Add media::VideoEncodeAccelerator with WebRTC integration

media/video/video_encode_accelerator.h

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_VIDEO_VIDEO_ENCODE_ACCELERATOR_H_
+#define MEDIA_VIDEO_VIDEO_ENCODE_ACCELERATOR_H_
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
+#include "media/base/bitstream_buffer.h"
+#include "media/base/media_export.h"
+#include "media/base/video_decoder_config.h"
+#include "media/base/video_frame.h"
+
+namespace media {
+
+class BitstreamBuffer;
+class VideoFrame;
+
+// Video encoder interface.
+class MEDIA_EXPORT VideoEncodeAccelerator {
+ public:
+  virtual ~VideoEncodeAccelerator();
+
+  // Specification of an encoding profile supported by an encoder.
+  struct SupportedProfile {
+    VideoCodecProfile profile;
+    gfx::Size max_resolution;
+    struct {
+      uint32 numerator;
+      uint32 denominator;
+    } max_framerate;
+  };
+
+  // Enumeration of potential errors generated by the API.
+  enum Error {
+    // An operation was attempted during an incompatible encoder state.
+    kIllegalStateError,
+    // Invalid argument was passed to an API method.
+    kInvalidArgumentError,
+    // A failure occurred at the browser layer or one of its dependencies.
+    // Examples of such failures include GPU hardware failures, GPU driver
+    // failures, GPU library failures, browser programming errors, and so on.
+    kPlatformFailureError,
+  };
+
+  // Interface for clients that use VideoEncodeAccelerator.
+  class MEDIA_EXPORT Client {
+   public:
+    // Callback to notify client that encoder has been successfully initialized.
+    virtual void NotifyInitializeDone() = 0;
+
+    // Callback to tell the client what size of buffers to provide for input and
+    // output.  The VEA disclaims use or ownership of all previously provided
+    // buffers once this callback is made.
+    // Parameters:
+    //  |input_count| is the number of input frames required for encoding.  The
+    //  client should provide at least this many frames, since the encoder may
+    //  need to hold onto some subset of inputs as reference pictures.
+    //  |input_dimensions| are the logical dimensions of the input frames to
+    //  encode, in pixels.  The encoder may have hardware alignment requirements
+    //  that make this different from |input_resolution|, as requested in
+    //  Initialize(), in which case the input buffer should be padded to
+    //  |input_dimensions|.
+    //  |output_size| is the required size of output buffers for this encoder,
+    //  in bytes.
+    virtual void RequireBitstreamBuffers(int input_count,
+                                         const gfx::Size& input_dimensions,
+                                         size_t output_size) = 0;
+
+    // Callback to notify that encoder has finished with an input frame.
+    virtual void NotifyInputDone(int32 bitstream_buffer_id) = 0;
+
+    // Callback to deliver encoded bitstream buffers.  The VEA disclaims use or
+    // ownership of the specified buffer once this callback is made.
+    // |bitstream_buffer_id| is the id of the buffer that is ready.
+    // |size| is the byte size of the used portion of the buffer.
+    virtual void BitstreamBufferReady(int32 bitstream_buffer_id,
+                                      size_t payload_size,
+                                      bool key_frame) = 0;
+
+    // Error notification callback.
+    virtual void NotifyError(Error error) = 0;
+
+   protected:
+    virtual ~Client() {}
+  };
+
+  // Video encoder functions.
+
+  // Initialize the video encoder with a specific configuration.  Called once
+  // per encoder construction.
+  // Parameters:
+  //  |input_format| is the frame format of the input stream.
+  //  |input_resolution| is the resolution of the input stream.
+  //  |output_profile| is the codec profile of the encoded output stream.
+  //  |initial_bitrate| is the initial bitrate of the encoded output stream,
+  //  in bits per second.
+  virtual void Initialize(media::VideoFrame::Format input_format,
+                          const gfx::Size& input_resolution,
+                          VideoCodecProfile output_profile,
+                          int32 initial_bitrate) = 0;
+
+  // Encodes the given frame.
+  // Parameters:
+  //  |buffer| is the buffer holding the frame that is to be encoded (with a
+  //  buffer logical size/width as specified in RequireBitstreamBuffers(), and
+  //  visible size/width as specified in Initialize()).
+  //  |force_keyframe| forces the encoding of a keyframe for this frame.
+  virtual void Encode(const BitstreamBuffer& buffer, bool force_keyframe) = 0;
+
+  // Send a bitstream buffer to the encoder to be used for storing future
+  // encoded output.
+  // Parameters:
+  //  |buffer| is the bitstream buffer to use for output.
+  virtual void UseOutputBitstreamBuffer(const BitstreamBuffer& buffer) = 0;
+
+  // Request a change to the encoding parameters.  This is only a request,
+  // fulfilled on a best-effort basis.
+  // Parameters:
+  //  |bitrate| is the requested new bitrate, in bits per second.
+  virtual void RequestEncodingParameterChange(int32 bitrate) = 0;
+
+  // Destroys the encoder: all pending inputs are dropped immediately and the
+  // component is freed.  This call may asynchronously free system resources,
+  // but its client-visible effects are synchronous.  After this method returns
+  // no more callbacks will be made on the client.  Deletes |this|
+  // unconditionally, so make sure to drop all pointers to it!
+  virtual void Destroy() = 0;
+};
+
+}  // namespace media
+
+#endif  // MEDIA_VIDEO_VIDEO_ENCODE_ACCELERATOR_H_