media/video/video_decode_accelerator.h

   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:
  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_