content/common/gpu/media/android_video_encode_accelerator.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_COMMON_GPU_MEDIA_ANDROID_VIDEO_ENCODE_ACCELERATOR_H_
   6 #define CONTENT_COMMON_GPU_MEDIA_ANDROID_VIDEO_ENCODE_ACCELERATOR_H_
   7
   8 #include <list>
   9 #include <queue>
  10 #include <vector>
  11
  12 #include "base/memory/weak_ptr.h"
  13 #include "base/threading/thread_checker.h"
  14 #include "base/timer/timer.h"
  15 #include "base/tuple.h"
  16 #include "content/common/content_export.h"
  17 #include "media/base/android/media_codec_bridge.h"
  18 #include "media/video/video_encode_accelerator.h"
  19
  20 namespace media {
  21 class BitstreamBuffer;
  22 }  // namespace media
  23
  24 namespace content {
  25
  26 // Android-specific implementation of media::VideoEncodeAccelerator, enabling
  27 // hardware-acceleration of video encoding, based on Android's MediaCodec class
  28 // (http://developer.android.com/reference/android/media/MediaCodec.html).  This
  29 // class expects to live and be called on a single thread (the GPU process'
  30 // ChildThread).
  31 class CONTENT_EXPORT AndroidVideoEncodeAccelerator
  32     : public media::VideoEncodeAccelerator {
  33  public:
  34   AndroidVideoEncodeAccelerator();
  35   ~AndroidVideoEncodeAccelerator() override;
  36
  37   // media::VideoEncodeAccelerator implementation.
  38   media::VideoEncodeAccelerator::SupportedProfiles GetSupportedProfiles()
  39       override;
  40   bool Initialize(media::VideoFrame::Format format,
  41                   const gfx::Size& input_visible_size,
  42                   media::VideoCodecProfile output_profile,
  43                   uint32 initial_bitrate,
  44                   Client* client) override;
  45   void Encode(const scoped_refptr<media::VideoFrame>& frame,
  46               bool force_keyframe) override;
  47   void UseOutputBitstreamBuffer(const media::BitstreamBuffer& buffer) override;
  48   void RequestEncodingParametersChange(uint32 bitrate,
  49                                        uint32 framerate) override;
  50   void Destroy() override;
  51
  52  private:
  53   enum {
  54     // Arbitrary choice.
  55     INITIAL_FRAMERATE = 30,
  56     // Until there are non-realtime users, no need for unrequested I-frames.
  57     IFRAME_INTERVAL = kint32max,
  58   };
  59
  60   // Impedance-mismatch fixers: MediaCodec is a poll-based API but VEA is a
  61   // push-based API; these methods turn the crank to make the two work together.
  62   void DoIOTask();
  63   void QueueInput();
  64   void DequeueOutput();
  65
  66   // Returns true if we don't need more or bigger output buffers.
  67   bool DoOutputBuffersSuffice();
  68
  69   // Start & stop |io_timer_| if the time seems right.
  70   void MaybeStartIOTimer();
  71   void MaybeStopIOTimer();
  72
  73   // Used to DCHECK that we are called on the correct thread.
  74   base::ThreadChecker thread_checker_;
  75
  76   // VideoDecodeAccelerator::Client callbacks go here.  Invalidated once any
  77   // error triggers.
  78   scoped_ptr<base::WeakPtrFactory<Client> > client_ptr_factory_;
  79
  80   scoped_ptr<media::VideoCodecBridge> media_codec_;
  81
  82   // Bitstream buffers waiting to be populated & returned to the client.
  83   std::vector<media::BitstreamBuffer> available_bitstream_buffers_;
  84
  85   // Frames waiting to be passed to the codec, queued until an input buffer is
  86   // available.  Each element is a tuple of <Frame, key_frame, enqueue_time>.
  87   typedef std::queue<
  88       base::Tuple<scoped_refptr<media::VideoFrame>, bool, base::Time>>
  89       PendingFrames;
  90   PendingFrames pending_frames_;
  91
  92   // Repeating timer responsible for draining pending IO to the codec.
  93   base::RepeatingTimer<AndroidVideoEncodeAccelerator> io_timer_;
  94
  95   // The difference between number of buffers queued & dequeued at the codec.
  96   int32 num_buffers_at_codec_;
  97
  98   // A monotonically-growing value, used as a fake timestamp just to keep things
  99   // appearing to move forward.
 100   base::TimeDelta fake_input_timestamp_;
 101
 102   // Number of requested output buffers and their capacity.
 103   int num_output_buffers_;          // -1 until RequireBitstreamBuffers.
 104   size_t output_buffers_capacity_;  // 0 until RequireBitstreamBuffers.
 105
 106   uint32 last_set_bitrate_;  // In bps.
 107
 108   DISALLOW_COPY_AND_ASSIGN(AndroidVideoEncodeAccelerator);
 109 };
 110
 111 }  // namespace content
 112
 113 #endif  // CONTENT_COMMON_GPU_MEDIA_ANDROID_VIDEO_ENCODE_ACCELERATOR_H_