Flush completion callback.
66     virtual void NotifyFlushDone() = 0;
67 
68     // Reset completion callback.
69     virtual void NotifyResetDone() = 0;
70 
71     // Callback to notify about decoding errors. Note that errors in
72     // Initialize() will not be reported here, but will instead be indicated by
73     // a false return value there.
74     virtual void NotifyError(Error error) = 0;
75 
76    protected:
~Client()77     virtual ~Client() {}
78   };
79 
80   // Video decoder functions.
81 
82   // Initializes the video decoder with specific configuration.  Called once per
83   // decoder construction.  This call is synchronous and returns true iff
84   // initialization is successful.
85   // Parameters:
86   //  |profile| is the video stream's format profile.
87   //  |client| is the client of this video decoder.  The provided pointer must
88   //  be valid until Destroy() is called.
89   virtual bool Initialize(VideoCodecProfile profile, Client* client) = 0;
90 
91   // Decodes given bitstream buffer that contains at most one frame.  Once
92   // decoder is done with processing |bitstream_buffer| it will call
93   // NotifyEndOfBitstreamBuffer() with the bitstream buffer id.
94   // Parameters:
95   //  |bitstream_buffer| is the input bitstream that is sent for decoding.
96   virtual void Decode(const BitstreamBuffer& bitstream_buffer) = 0;
97 
98   // Assigns a set of texture-backed picture buffers to the video decoder.
99   //
100   // Ownership of each picture buffer remains with the client, but the client
101   // is not allowed to deallocate the buffer before the DismissPictureBuffer
102   // callback has been initiated for a given buffer.
103   //
104   // Parameters:
105   //  |buffers| contains the allocated picture buffers for the output.
106   virtual void AssignPictureBuffers(
107       const std::vector<PictureBuffer>& buffers) = 0;
108 
109   // Sends picture buffers to be reused by the decoder. This needs to be called
110   // for each buffer that has been processed so that decoder may know onto which
111   // picture buffers it can write the output to.
112   //
113   // Parameters:
114   //  |picture_buffer_id| id of the picture buffer that is to be reused.
115   virtual void ReusePictureBuffer(int32 picture_buffer_id) = 0;
116 
117   // Flushes the decoder: all pending inputs will be decoded and pictures handed
118   // back to the client, followed by NotifyFlushDone() being called on the
119   // client.  Can be used to implement "end of stream" notification.
120   virtual void Flush() = 0;
121 
122   // Resets the decoder: all pending inputs are dropped immediately and the
123   // decoder returned to a state ready for further Decode()s, followed by
124   // NotifyResetDone() being called on the client.  Can be used to implement
125   // "seek".
126   virtual void Reset() = 0;
127 
128   // Destroys the decoder: all pending inputs are dropped immediately and the
129   // component is freed.  This call may asynchornously free system resources,
130   // but its client-visible effects are synchronous.  After this method returns
131   // no more callbacks will be made on the client.  Deletes |this|
132   // unconditionally, so make sure to drop all pointers to it!
133   virtual void Destroy() = 0;
134 
135   // GPU PROCESS ONLY.  Implementations of this interface in the
136   // content/common/gpu/media should implement this, and implementations in
137   // other processes should not override the default implementation.
138   // Returns true if VDA::Decode and VDA::Client callbacks can run on the IO
139   // thread. Otherwise they will run on the GPU child thread. The purpose of
140   // running Decode on the IO thread is to reduce decode latency. Note Decode
141   // should return as soon as possible and not block on the IO thread. Also,
142   // PictureReady should be run on the child thread if a picture is delivered
143   // the first time so it can be cleared.
144   virtual bool CanDecodeOnIOThread();
145 
146  protected:
147   // Do not delete directly; use Destroy() or own it with a scoped_ptr, which
148   // will Destroy() it properly by default.
149   virtual ~VideoDecodeAccelerator();
150 };
151 
152 }  // namespace media
153 
154 namespace base {
155 
156 template <class T>
157 struct DefaultDeleter;
158 
159 // Specialize DefaultDeleter so that scoped_ptr<VideoDecodeAccelerator> always
160 // uses "Destroy()" instead of trying to use the destructor.
161 template <>
162 struct MEDIA_EXPORT DefaultDeleter<media::VideoDecodeAccelerator> {
163  public:
164   void operator()(void* video_decode_accelerator) const;
165 };
166 
167 }  // namespace base
168 
169 #endif  // MEDIA_VIDEO_VIDEO_DECODE_ACCELERATOR_H_
170