media/video/video_encode_accelerator.h

   1 // Copyright 2013 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_ENCODE_ACCELERATOR_H_
   6 #define MEDIA_VIDEO_VIDEO_ENCODE_ACCELERATOR_H_
   7
   8 #include <vector>
   9
  10 #include "base/basictypes.h"
  11 #include "base/memory/ref_counted.h"
  12 #include "media/base/bitstream_buffer.h"
  13 #include "media/base/media_export.h"
  14 #include "media/base/video_decoder_config.h"
  15 #include "media/base/video_frame.h"
  16
  17 namespace media {
  18
  19 class BitstreamBuffer;
  20 class VideoFrame;
  21
  22 // Video encoder interface.
  23 class MEDIA_EXPORT VideoEncodeAccelerator {
  24  public:
  25   // Specification of an encoding profile supported by an encoder.
  26   struct SupportedProfile {
  27     VideoCodecProfile profile;
  28     gfx::Size max_resolution;
  29     struct {
  30       uint32 numerator;
  31       uint32 denominator;
  32     } max_framerate;
  33   };
  34
  35   // Enumeration of potential errors generated by the API.
  36   enum Error {
  37     // An operation was attempted during an incompatible encoder state.
  38     kIllegalStateError,
  39     // Invalid argument was passed to an API method.
  40     kInvalidArgumentError,
  41     // A failure occurred at the GPU process or one of its dependencies.
  42     // Examples of such failures include GPU hardware failures, GPU driver
  43     // failures, GPU library failures, GPU process programming errors, and so
  44     // on.
  45     kPlatformFailureError,
  46     kErrorMax = kPlatformFailureError
  47   };
  48
  49   // Interface for clients that use VideoEncodeAccelerator. These callbacks will
  50   // not be made unless Initialize() has returned successfully.
  51   class MEDIA_EXPORT Client {
  52    public:
  53     // Callback to tell the client what size of frames and buffers to provide
  54     // for input and output.  The VEA disclaims use or ownership of all
  55     // previously provided buffers once this callback is made.
  56     // Parameters:
  57     //  |input_count| is the number of input VideoFrames required for encoding.
  58     //  The client should be prepared to feed at least this many frames into the
  59     //  encoder before being returned any input frames, since the encoder may
  60     //  need to hold onto some subset of inputs as reference pictures.
  61     //  |input_coded_size| is the logical size of the input frames (as reported
  62     //  by VideoFrame::coded_size()) to encode, in pixels.  The encoder may have
  63     //  hardware alignment requirements that make this different from
  64     //  |input_visible_size|, as requested in Initialize(), in which case the
  65     //  input VideoFrame to Encode() should be padded appropriately.
  66     //  |output_buffer_size| is the required size of output buffers for this
  67     //  encoder in bytes.
  68     virtual void RequireBitstreamBuffers(unsigned int input_count,
  69                                          const gfx::Size& input_coded_size,
  70                                          size_t output_buffer_size) = 0;
  71
  72     // Callback to deliver encoded bitstream buffers.  Ownership of the buffer
  73     // is transferred back to the VEA::Client once this callback is made.
  74     // Parameters:
  75     //  |bitstream_buffer_id| is the id of the buffer that is ready.
  76     //  |payload_size| is the byte size of the used portion of the buffer.
  77     //  |key_frame| is true if this delivered frame is a keyframe.
  78     virtual void BitstreamBufferReady(int32 bitstream_buffer_id,
  79                                       size_t payload_size,
  80                                       bool key_frame) = 0;
  81
  82     // Error notification callback. Note that errors in Initialize() will not be
  83     // reported here, but will instead be indicated by a false return value
  84     // there.
  85     virtual void NotifyError(Error error) = 0;
  86
  87    protected:
  88     // Clients are not owned by VEA instances and should not be deleted through
  89     // these pointers.
  90     virtual ~Client() {}
  91   };
  92
  93   // Video encoder functions.
  94
  95   // Initializes the video encoder with specific configuration.  Called once per
  96   // encoder construction.  This call is synchronous and returns true iff
  97   // initialization is successful.
  98   // Parameters:
  99   //  |input_format| is the frame format of the input stream (as would be
 100   //  reported by VideoFrame::format() for frames passed to Encode()).
 101   //  |input_visible_size| is the resolution of the input stream (as would be
 102   //  reported by VideoFrame::visible_rect().size() for frames passed to
 103   //  Encode()).
 104   //  |output_profile| is the codec profile of the encoded output stream.
 105   //  |initial_bitrate| is the initial bitrate of the encoded output stream,
 106   //  in bits per second.
 107   //  |client| is the client of this video encoder.  The provided pointer must
 108   //  be valid until Destroy() is called.
 109   // TODO(sheu): handle resolution changes.  http://crbug.com/249944
 110   virtual bool Initialize(VideoFrame::Format input_format,
 111                           const gfx::Size& input_visible_size,
 112                           VideoCodecProfile output_profile,
 113                           uint32 initial_bitrate,
 114                           Client* client) = 0;
 115
 116   // Encodes the given frame.
 117   // Parameters:
 118   //  |frame| is the VideoFrame that is to be encoded.
 119   //  |force_keyframe| forces the encoding of a keyframe for this frame.
 120   virtual void Encode(const scoped_refptr<VideoFrame>& frame,
 121                       bool force_keyframe) = 0;
 122
 123   // Send a bitstream buffer to the encoder to be used for storing future
 124   // encoded output.  Each call here with a given |buffer| will cause the buffer
 125   // to be filled once, then returned with BitstreamBufferReady().
 126   // Parameters:
 127   //  |buffer| is the bitstream buffer to use for output.
 128   virtual void UseOutputBitstreamBuffer(const BitstreamBuffer& buffer) = 0;
 129
 130   // Request a change to the encoding parameters.  This is only a request,
 131   // fulfilled on a best-effort basis.
 132   // Parameters:
 133   //  |bitrate| is the requested new bitrate, in bits per second.
 134   //  |framerate| is the requested new framerate, in frames per second.
 135   virtual void RequestEncodingParametersChange(uint32 bitrate,
 136                                                uint32 framerate) = 0;
 137
 138   // Destroys the encoder: all pending inputs and outputs are dropped
 139   // immediately and the component is freed.  This call may asynchronously free
 140   // system resources, but its client-visible effects are synchronous.  After
 141   // this method returns no more callbacks will be made on the client.  Deletes
 142   // |this| unconditionally, so make sure to drop all pointers to it!
 143   virtual void Destroy() = 0;
 144
 145  protected:
 146   // Do not delete directly; use Destroy() or own it with a scoped_ptr, which
 147   // will Destroy() it properly by default.
 148   virtual ~VideoEncodeAccelerator();
 149 };
 150
 151 }  // namespace media
 152
 153 namespace base {
 154
 155 template <class T>
 156 struct DefaultDeleter;
 157
 158 // Specialize DefaultDeleter so that scoped_ptr<VideoEncodeAccelerator> always
 159 // uses "Destroy()" instead of trying to use the destructor.
 160 template <>
 161 struct MEDIA_EXPORT DefaultDeleter<media::VideoEncodeAccelerator> {
 162  public:
 163   void operator()(void* video_encode_accelerator) const;
 164 };
 165
 166 }  // namespace base
 167
 168 #endif  // MEDIA_VIDEO_VIDEO_ENCODE_ACCELERATOR_H_