ExynosVideoEncodeAccelerator

content/common/gpu/media/exynos_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

[Ami GONE FROM CHROMIUM, 2013/08/13 03:25:17]

I assume you applied all my comments from
https://chromiumcodereview.appspot.com/16693005/ ?

[Ami GONE FROM CHROMIUM, 2013/08/13 03:25:17]

Please add perf #s to CL description.

[sheu, 2013/08/13 09:06:25]

I went through the old changelist and applied the comments as I thought
reasonable.  I can go back and tick them if that makes your job easier.

No perf numbers right now :-(

[Ami GONE FROM CHROMIUM, 2013/08/13 18:13:19]

No need for that.
:(

+// found in the LICENSE file.
+
+#ifndef CONTENT_COMMON_GPU_MEDIA_EXYNOS_VIDEO_ENCODE_ACCELERATOR_H_
+#define CONTENT_COMMON_GPU_MEDIA_EXYNOS_VIDEO_ENCODE_ACCELERATOR_H_
+
+#include <list>
+#include <vector>
+
+#include "base/memory/linked_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/threading/thread.h"
+#include "media/video/video_encode_accelerator.h"
+#include "ui/gfx/size.h"
+
+namespace base {
+
+class MessageLoopProxy;
+
+}  // namespace base
+
+namespace media {
+
+class BitstreamBuffer;
+
+}  // namespace media
+
+namespace content {
+
+// This class handles Exynos video encode acceleration by interfacing with the
+// V4L2 devices exported by the Multi Format Codec and GScaler hardware blocks
+// on the Exynos platform.  The threading model of this class is the same as the
+// ExynosVideoDecodeAccelerator (from which class this was designed).
+class ExynosVideoEncodeAccelerator : public media::VideoEncodeAccelerator {
+ public:
+  ExynosVideoEncodeAccelerator(media::VideoEncodeAccelerator::Client* client);

[Ami GONE FROM CHROMIUM, 2013/08/13 03:25:17]

explicit

[sheu, 2013/08/13 09:06:25]

Done.

+  ~ExynosVideoEncodeAccelerator();

[Ami GONE FROM CHROMIUM, 2013/08/13 03:25:17]

virtual

[sheu, 2013/08/13 09:06:25]

Done.

+
+  // media::VideoEncodeAccelerator implementation.
+  virtual void Initialize(media::VideoFrame::Format format,
+                          const gfx::Size& input_visible_size,
+                          media::VideoCodecProfile output_profile,
+                          uint32 initial_bitrate) OVERRIDE;
+  virtual void Encode(const scoped_refptr<media::VideoFrame>& frame,
+                      bool force_keyframe) OVERRIDE;
+  virtual void UseOutputBitstreamBuffer(
+      const media::BitstreamBuffer& buffer) OVERRIDE;
+  virtual void RequestEncodingParametersChange(uint32 bitrate,
+                                               uint32 framerate) OVERRIDE;
+  virtual void Destroy() OVERRIDE;
+
+  static std::vector<media::VideoEncodeAccelerator::SupportedProfile>
+      GetSupportedProfiles();
+
+ private:
+  // Auto-destroy reference for BitstreamBuffer, for tracking buffers passed to
+  // this instance.
+  struct BitstreamBufferRef;
+
+  // Record for GSC input buffers.
+  struct GscInputRecord {
+    GscInputRecord();
+    bool at_device;
+    scoped_refptr<media::VideoFrame> frame;
+  };
+
+  // Record for GSC output buffers.
+  struct GscOutputRecord {
+    GscOutputRecord();
+    bool at_device;
+    int mfc_input;
+  };
+
+  // Record for MFC input buffers.
+  struct MfcInputRecord {
+    MfcInputRecord();
+    bool at_device;
+    int fd[2];
+  };
+
+  // Record for MFC output buffers.
+  struct MfcOutputRecord {
+    MfcOutputRecord();
+    bool at_device;
+    linked_ptr<BitstreamBufferRef> buffer_ref;
+  };
+
+  enum {
+    // These are rather subjectively tuned.
+    kGscInputBufferCount = 2,
+    kGscOutputBufferCount = 2,
+    kMfcOutputBufferCount = 2,
+    // MFC hardware does not report required output buffer size correctly.
+    // Use maximum theoretical size to avoid hanging the hardware.
+    kMfcOutputBufferSize = (2 * 1024 * 1024),
+  };
+
+  // Internal state of the encoder.
+  enum State {
+    kUninitialized,  // Initialize() not yet called.
+    kInitialized,    // Initialize() returned true; ready to start encoding.
+    kEncoding,       // Encoding frames.
+    kError,          // Error in kEncoding state.

[Ami GONE FROM CHROMIUM, 2013/08/13 03:25:17]

Errors can happen in any state, not just kEncoding.

[sheu, 2013/08/13 09:06:25]

Probably an errant search-replace.  Done.

+  };
+
+  //
+  // Encoding tasks, to be run on encode_thread_.
+  //
+
+  // Encode a GSC input buffer.
+  void EncodeTask(const scoped_refptr<media::VideoFrame>& frame,
+                  bool force_keyframe);
+
+  // Add a BitstreamBuffer to the queue of buffers ready to be used for encoder
+  // output.
+  void UseOutputBitstreamBufferTask(scoped_ptr<BitstreamBufferRef> buffer_ref);
+
+  // Device destruction task.
+  void DestroyTask();
+
+  // Service I/O on the V4L2 devices.  This task should only be scheduled from
+  // DevicePollTask().
+  void ServiceDeviceTask();
+
+  // Handle the various device queues.
+  void EnqueueGsc();
+  void DequeueGsc();
+  void EnqueueMfc();
+  void DequeueMfc();
+  // Enqueue a buffer on the corresponding queue.  Returns false on fatal error.
+  bool EnqueueGscInputRecord();
+  bool EnqueueGscOutputRecord();
+  bool EnqueueMfcInputRecord();
+  bool EnqueueMfcOutputRecord();
+
+  // Attempt to start/stop device_poll_thread_.
+  bool StartDevicePoll();
+  bool StopDevicePoll();
+  // Set/clear the device poll interrupt (using device_ooll_interrupt_fd_).

[Ami GONE FROM CHROMIUM, 2013/08/13 03:25:17]

typo: ooll

[sheu, 2013/08/13 09:06:25]

Done.

+  bool SetDevicePollInterrupt();
+  bool ClearDevicePollInterrupt();
+
+  //
+  // 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 encoder_thread_ state (using PostTask to encoder thread, if
+  // necessary).
+  void SetEncoderState(State state);
+
+  //
+  // Other utility functions.  Called on encoder_thread_, unless
+  // encoder_thread_ is not yet started, in which case the child thread can call
+  // these (e.g. in Initialize() or Destroy()).
+  //
+
+  // Change the parameters of encoding.
+  void RequestEncodingParametersChangeTask(uint32 bitrate, uint32 framerate);
+
+  // Create the buffers we need.
+  bool CreateGscInputBuffers();
+  bool CreateGscOutputBuffers();
+  bool SetMfcFormats();
+  bool CreateMfcInputBuffers();
+  bool CreateMfcOutputBuffers();
+
+  // Destroy these buffers.
+  void DestroyGscInputBuffers();
+  void DestroyGscOutputBuffers();
+  void DestroyMfcInputBuffers();
+  void DestroyMfcOutputBuffers();
+
+  // Our original calling message loop for the child thread.
+  const scoped_refptr<base::MessageLoopProxy> child_message_loop_proxy_;
+
+  // WeakPtr<> pointing to |this| for use in posting tasks from the encoder 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 encoder or device thread should use base::Unretained(this),
+  // and tasks posted the other way should use |weak_this_|.
+  base::WeakPtrFactory<ExynosVideoEncodeAccelerator> weak_this_ptr_factory_;
+  base::WeakPtr<ExynosVideoEncodeAccelerator> weak_this_;
+
+  // To expose client callbacks from VideoEncodeAccelerator.
+  // NOTE: all calls to these objects *MUST* be executed on
+  // child_message_loop_proxy_.
+  base::WeakPtrFactory<Client> client_ptr_factory_;
+  base::WeakPtr<Client> client_;
+
+  //
+  // Encoder state, owned and operated by encoder_thread_.
+  // Before encoder_thread_ has started, the encoder state is managed by
+  // the child (main) thread.  After encoder_thread_ has started, the encoder
+  // thread should be the only one managing these.
+  //
+
+  // This thread services tasks posted from the VEA API entry points by the
+  // child thread and device service callbacks posted from the device thread.
+  base::Thread encoder_thread_;
+  // Encoder state.
+  State encoder_state_;
+  // The visible/allocated sizes of the input frame.
+  gfx::Size input_visible_size_;
+  gfx::Size input_allocated_size_;
+  // The visible/allocated sizes of the color-converted intermediate frame.
+  gfx::Size converted_visible_size_;
+  gfx::Size converted_allocated_size_;
+  // The logical visible size of the output frame.
+  gfx::Size output_visible_size_;
+  // The required byte size of output BitstreamBuffers.
+  size_t output_buffer_byte_size_;

[Ami GONE FROM CHROMIUM, 2013/08/13 03:25:17]

This is only ever kMfcOutputBufferSize so seems silly to have extra var for the
future when maybe they differ.

[sheu, 2013/08/13 09:06:25]

Maybe a bit redundant but I think it documents itself a little better.

+
+  // We need to provide the stream header with every keyframe, to allow
+  // midstream decoding restarts.  Store it here.
+  scoped_ptr<uint8[]> stream_header_;

[Ami GONE FROM CHROMIUM, 2013/08/13 03:25:17]

optional: personally I prefer to put this sort of thing in a std::string or a
vector<uint8>

[sheu, 2013/08/13 09:06:25]

Personally I think std::string here is a Pretty Bad Idea.  vector<uint8> is
better but I still think it implies things that I don't need here.

+  size_t stream_header_size_;
+
+  // V4L2 formats for input frames and the output stream.
+  uint32 input_format_fourcc_;
+  uint32 output_format_fourcc_;
+
+  // Bitstream buffers ready to be encoded.

[Ami GONE FROM CHROMIUM, 2013/08/13 03:25:17]

s/Bitstream buffers/Video frames/

[sheu, 2013/08/13 09:06:25]

Done.

+  std::list<scoped_refptr<media::VideoFrame> > encoder_input_queue_;
+
+  // GSC color conversion device.
+  int gsc_fd_;
+  // GSC input queue state.
+  bool gsc_input_streamon_;
+  // GSC input buffers enqueued to device.
+  int gsc_input_buffer_queued_count_;
+  // GSC input buffers ready to use; LIFO since we don't care about ordering.
+  std::vector<int> gsc_free_input_buffers_;
+  // Mapping of int index to GSC input buffer record.
+  std::vector<GscInputRecord> gsc_input_buffer_map_;
+
+  // GSC output queue state.
+  bool gsc_output_streamon_;
+  // GSC output buffers enqueued to device.
+  int gsc_output_buffer_queued_count_;

[Ami GONE FROM CHROMIUM, 2013/08/13 03:25:17]

Is this always equal to
gsc_output_buffer_map_.size() - gsc_free_output_buffers_.size()
?
If so, is it worth tracking separately?

(ditto to the other occurrences of this pattern)

[sheu, 2013/08/13 09:06:25]

For some of these it is.  For example, MFC inputs might be in the GSC->MFC
queue, so it would be both no queued to the hardware and not in its free buffers
queue.

If nothing else it's useful for debugging, so I'd like to leave it.

+  // GSC output buffers ready to use; LIFO since we don't care about ordering.
+  std::vector<int> gsc_free_output_buffers_;
+  // Mapping of int index to GSC output buffer record.
+  std::vector<GscOutputRecord> gsc_output_buffer_map_;
+
+  // MFC input buffers filled by GSC, waiting to be queued to MFC.
+  std::list<int> mfc_ready_input_buffers_;
+
+  // MFC video encoding device.
+  int mfc_fd_;
+
+  // MFC input queue state.
+  bool mfc_input_streamon_;
+  // MFC input buffers enqueued to device.
+  int mfc_input_buffer_queued_count_;
+  // MFC input buffers ready to use; 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_;
+
+  // MFC output queue state.
+  bool mfc_output_streamon_;
+  // MFC output buffers enqueued to device.
+  int mfc_output_buffer_queued_count_;
+  // MFC output buffers ready to use; LIFO since we don't care about ordering.
+  std::vector<int> mfc_free_output_buffers_;
+  // Mapping of int index to MFC output buffer record.
+  std::vector<MfcOutputRecord> mfc_output_buffer_map_;
+
+  // Bitstream buffers ready to be used to return encoded output, as a LIFO
+  // since we don't care about ordering.
+  std::vector<linked_ptr<BitstreamBufferRef> > encoder_output_queue_;
+
+  //
+  // The device polling thread handles notifications of V4L2 device changes.

[Ami GONE FROM CHROMIUM, 2013/08/13 03:25:17]

TODO to lose this thread, like EVEA has.

[sheu, 2013/08/13 09:06:25]

Done.

+  //
+
+  // The thread.
+  base::Thread device_poll_thread_;
+  // eventfd fd to signal device poll thread when its poll() should be
+  // interrupted.
+  int device_poll_interrupt_fd_;
+
+  DISALLOW_COPY_AND_ASSIGN(ExynosVideoEncodeAccelerator);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_GPU_MEDIA_EXYNOS_VIDEO_ENCODE_ACCELERATOR_H_