Add ArcGpuVideoDecodeAccelerator.

content/common/gpu/media/arc/arc_video_accelerator.h

+// Copyright 2015 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 CONTENT_COMMON_GPU_MEDIA_ARC_ARC_VIDEO_ACCELERATOR_H_
+#define CONTENT_COMMON_GPU_MEDIA_ARC_ARC_VIDEO_ACCELERATOR_H_
+
+namespace content {
+namespace arc {
+
+typedef uint32_t status_t;
+
+enum HalPixelFormatExtension {
+  HAL_PIXEL_FORMAT_H264 = 0x34363248,
+  HAL_PIXEL_FORMAT_VP8 = 0x00385056,
+};
+
+enum PortType {
+  PORT_INPUT = 0,
+  PORT_OUTPUT = 1,
+  PORT_COUNT = 2,
+};
+
+enum DeviceType {
+  DEVICE_ENCODER = 0,
+  DEVICE_DECODER = 1,
+};
+
+enum MemoryType {
+  MEMORY_SHARED_MEMORY = 1,

[Pawel Osciak, 2016/01/07 09:22:36]

Is there any specific reason to start with 1 here?

[Owen Lin, 2016/01/12 09:30:23]

I don't really remember why. Let's start with 0 just like others.

+  MEMORY_DMABUF = 2,
+};
+
+enum BufferFlag {
+  BUFFER_FLAG_EOS = 1,
+};
+
+struct BufferMetadata {
+  int64_t timestamp;  // in microseconds
+  uint32_t flags;
+  uint32_t bytes_used;
+};
+
+struct BufferFormat {
+  uint32_t pixel_format;  // the v4l2 fourcc format

[Pawel Osciak, 2016/01/07 09:22:36]

could we call this fourcc and remove v4l2 mention please?

[Owen Lin, 2016/01/12 09:30:23]

Done.

+  uint32_t image_size;

[Pawel Osciak, 2016/01/07 09:22:36]

Is this used?

[Owen Lin, 2016/01/12 09:30:23]

Actually not. Removed.

+  MemoryType memory_type;
+};
+
+struct VideoFormat {
+  uint32_t pixel_format;
+  uint32_t image_size;
+
+  // minimal number of buffers required to process the video.
+  uint32_t min_num_buffers;
+  uint32_t coded_width;
+  uint32_t coded_height;
+  uint32_t crop_left;
+  uint32_t crop_width;
+  uint32_t crop_top;
+  uint32_t crop_height;
+};
+
+// 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
+// rendering and interacting with the Android media framework.
+class ArcVideoAccelerator {
+ public:
+  enum Error {
+    NO_ERROR = 0,
+    ILLEGAL_STATE = 1,
+    INVALID_ARGUMENT = 2,
+    UNREADABLE_INPUT = 3,
+    PLATFORM_FAILURE = 4,
+  };
+
+  // The callbacks of the ArcVideoAccelerator. ArcCodec implmenets this
+  // 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
+    // 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

[Pawel Osciak, 2016/01/07 09:22:36]

|index| |port|

[Owen Lin, 2016/01/12 09:30:23]

Done.

+    // 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
+    // be used.

[Pawel Osciak, 2016/01/07 09:22:36]

s/used/consumed by the client/

[Owen Lin, 2016/01/12 09:30:23]

Done.

+    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 status_t Initialize(DeviceType device, Client* client);

[Pawel Osciak, 2016/01/07 09:22:36]

= 0 here and in methods below please

[Owen Lin, 2016/01/12 09:30:23]

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
+  // use it via useBuffer().
+  virtual status_t BindSharedBuffer(PortType port,

[Pawel Osciak, 2016/01/07 09:22:36]

BindSharedMemory

[Owen Lin, 2016/01/12 09:30:23]

Done.

+                                    uint32_t index,
+                                    int ashmem_fd,

[Pawel Osciak, 2016/01/07 09:22:36]

Could we use base::SharedMemoryHandle here?

[Owen Lin, 2016/01/12 09:30:23]

No, it's a common interface used on both Android and Chromium side.

+                                    size_t offset,
+                                    size_t length);
+
+  // Assigns a graphic buffer to be used for the accelerator at the specified
+  // port and index. A buffer must be bound before asking the accelerator to
+  // use it via useBuffer().
+  virtual status_t BindGraphicBuffer(PortType port,

[Pawel Osciak, 2016/01/07 09:22:36]

BindDmabuf

[Owen Lin, 2016/01/12 09:30:23]

Done.

+                                     uint32_t index,
+                                     int dmabuf_fd);
+
+  // 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 requested buffers. The accelerator may change the
+  // count due to hardware limitation. The caller is responsible to check
+  // the returned value to see if it is acceptable.
+  virtual status_t SetBufferCount(PortType port, size_t* count) = 0;
+
+  // Resets the accelerator. After this function, all buffers won't be
+  // accessed by the accelerator and there won't be more callbacks.

[Pawel Osciak, 2016/01/07 09:22:36]

Does this mean we require the VDA to return all buffers? VDA will not return
outputs on vda->Reset(), only inputs.

[Owen Lin, 2016/01/12 09:30:23]

I have modified the code in ArcCodec to allow VDA keep those buffers. Comment
modified.

+  virtual void Reset() = 0;
+
+  // Sets the buffer format of the given port.
+  virtual status_t SetBufferFormat(PortType port, const BufferFormat& format);

[Pawel Osciak, 2016/01/07 09:22:36]

Sorry, I think I'm forgetting why we needed this call, for inputs I think we
could pass the format to Initialize directly, for outputs we actually get the
format from VDA in ProvidePictureBuffers...

[Owen Lin, 2016/01/12 09:30:23]

For output, we only use it to set the MemoryType. 
On Android side, there are two phases related, 

We call Initialize() in onAllocateComponent(), but call SetBufferFormat() in
onConfigureComponent().

One thing we can do is delaying Initialize() and call it in
onConfigureComponent(). How do you think?

+
+  virtual ~ArcVideoAccelerator();
+
+ private:
+  // DISALLOW_EVIL_CONSTRUCTORS(ArcVideoAccelerator);

[Pawel Osciak, 2016/01/07 09:22:36]

I think we should remove this?

[Owen Lin, 2016/01/12 09:30:23]

Done.

+};
+
+}  // namespace arc
+}  // namespace content
+
+#endif  // CONTENT_COMMON_GPU_MEDIA_ARC_ARC_VIDEO_ACCELERATOR_H_