content/common/gpu/media/v4l2_image_processor.h

   1 // Copyright 2014 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_V4L2_IMAGE_PROCESSOR_H_
   6 #define CONTENT_COMMON_GPU_MEDIA_V4L2_IMAGE_PROCESSOR_H_
   7
   8 #include <queue>
   9 #include <vector>
  10
  11 #include "base/memory/linked_ptr.h"
  12 #include "base/memory/ref_counted.h"
  13 #include "base/memory/weak_ptr.h"
  14 #include "base/threading/thread.h"
  15 #include "content/common/content_export.h"
  16 #include "content/common/gpu/media/v4l2_device.h"
  17 #include "media/base/video_frame.h"
  18
  19 namespace content {
  20
  21 // Handles image processing accelerators that expose a V4L2 memory-to-memory
  22 // interface. The threading model of this class is the same as for other V4L2
  23 // hardware accelerators (see V4L2VideoDecodeAccelerator) for more details.
  24 class CONTENT_EXPORT V4L2ImageProcessor {
  25  public:
  26   explicit V4L2ImageProcessor(const scoped_refptr<V4L2Device>& device);
  27   virtual ~V4L2ImageProcessor();
  28
  29   // Initializes the processor to convert from |input_format| to |output_format|
  30   // and/or scale from |input_visible_size| to |output_visible_size|.
  31   // Request the output buffers to be of at least |output_allocated_size|.
  32   // Provided |error_cb| will be called if an error occurs.
  33   // Return true if the requested configuration is supported.
  34   bool Initialize(media::VideoFrame::Format input_format,
  35                   media::VideoFrame::Format output_format,
  36                   gfx::Size input_visible_size,
  37                   gfx::Size output_visible_size,
  38                   gfx::Size output_allocated_size,
  39                   const base::Closure& error_cb);
  40
  41   // Returns allocated size required by the processor to be fed with.
  42   gfx::Size input_allocated_size() { return input_allocated_size_; }
  43
  44   // Callback to be used to return a processed image to the client. The client
  45   // should drop references to |frame| once it's done with it.
  46   typedef base::Callback<void(const scoped_refptr<media::VideoFrame>& frame)>
  47       FrameReadyCB;
  48
  49   // Called by client to process |frame|. The resulting processed frame will
  50   // be returned via |cb|. The processor will drop all its references to |frame|
  51   // after it finishes accessing it.
  52   void Process(const scoped_refptr<media::VideoFrame>& frame,
  53                const FrameReadyCB& cb);
  54
  55   // Stop all processing and clean up.
  56   void Destroy();
  57
  58  private:
  59   // Record for input buffers.
  60   struct InputRecord {
  61     InputRecord();
  62     ~InputRecord();
  63     scoped_refptr<media::VideoFrame> frame;
  64     bool at_device;
  65   };
  66
  67   // Record for output buffers.
  68   struct OutputRecord {
  69     OutputRecord();
  70     ~OutputRecord();
  71     bool at_device;
  72     bool at_client;
  73     std::vector<int> fds;
  74   };
  75
  76   // Job record. Jobs are processed in a FIFO order. This is separate from
  77   // InputRecord, because an InputRecord may be returned before we dequeue
  78   // the corresponding output buffer. It can't always be associated with
  79   // an OutputRecord immediately either, because at the time of submission we
  80   // may not have one available (and don't need one to submit input to the
  81   // device).
  82   struct JobRecord {
  83     JobRecord();
  84     ~JobRecord();
  85     scoped_refptr<media::VideoFrame> frame;
  86     FrameReadyCB ready_cb;
  87   };
  88
  89   enum {
  90     // Arbitrarily tuned.
  91     kInputBufferCount = 2,
  92     kOutputBufferCount = 2,
  93   };
  94
  95   void ReuseOutputBuffer(int index);
  96
  97   void Enqueue();
  98   void Dequeue();
  99   bool EnqueueInputRecord();
 100   bool EnqueueOutputRecord();
 101   bool CreateInputBuffers();
 102   bool CreateOutputBuffers();
 103   void DestroyInputBuffers();
 104   void DestroyOutputBuffers();
 105
 106   void NotifyError();
 107   void DestroyTask();
 108
 109   void ProcessTask(scoped_ptr<JobRecord> job_record);
 110   void ServiceDeviceTask();
 111
 112   // Attempt to start/stop device_poll_thread_.
 113   bool StartDevicePoll();
 114   bool StopDevicePoll();
 115
 116   // Ran on device_poll_thread_ to wait for device events.
 117   void DevicePollTask(bool poll_device);
 118
 119   // Size and format-related members remain constant after initialization.
 120   // The visible/allocated sizes of the input frame.
 121   gfx::Size input_visible_size_;
 122   gfx::Size input_allocated_size_;
 123
 124   // The visible/allocated sizes of the destination frame.
 125   gfx::Size output_visible_size_;
 126   gfx::Size output_allocated_size_;
 127
 128   media::VideoFrame::Format input_format_;
 129   media::VideoFrame::Format output_format_;
 130   uint32 input_format_fourcc_;
 131   uint32 output_format_fourcc_;
 132
 133   size_t input_planes_count_;
 134   size_t output_planes_count_;
 135
 136   // Our original calling task runner for the child thread.
 137   const scoped_refptr<base::SingleThreadTaskRunner> child_task_runner_;
 138
 139   // V4L2 device in use.
 140   scoped_refptr<V4L2Device> device_;
 141
 142   // Thread to communicate with the device on.
 143   base::Thread device_thread_;
 144   // Thread used to poll the V4L2 for events only.
 145   base::Thread device_poll_thread_;
 146
 147   // All the below members are to be accessed from device_thread_ only
 148   // (if it's running).
 149   std::queue<linked_ptr<JobRecord> > input_queue_;
 150   std::queue<linked_ptr<JobRecord> > running_jobs_;
 151
 152   // Input queue state.
 153   bool input_streamon_;
 154   // Number of input buffers enqueued to the device.
 155   int input_buffer_queued_count_;
 156   // Input buffers ready to use; LIFO since we don't care about ordering.
 157   std::vector<int> free_input_buffers_;
 158   // Mapping of int index to an input buffer record.
 159   std::vector<InputRecord> input_buffer_map_;
 160
 161   // Output queue state.
 162   bool output_streamon_;
 163   // Number of output buffers enqueued to the device.
 164   int output_buffer_queued_count_;
 165   // Output buffers ready to use; LIFO since we don't care about ordering.
 166   std::vector<int> free_output_buffers_;
 167   // Mapping of int index to an output buffer record.
 168   std::vector<OutputRecord> output_buffer_map_;
 169
 170   // Error callback to the client.
 171   base::Closure error_cb_;
 172
 173   // Weak factory for producing weak pointers on the device_thread_
 174   base::WeakPtrFactory<V4L2ImageProcessor> device_weak_factory_;
 175
 176   DISALLOW_COPY_AND_ASSIGN(V4L2ImageProcessor);
 177 };
 178
 179 }  // namespace content
 180
 181 #endif  // CONTENT_COMMON_GPU_MEDIA_V4L2_IMAGE_PROCESSOR_H_