Add ArcGpuVideoDecodeAccelerator.

chrome/gpu/arc_video_accelerator.h

+// Copyright 2016 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 CHROME_GPU_ARC_VIDEO_ACCELERATOR_H_
+#define CHROME_GPU_ARC_VIDEO_ACCELERATOR_H_
+
+namespace chromeos {
+namespace arc {
+
+enum HalPixelFormatExtension {
+  HAL_PIXEL_FORMAT_H264 = 0x34363248,
+  HAL_PIXEL_FORMAT_VP8 = 0x00385056,
+};
+
+enum PortType {
+  PORT_INPUT = 0,
+  PORT_OUTPUT = 1,
+  PORT_COUNT = 2,
+};
+
+enum BufferFlag {
+  BUFFER_FLAG_EOS = 1,

[Pawel Osciak, 2016/03/22 08:36:11]

Perhaps 1 << 0 to further emphasize these to be bitfield values (e.g. like
https://code.google.com/p/chromium/codesearch#chromium/src/base/files/file.h&...)

[Owen Lin, 2016/03/24 03:01:11]

Done.

+};
+
+struct BufferMetadata {
+  int64_t timestamp = 0;  // in microseconds
+  uint32_t flags = 0;

[Pawel Osciak, 2016/03/22 08:36:11]

Please add a comment this should use values from BufferFlag.

[Owen Lin, 2016/03/24 03:01:10]

Done.

+  uint32_t bytes_used = 0;
+};
+
+struct VideoFormat {
+  uint32_t pixel_format = 0;
+  uint32_t buffer_size = 0;
+
+  // minimal number of buffers required to process the video.

[Pawel Osciak, 2016/03/22 08:36:11]

s/minimal/Minimum/
s/process the video/decode\/encode the stream/

[Owen Lin, 2016/03/24 03:01:10]

Done.

+  uint32_t min_num_buffers = 0;
+  uint32_t coded_width = 0;
+  uint32_t coded_height = 0;
+  uint32_t crop_left = 0;
+  uint32_t crop_width = 0;
+  uint32_t crop_top = 0;
+  uint32_t crop_height = 0;
+};
+
+// ArcVideoAccelerator is a component of ArcCodec to deal with video
+// buffers. It is also an IPC interface between Android and Chromium.
+// So that the video buffers are sent to Chromium side and decoded.
+// ArcCodec implements ArcVideoAccelerator::Client and is responsible for

[Pawel Osciak, 2016/03/22 08:36:11]

Please remove or rephrase this sentence so that it applies to
ArcVideoAccelerator.

[Owen Lin, 2016/03/24 03:01:10]

Done.

+// rendering and interacting with the Android media framework.
+class ArcVideoAccelerator {
+ public:
+  enum Error {
+    ILLEGAL_STATE = 1,
+    INVALID_ARGUMENT = 2,
+    UNREADABLE_INPUT = 3,
+    PLATFORM_FAILURE = 4,
+  };
+
+  struct Config {
+    enum DeviceType {
+      DEVICE_ENCODER = 0,
+      DEVICE_DECODER = 1,
+    };
+
+    DeviceType device_type = DEVICE_DECODER;
+    size_t num_input_buffers = 0;
+    uint32_t input_pixel_format = 0;
+    // TODO: Add output_pixel_format. For now only the native pixel format

[Pawel Osciak, 2016/03/22 08:36:11]

TODO(owner):

[Owen Lin, 2016/03/24 03:01:10]

Done.

+    //       of each VDA on Chromium is supported.
+  };
+
+  // The callbacks of the ArcVideoAccelerator. ArcCodec implmenets this

[Pawel Osciak, 2016/03/22 08:36:11]

Please update the last sentence.

[Owen Lin, 2016/03/24 03:01:10]

Done.

+  // interface.
+  class Client {
+   public:
+    virtual ~Client() {}
+
+    // Called when an asynchronous error happens. Asynchronous errors happen
+    // only when the accelerator processes the input buffer and tried to

[Pawel Osciak, 2016/03/22 08:36:10]

Is this still applicable? I think we may OnError() in other situations?

[Owen Lin, 2016/03/24 03:01:10]

Indeed. Remove the last sentence.

+    // generate the output to the output buffer.
+    virtual void OnError(Error error) = 0;
+
+    // Called when a buffer with the specified |index| and |port| has been
+    // processed and is no longer used in the accelerator. For input buffer,
+    // it can be filled with new content. For output buffer, it is ready to

[Pawel Osciak, 2016/03/22 08:36:11]

s/buffer, it can be filled/buffers, the Client may fill them/
s/buffer, it is/buffers indicates they are/

[Owen Lin, 2016/03/24 03:01:10]

Done.

+    // be consumed by the client.
+    virtual void OnBufferDone(PortType port,
+                              uint32_t index,
+                              const BufferMetadata& metadata) = 0;
+
+    // Called when the output format has changed or the output format
+    // becomes available at beginning of the stream after initial parsing.
+    virtual void OnOutputFormatChanged(const VideoFormat& format) = 0;
+  };
+
+  virtual bool Initialize(const Config& config, Client* client) = 0;

[Pawel Osciak, 2016/03/22 08:36:11]

Please document.

[Owen Lin, 2016/03/24 03:01:11]

Done.

+
+  // Assigns a shared memory to be used for the accelerator at the specified
+  // port and index. A buffer must be bound before asking the accelerator to

[Pawel Osciak, 2016/03/22 08:36:10]

A buffer must be successfully bound using this method before it can be passed to
the accelerator via UseBuffer(). Already bound buffers may be reused multiple
times without additional calls to BindSharedMemory().

[Owen Lin, 2016/03/24 03:01:10]

Done.

+  // use it via useBuffer().
+  virtual void BindSharedMemory(PortType port,
+                                uint32_t index,
+                                int ashmem_fd,
+                                off_t offset,
+                                size_t length) = 0;
+
+  // Assigns a graphic buffer to be used for the accelerator at the specified

[Pawel Osciak, 2016/03/22 08:36:11]

s/graphic//

[Owen Lin, 2016/03/24 03:01:10]

Done.

+  // port and index. A buffer must be bound before asking the accelerator to
+  // use it via useBuffer().
+  virtual void BindDmabuf(PortType port, uint32_t index, int dmabuf_fd) = 0;
+
+  // Passes a buffer to the accelerator. For input buffer, the accelerator
+  // will process it. For output buffer, the accelerator will output content
+  // to it.
+  virtual void UseBuffer(PortType port,
+                         uint32_t index,
+                         const BufferMetadata& metadata) = 0;
+
+  // Sets the number of output buffers.

[Pawel Osciak, 2016/03/22 08:36:10]

Please document whether this can fail and what happens then.

[Owen Lin, 2016/03/24 03:01:10]

This is not likely to fail in current implementation. Kung-Che did suggest add a
limits to prevent malicious clients.

+  virtual void SetNumberOfOutputBuffers(size_t number) = 0;
+
+  // Resets the accelerator. After this function, all buffers won't be
+  // accessed by the accelerator and there won't be more callbacks.
+  virtual void Reset() = 0;
+
+  virtual ~ArcVideoAccelerator() {}
+};
+
+}  // namespace arc
+}  // namespace chromeos
+
+#endif  // CHROME_GPU_ARC_VIDEO_ACCELERATOR_H_