Add VAVDA, the VAAPI Video Decode Accelerator for Intel CPUs.

content/common/gpu/media/vaapi_video_decode_accelerator.h

+// Copyright (c) 2012 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.
+//
+// This file contains an implementation of VideoDecoderAccelerator
+// that utilizes hardware video decoder present on Intel CPUs.
+
+#ifndef CONTENT_COMMON_GPU_MEDIA_VAAPI_VIDEO_DECODE_ACCELERATOR_H_
+#define CONTENT_COMMON_GPU_MEDIA_VAAPI_VIDEO_DECODE_ACCELERATOR_H_
+
+#include "vaapi_h264_decoder.h"
+
+#include <queue>
+#include <utility>
+#include <vector>
+
+#include <GL/glx.h>
+
+#include "base/logging.h"
+#include "base/memory/ref_counted.h"
+#include "base/message_loop.h"
+#include "base/shared_memory.h"
+#include "base/synchronization/condition_variable.h"
+#include "base/synchronization/lock.h"
+#include "base/threading/non_thread_safe.h"
+#include "base/threading/thread.h"
+#include "media/base/bitstream_buffer.h"
+#include "media/video/picture.h"
+#include "media/video/video_decode_accelerator.h"
+
+// Class to provide video decode acceleration for Intel systems with hardware
+// support for it, and on which libva is available.
+// Decoding tasks are performed in a separate decoding thread.
+class VaapiVideoDecodeAccelerator
+  : public media::VideoDecodeAccelerator {

[Ami GONE FROM CHROMIUM, 2012/05/03 23:22:53]

fits on one line now?

[Pawel Osciak, 2012/05/06 17:49:19]

Done.

+ public:
+
+  VaapiVideoDecodeAccelerator(Client* client);
+
+  // media::VideoDecodeAccelerator implementation.
+  virtual bool Initialize(media::VideoCodecProfile profile) OVERRIDE;
+  virtual void Decode(const media::BitstreamBuffer& bitstream_buffer) OVERRIDE;
+  virtual void AssignPictureBuffers(
+      const std::vector<media::PictureBuffer>& buffers) OVERRIDE;
+  virtual void ReusePictureBuffer(int32 picture_buffer_id) OVERRIDE;
+  virtual void Flush() OVERRIDE;
+  virtual void Reset() OVERRIDE;
+  virtual void Destroy() OVERRIDE;
+
+  // Used by user of this class to pass X/GLX state.
+  void SetGlxState(Display* x_display, GLXContext glx_context);
+
+ private:
+  virtual ~VaapiVideoDecodeAccelerator();
+
+  void NotifyInitializeDone();
+
+  // Notify the client that the input buffer has been consumed.
+  void NotifyInputBufferRead(int input_buffer_id);
+
+  // Ensure data has been synced with the output texture and notify
+  // the client it is ready for displaying.
+  void SyncAndNotifyPictureReady(int32 input_id, int32 output_id);
+
+  // Posted by the decoder thread to notify VAVDA that the decoder has
+  // initially parsed the stream is ready to decode. If the pictures have

[Ami GONE FROM CHROMIUM, 2012/05/03 23:22:53]

s/is/and is/ ?

[Pawel Osciak, 2012/05/06 17:49:19]

Done.

+  // not yet been requested, it will request the client to provide |num_pics|
+  // textures of size |width| per |height| and wait for them, otherwise will
+  // post a DecodeTask directly.

[Ami GONE FROM CHROMIUM, 2012/05/03 23:22:53]

The conditionality makes me think this API can be improved but fine to leave for
now.

+  void ReadyToDecode(int num_pics, int width, int height);
+
+  // Notify the client that an error has occurred and decoding cannot continue.
+  void NotifyError(Error error);
+
+  // Map the received input buffer into this process' address space and
+  // queue it for decode.
+  void MapAndQueueNewInputBuffer(
+      const media::BitstreamBuffer& bitstream_buffer);
+
+  // Get a new input buffer from the queue and set it up in decoder. This will
+  // sleep if no input buffers are available. Return true if a new buffer has
+  // been set up, false if an early exit has been requested (due to initiated
+  // reset/flush/destroy).
+  bool GetInputBuffer();
+
+  // Signal the client that the current buffer has been read and can be
+  // returned. Will also release the mapping.
+  void ReturnCurrInputBuffer();

[Ami GONE FROM CHROMIUM, 2012/05/03 23:22:53]

Any reason not to stay consistent with the VDA::Client terminology of
NotifyEndOfBitstreamBuffer?

[Pawel Osciak, 2012/05/06 17:49:19]

It not only notifies, but cleans up as well (mapping) and nulls out
curr_input_buffer_.

+
+  // Get and set up one or more output buffers in the decoder. This will sleep
+  // if no buffers are available. Return true if buffers have been set up or
+  // false if an early exit has been requested (due to initiated
+  // reset/flush/destroy).
+  bool GetOutputBuffers();
+
+  // Initial decode task: get the decoder to the point in the stream from which
+  // it can start/continue decoding. Does not require output buffers and does
+  // not produce output frames. Called either when starting with a new stream
+  // or when playback is to be resumed from a different location in the stream.

[Ami GONE FROM CHROMIUM, 2012/05/03 23:22:53]

s/from a different location in the stream/following a seek./

[Pawel Osciak, 2012/05/06 17:49:19]

Done.

+  void InitialDecodeTask();
+
+  // Decoding task. Will continue decoding given input buffers and sleep
+  // waiting for input/output as needed. Will exit if a reset/flush/destroy
+  // is requested.
+  void DecodeTask();
+
+  // Scheduled after receiving a flush request and executed after the current
+  // decoding task finishes decoding pending inputs. Makes the decoder flush

[Ami GONE FROM CHROMIUM, 2012/05/03 23:22:53]

s/decoder flush/decoder return/

[Pawel Osciak, 2012/05/06 17:49:19]

Done.

+  // all remaining output pictures and puts it in an idle state, ready
+  // to resume if needed and schedules a FinishFlush.
+  void FlushTask();
+
+  // Scheduled by the FlushTask after decoder is flushed to put VAVDA into idle
+  // state and notify the client that flushing has been finished.
+  void FinishFlush();
+
+  // Scheduled after receiving a reset request and executed after the current
+  // decoding task finishes decoding the current frame. Puts the decoder into
+  // an idle state, ready to resume if needed, discarding decoded but not yet
+  // outputted pictures (decoder keeps ownership of their associated picture
+  // buffers). Schedules a FinishReset afterwards.
+  void ResetTask();
+
+  // Scheduled by ResetTask after it's done to put VAVDA into an idle state.
+  // Drops remaining input buffers and notifies the client that reset  has been
+  // finished.
+  void FinishReset();
+
+  // Scheduled on the decoder thread after receiving a Destroy() call from the
+  // client, executed after the current decoding task finishes decoding the
+  // current frame, ignoring any remaining inputs. Cleans up the decoder and
+  // frees all resources.
+  void DestroyTask();
+
+  // Client-provided X/GLX state.
+  Display* x_display_;
+  GLXContext glx_context_;
+
+  // VAVDA state.
+  enum State {
+    // Initialize() not called yet.
+    kUninitialized,
+    // Initialize() succeeded, no initial decode and no pictures requested.

[Ami GONE FROM CHROMIUM, 2012/05/03 23:22:53]

What state is used if Initialize() failed?

[Pawel Osciak, 2012/05/06 17:49:19]

kUninitialized. Added comment about this.

+    kInitialized,
+    // Initial decode finished, requested pictures and waiting for them.
+    kPicturesRequested,
+    // Everything initialized, pictures received and assigned, in decoding.
+    kDecoding,
+    // Resetting, waiting for decoder to finish current task and cleanup.
+    kResetting,
+    // Flushing, waiting for decoder to finish current task and cleanup.
+    kFlushing,
+    // Idle, decoder in state ready to resume decoding.
+    kIdle,
+    // Destroying, waiting for the decoder to finish current task.
+    kDestroying,
+  };
+
+  State state_;
+
+  // An input buffer awaiting consumption, provided by the client.

[Ami GONE FROM CHROMIUM, 2012/05/03 23:22:53]

enums, types, and typedefs belong at the top of the public/protected/private
section according to style guide.
We usually make an exception when a name is used only for a single variable
(typedef'ing right before a member declaration, for example).

[Pawel Osciak, 2012/05/06 17:49:19]

Ok, moving it one member down above its only usage.

+  struct InputBuffer {
+    int32 id;
+    size_t size;
+    scoped_ptr<base::SharedMemory> shm;
+  };
+
+  // Protects input and output buffer queues and state_.
+  base::Lock lock_;
+
+  // Queue for incoming input buffers.
+  typedef std::queue<linked_ptr<InputBuffer> > InputBuffers;
+  InputBuffers input_buffers_;
+  // Signalled when input buffers are queued onto the input_buffers_ queue.
+  base::ConditionVariable input_ready_;
+
+  // Current input buffer at decoder.
+  linked_ptr<InputBuffer> curr_input_buffer_;
+
+  // Queue for incoming input buffers.
+  typedef std::queue<int32> OutputBuffers;
+  OutputBuffers output_buffers_;
+  // Signalled when output buffers are queued onto the output_buffers_ queue.
+  base::ConditionVariable output_ready_;
+
+  // Main thread's message loop

[Ami GONE FROM CHROMIUM, 2012/05/03 23:22:53]

s/Main thread/ChildThread/ ;)

[Pawel Osciak, 2012/05/06 17:49:19]

Done.

+  MessageLoop* message_loop_;
+
+  // To expose client callbacks from VideoDecodeAccelerator.
+  // NOTE: all calls to this object *MUST* be executed on message_loop_.
+  Client* client_;
+
+  base::Thread decoder_thread_;
+  content::VaapiH264Decoder decoder_;
+
+  // Callback passed to the decoder, which it will use to signal readiness
+  // of an output picture to be displayed.
+  void OutputPicCallback(int32 input_id, int32 output_id);
+
+  DISALLOW_COPY_AND_ASSIGN(VaapiVideoDecodeAccelerator);
+};
+
+#endif  // CONTENT_COMMON_GPU_MEDIA_VAAPI_VIDEO_DECODE_ACCELERATOR_H_
+