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// Copyright 2014 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.
#include <memory>
#include <string>
#include "base/memory/ref_counted.h"
#include "media/base/video_frame.h"
#include "media/capture/capture_export.h"
#include "media/capture/content/video_capture_oracle.h"
#include "media/capture/video/video_capture_buffer_handle.h"
#include "media/capture/video/video_capture_device.h"
namespace base {
class Location;
} // namespace base
namespace media {
struct VideoCaptureParams;
class VideoFrame;
// Thread-safe, refcounted proxy to the VideoCaptureOracle. This proxy wraps
// the VideoCaptureOracle, which decides which frames to capture, and a
// VideoCaptureDevice::Client, which allocates and receives the captured
// frames, in a lock to synchronize state between the two.
class CAPTURE_EXPORT ThreadSafeCaptureOracle
: public base::RefCountedThreadSafe<ThreadSafeCaptureOracle> {
ThreadSafeCaptureOracle(std::unique_ptr<VideoCaptureDevice::Client> client,
const VideoCaptureParams& params,
bool enable_auto_throttling);
// Called when a captured frame is available or an error has occurred.
// If |success| is true then |frame| is valid and |timestamp| indicates when
// the frame was painted.
// If |success| is false, all other parameters are invalid.
typedef base::Callback<void(scoped_refptr<VideoFrame> frame,
base::TimeTicks timestamp,
bool success)>
// Record a change |event| along with its |damage_rect| and |event_time|, and
// then make a decision whether to proceed with capture. The decision is based
// on recent event history, capture activity, and the availability of
// resources.
// If this method returns false, the caller should take no further action.
// Otherwise, |storage| is set to the destination for the video frame capture
// and the caller should initiate capture. Then, once the video frame has
// been populated with its content, or if capture failed, the |callback|
// should be run.
bool ObserveEventAndDecideCapture(VideoCaptureOracle::Event event,
const gfx::Rect& damage_rect,
base::TimeTicks event_time,
scoped_refptr<VideoFrame>* storage,
CaptureFrameCallback* callback);
// Attempt to re-send the last frame to the VideoCaptureDevice::Client.
// Returns true if successful. This can fail if the last frame is no longer
// available in the buffer pool, or if the VideoCaptureOracle decides to
// reject the "passive" refresh.
bool AttemptPassiveRefresh();
base::TimeDelta min_capture_period() const {
return oracle_.min_capture_period();
base::TimeTicks last_time_animation_was_detected() const {
return oracle_.last_time_animation_was_detected();
gfx::Size max_frame_size() const {
return params_.requested_format.frame_size;
// Returns the current capture resolution.
gfx::Size GetCaptureSize() const;
// Updates capture resolution based on the supplied source size and the
// maximum frame size.
void UpdateCaptureSize(const gfx::Size& source_size);
// Stop new captures from happening (but doesn't forget the client).
void Stop();
// Signal an error to the client.
void ReportError(const base::Location& from_here, const std::string& reason);
// Signal device started to the client.
void ReportStarted();
void OnConsumerReportingUtilization(int frame_number, double utilization);
// Helper struct to hold the many arguments needed by DidCaptureFrame(), and
// also ensure that teardown of these objects happens in the correct order if
// bound to an aborted callback.
struct InFlightFrameCapture;
friend class base::RefCountedThreadSafe<ThreadSafeCaptureOracle>;
virtual ~ThreadSafeCaptureOracle();
// Callback invoked on completion of all captures.
void DidCaptureFrame(std::unique_ptr<InFlightFrameCapture> capture,
scoped_refptr<VideoFrame> frame,
base::TimeTicks reference_time,
bool success);
// Callback invoked once all consumers have finished with a delivered video
// frame. Consumer feedback signals are scanned from the frame's |metadata|.
void DidConsumeFrame(int frame_number,
const media::VideoFrameMetadata* metadata);
// Protects everything below it.
mutable base::Lock lock_;
// Recipient of our capture activity.
std::unique_ptr<VideoCaptureDevice::Client> client_;
// Makes the decision to capture a frame.
VideoCaptureOracle oracle_;
// The video capture parameters used to construct the oracle proxy.
const VideoCaptureParams params_;
} // namespace media