vda: Rename Exynos VDA to V4L2 VDA

content/common/gpu/media/v4l2_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 the hardware video decoder present on the Exynos SoC.
+// This file contains an implementation of VideoDecodeAccelerator
+// that utilizes hardware video decoders, which expose Video4Linux 2 API
+// (http://linuxtv.org/downloads/v4l-dvb-apis/).
 
-#ifndef CONTENT_COMMON_GPU_MEDIA_EXYNOS_VIDEO_DECODE_ACCELERATOR_H_
-#define CONTENT_COMMON_GPU_MEDIA_EXYNOS_VIDEO_DECODE_ACCELERATOR_H_
+#ifndef CONTENT_COMMON_GPU_MEDIA_V4L2_VIDEO_DECODE_ACCELERATOR_H_
+#define CONTENT_COMMON_GPU_MEDIA_V4L2_VIDEO_DECODE_ACCELERATOR_H_
 
 #include <queue>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "base/memory/linked_ptr.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/threading/thread.h"
 #include "content/common/content_export.h"
 #include "content/common/gpu/media/video_decode_accelerator_impl.h"
 #include "media/base/limits.h"
 #include "media/base/video_decoder_config.h"
 #include "media/video/picture.h"
 #include "ui/gfx/size.h"
 #include "ui/gl/gl_bindings.h"
 
 namespace base {
 class MessageLoopProxy;
 }
 
 namespace content {
 class H264Parser;
 
-// This class handles Exynos video acceleration directly through the V4L2
-// device exported by the Multi Format Codec hardware block.
+// This class handles video accelerators directly through a V4L2 device exported
+// by the hardware blocks.
 //
 // The threading model of this class is driven by the fact that it needs to
 // interface two fundamentally different event queues -- the one Chromium
 // provides through MessageLoop, and the one driven by the V4L2 devices which
 // is waited on with epoll().  There are three threads involved in this class:
 //
 // * The child thread, which is the main GPU process thread which calls the
 //   media::VideoDecodeAccelerator entry points.  Calls from this thread
 //   generally do not block (with the exception of Initialize() and Destroy()).
 //   They post tasks to the decoder_thread_, which actually services the task
 //   and calls back when complete through the
 //   media::VideoDecodeAccelerator::Client interface.
 // * The decoder_thread_, owned by this class.  It services API tasks, through
 //   the *Task() routines, as well as V4L2 device events, through
 //   ServiceDeviceTask().  Almost all state modification is done on this thread.
 // * The device_poll_thread_, owned by this class.  All it does is epoll() on
 //   the V4L2 in DevicePollTask() and schedule a ServiceDeviceTask() on the
 //   decoder_thread_ when something interesting happens.
 //   TODO(sheu): replace this thread with an TYPE_IO decoder_thread_.
 //
 // Note that this class has no locks!  Everything's serviced on the
 // decoder_thread_, so there are no synchronization issues.
 // ... well, there are, but it's a matter of getting messages posted in the
 // right order, not fiddling with locks.
-class CONTENT_EXPORT ExynosVideoDecodeAccelerator
+class CONTENT_EXPORT V4L2VideoDecodeAccelerator
     : public VideoDecodeAcceleratorImpl {
  public:
-  ExynosVideoDecodeAccelerator(
+  V4L2VideoDecodeAccelerator(
       EGLDisplay egl_display,
       Client* client,
       const base::WeakPtr<Client>& io_client_,
       const base::Callback<bool(void)>& make_context_current,
       const scoped_refptr<base::MessageLoopProxy>& io_message_loop_proxy);
-  virtual ~ExynosVideoDecodeAccelerator();
+  virtual ~V4L2VideoDecodeAccelerator();
 
   // media::VideoDecodeAccelerator implementation.
   // Note: Initialize() and Destroy() are synchronous.
   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;
 
   // VideoDecodeAcceleratorImpl implementation.
   virtual bool CanDecodeOnIOThread() OVERRIDE;
 
  private:
   // These are rather subjectively tuned.
   enum {
-    kMfcInputBufferCount = 8,
-    // TODO(posciak): determine MFC input buffer size based on level limits.
+    kInputBufferCount = 8,
+    // TODO(posciak): determine input buffer size based on level limits.
     // See http://crbug.com/255116.
-    kMfcInputBufferMaxSize = 1024 * 1024,
+    kInputBufferMaxSize = 1024 * 1024,
     // Number of output buffers to use for each VDA stage above what's required
     // by the decoder (e.g. DPB size, in H264).  We need
     // media::limits::kMaxVideoFrames to fill up the GpuVideoDecode pipeline,
     // and +1 for a frame in transit.
     kDpbOutputBufferExtraCount = media::limits::kMaxVideoFrames + 1,
   };
 
   // Internal state of the decoder.
   enum State {
     kUninitialized,      // Initialize() not yet called.
     kInitialized,        // Initialize() returned true; ready to start decoding.
     kDecoding,           // DecodeBufferInitial() successful; decoding frames.
     kResetting,          // Presently resetting.
     kAfterReset,         // After Reset(), ready to start decoding again.
     kChangingResolution, // Performing resolution change, all remaining
                          // pre-change frames decoded and processed.
     kError,              // Error in kDecoding state.
   };
 
   enum BufferId {
     kFlushBufferId = -2  // Buffer id for flush buffer, queued by FlushTask().
   };
 
   // File descriptors we need to poll.
   enum PollFds {
-    kPollMfc = (1 << 0),
+    kPoll = (1 << 0),

[Pawel Osciak, 2014/01/07 07:18:12]

This doesn't make too much sense now. Maybe kPollDecoder?

   };
 
   // Auto-destruction reference for BitstreamBuffer, for message-passing from
   // Decode() to DecodeTask().
   struct BitstreamBufferRef;
 
   // Auto-destruction reference for an array of PictureBuffer, for
   // message-passing from AssignPictureBuffers() to AssignPictureBuffersTask().
   struct PictureBufferArrayRef;
 
   // Auto-destruction reference for EGLSync (for message-passing).
   struct EGLSyncKHRRef;
 
   // Record for decoded pictures that can be sent to PictureReady.
   struct PictureRecord;
 
-  // Record for MFC input buffers.
-  struct MfcInputRecord {
-    MfcInputRecord();
-    ~MfcInputRecord();
+  // Record for input buffers.
+  struct InputRecord {
+    InputRecord();
+    ~InputRecord();
     bool at_device;         // held by device.
     void* address;          // mmap() address.
     size_t length;          // mmap() length.
     off_t bytes_used;       // bytes filled in the mmap() segment.
     int32 input_id;         // triggering input_id as given to Decode().
   };
 
-  // Record for MFC output buffers.
-  struct MfcOutputRecord {
-    MfcOutputRecord();
-    ~MfcOutputRecord();
+  // Record for output buffers.
+  struct OutputRecord {
+    OutputRecord();
+    ~OutputRecord();
     bool at_device;         // held by device.
     bool at_client;         // held by client.
     int fds[2];             // file descriptors for each plane.
     EGLImageKHR egl_image;  // EGLImageKHR for the output buffer.
     EGLSyncKHR egl_sync;    // sync the compositor's use of the EGLImage.
     int32 picture_id;       // picture buffer id as returned to PictureReady().
     bool cleared;           // Whether the texture is cleared and safe to render
                             // from. See TextureManager for details.
   };
 
@@ skipping 25 matching lines @@
   bool AppendToInputFrame(const void* data, size_t size);
   // Flush data for one decoded frame.
   bool FlushInputFrame();
 
   // Process an AssignPictureBuffers() API call.  After this, the
   // device_poll_thread_ can be started safely, since we have all our
   // buffers.
   void AssignPictureBuffersTask(scoped_ptr<PictureBufferArrayRef> pic_buffers);
 
   // Service I/O on the V4L2 devices.  This task should only be scheduled from
-  // DevicePollTask().  If |mfc_event_pending| is true, one or more events
-  // on MFC file descriptor are pending.
-  void ServiceDeviceTask(bool mfc_event_pending);
+  // DevicePollTask().  If |event_pending| is true, one or more events
+  // on file descriptor are pending.
+  void ServiceDeviceTask(bool event_pending);
   // Handle the various device queues.
-  void EnqueueMfc();
-  void DequeueMfc();
-  // Handle incoming MFC events.
-  void DequeueMfcEvents();
+  void Enqueue();
+  void Dequeue();
+  // Handle incoming events.
+  void DequeueEvents();
   // Enqueue a buffer on the corresponding queue.
-  bool EnqueueMfcInputRecord();
-  bool EnqueueMfcOutputRecord();
+  bool EnqueueInputRecord();
+  bool EnqueueOutputRecord();
 
   // Process a ReusePictureBuffer() API call.  The API call create an EGLSync
   // object on the main (GPU process) thread; we will record this object so we
   // can wait on it before reusing the buffer.
   void ReusePictureBufferTask(int32 picture_buffer_id,
                               scoped_ptr<EGLSyncKHRRef> egl_sync_ref);
 
   // Flush() task.  Child thread should not submit any more buffers until it
   // receives the NotifyFlushDone callback.  This task will schedule an empty
   // BitstreamBufferRef (with input_id == kFlushBufferId) to perform the flush.
   void FlushTask();
   // Notify the client of a flush completion, if required.  This should be
   // called any time a relevant queue could potentially be emptied: see
   // function definition.
   void NotifyFlushDoneIfNeeded();
 
   // Reset() task.  This task will schedule a ResetDoneTask() that will send
   // the NotifyResetDone callback, then set the decoder state to kResetting so
   // that all intervening tasks will drain.
   void ResetTask();
   // ResetDoneTask() will set the decoder state back to kAfterReset, so
   // subsequent decoding can continue.
   void ResetDoneTask();
 
   // Device destruction task.
   void DestroyTask();
 
   // Attempt to start/stop device_poll_thread_.
   bool StartDevicePoll();
-  // If |keep_mfc_input_state| is true, don't reset MFC input state; used during
+  // If |keep_input_state| is true, don't reset input state; used during
   // resolution change.
-  bool StopDevicePoll(bool keep_mfc_input_state);
+  bool StopDevicePoll(bool keep_input_state);
   // Set/clear the device poll interrupt (using device_poll_interrupt_fd_).
   bool SetDevicePollInterrupt();
   bool ClearDevicePollInterrupt();
 
   void StartResolutionChangeIfNeeded();
   void FinishResolutionChange();
   void ResumeAfterResolutionChange();
 
-  // Try to get output format from MFC, detected after parsing the beginning
+  // Try to get output format, detected after parsing the beginning
   // of the stream. Sets |again| to true if more parsing is needed.
   bool GetFormatInfo(struct v4l2_format* format, bool* again);
-  // Create MFC output buffers for the given |format|.
+  // Create output buffers for the given |format|.
   bool CreateBuffersForFormat(const struct v4l2_format& format);
 
   //
   // Device tasks, to be run on device_poll_thread_.
   //
 
   // The device task.
   void DevicePollTask(unsigned int poll_fds);
 
   //
   // Safe from any thread.
   //
 
   // Error notification (using PostTask() to child thread, if necessary).
   void NotifyError(Error error);
 
   // Set the decoder_thread_ state (using PostTask to decoder thread, if
   // necessary).
   void SetDecoderState(State state);
 
   //
   // Other utility functions.  Called on decoder_thread_, unless
   // decoder_thread_ is not yet started, in which case the child thread can call
   // these (e.g. in Initialize() or Destroy()).
   //
 
   // Create the buffers we need.
-  bool CreateMfcInputBuffers();
-  bool CreateMfcOutputBuffers();
+  bool CreateInputBuffers();
+  bool CreateOutputBuffers();
 
   //
   // Methods run on child thread.
   //
 
   // Destroy buffers.
-  void DestroyMfcInputBuffers();
-  void DestroyMfcOutputBuffers();
+  void DestroyInputBuffers();
+  void DestroyOutputBuffers();
   void ResolutionChangeDestroyBuffers();
 
   // Send decoded pictures to PictureReady.
   void SendPictureReady();
 
   // Callback that indicates a picture has been cleared.
   void PictureCleared();
 
   // Our original calling message loop for the child thread.
   scoped_refptr<base::MessageLoopProxy> child_message_loop_proxy_;
 
   // Message loop of the IO thread.
   scoped_refptr<base::MessageLoopProxy> io_message_loop_proxy_;
 
   // WeakPtr<> pointing to |this| for use in posting tasks from the decoder or
   // device worker threads back to the child thread.  Because the worker threads
   // are members of this class, any task running on those threads is guaranteed
   // that this object is still alive.  As a result, tasks posted from the child
   // thread to the decoder or device thread should use base::Unretained(this),
   // and tasks posted the other way should use |weak_this_|.
-  base::WeakPtr<ExynosVideoDecodeAccelerator> weak_this_;
+  base::WeakPtr<V4L2VideoDecodeAccelerator> weak_this_;
 
   // To expose client callbacks from VideoDecodeAccelerator.
   // NOTE: all calls to these objects *MUST* be executed on
   // child_message_loop_proxy_.
   base::WeakPtrFactory<Client> client_ptr_factory_;
   base::WeakPtr<Client> client_;
   // Callbacks to |io_client_| must be executed on |io_message_loop_proxy_|.
   base::WeakPtr<Client> io_client_;
 
   //
   // Decoder state, owned and operated by decoder_thread_.
   // Before decoder_thread_ has started, the decoder state is managed by
   // the child (main) thread.  After decoder_thread_ has started, the decoder
   // thread should be the only one managing these.
   //
 
   // This thread services tasks posted from the VDA API entry points by the
   // child thread and device service callbacks posted from the device thread.
   base::Thread decoder_thread_;
   // Decoder state machine state.
   State decoder_state_;
   // BitstreamBuffer we're presently reading.
   scoped_ptr<BitstreamBufferRef> decoder_current_bitstream_buffer_;
   // FlushTask() and ResetTask() should not affect buffers that have been
   // queued afterwards.  For flushing or resetting the pipeline then, we will
   // delay these buffers until after the flush or reset completes.
   int decoder_delay_bitstream_buffer_id_;
-  // MFC input buffer we're presently filling.
+  // input buffer we're presently filling.
   int decoder_current_input_buffer_;
   // We track the number of buffer decode tasks we have scheduled, since each
   // task execution should complete one buffer.  If we fall behind (due to
   // resource backpressure, etc.), we'll have to schedule more to catch up.
   int decoder_decode_buffer_tasks_scheduled_;
   // Picture buffers held by the client.
   int decoder_frames_at_client_;
   // Are we flushing?
   bool decoder_flushing_;
   // Got a notification from driver that it reached resolution change point
   // in the stream.
   bool resolution_change_pending_;
   // Got a reset request while we were performing resolution change.
   bool resolution_change_reset_pending_;
   // Input queue for decoder_thread_: BitstreamBuffers in.
   std::queue<linked_ptr<BitstreamBufferRef> > decoder_input_queue_;
   // For H264 decode, hardware requires that we send it frame-sized chunks.
   // We'll need to parse the stream.
   scoped_ptr<content::H264Parser> decoder_h264_parser_;
   // Set if the decoder has a pending incomplete frame in an input buffer.
   bool decoder_partial_frame_pending_;
 
   //
   // Hardware state and associated queues.  Since decoder_thread_ services
   // the hardware, decoder_thread_ owns these too.
   //
 
-  // Completed decode buffers, waiting for MFC.
-  std::queue<int> mfc_input_ready_queue_;
+  // Completed decode buffers.
+  std::queue<int> input_ready_queue_;
 
-  // MFC decode device.
-  int mfc_fd_;
+  // decode device.

[Pawel Osciak, 2014/01/07 07:18:12]

Comments should start with capital letters (be sentences in general).
Here and everywhere else.

+  int fd_;
 
-  // MFC input buffer state.
-  bool mfc_input_streamon_;
-  // MFC input buffers enqueued to device.
-  int mfc_input_buffer_queued_count_;
+  // input buffer state.
+  bool input_streamon_;
+  // input buffers enqueued to device.
+  int input_buffer_queued_count_;
   // Input buffers ready to use, as a LIFO since we don't care about ordering.
-  std::vector<int> mfc_free_input_buffers_;
-  // Mapping of int index to MFC input buffer record.
-  std::vector<MfcInputRecord> mfc_input_buffer_map_;
+  std::vector<int> free_input_buffers_;
+  // Mapping of int index to input buffer record.
+  std::vector<InputRecord> input_buffer_map_;
 
-  // MFC output buffer state.
-  bool mfc_output_streamon_;
-  // MFC output buffers enqueued to device.
-  int mfc_output_buffer_queued_count_;
+  // output buffer state.
+  bool output_streamon_;
+  // output buffers enqueued to device.
+  int output_buffer_queued_count_;
   // Output buffers ready to use, as a FIFO since we want oldest-first to hide
   // synchronization latency with GL.
-  std::queue<int> mfc_free_output_buffers_;
-  // Mapping of int index to MFC output buffer record.
-  std::vector<MfcOutputRecord> mfc_output_buffer_map_;
-  // MFC output pixel format.
-  uint32 mfc_output_buffer_pixelformat_;
+  std::queue<int> free_output_buffers_;
+  // Mapping of int index to output buffer record.
+  std::vector<OutputRecord> output_buffer_map_;
+  // output pixel format.
+  uint32 output_buffer_pixelformat_;
   // Required size of DPB for decoding.
-  int mfc_output_dpb_size_;
+  int output_dpb_size_;
 
   // Pictures that are ready but not sent to PictureReady yet.
   std::queue<PictureRecord> pending_picture_ready_;
 
   // The number of pictures that are sent to PictureReady and will be cleared.
   int picture_clearing_count_;
 
   // Output picture size.
   gfx::Size frame_buffer_size_;
 
@@ skipping 13 matching lines @@
 
   // Make our context current before running any EGL entry points.
   base::Callback<bool(void)> make_context_current_;
 
   // EGL state
   EGLDisplay egl_display_;
 
   // The codec we'll be decoding for.
   media::VideoCodecProfile video_profile_;
 
-  DISALLOW_COPY_AND_ASSIGN(ExynosVideoDecodeAccelerator);
+  DISALLOW_COPY_AND_ASSIGN(V4L2VideoDecodeAccelerator);
 };
 
 }  // namespace content
 
-#endif  // CONTENT_COMMON_GPU_MEDIA_EXYNOS_VIDEO_DECODE_ACCELERATOR_H_
+#endif  // CONTENT_COMMON_GPU_MEDIA_V4L2_VIDEO_DECODE_ACCELERATOR_H_