| // 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. |
| |
| #ifndef MEDIA_BASE_WALL_CLOCK_TIME_SOURCE_H_ |
| #define MEDIA_BASE_WALL_CLOCK_TIME_SOURCE_H_ |
| |
| #include "base/memory/scoped_ptr.h" |
| #include "base/synchronization/lock.h" |
| #include "media/base/media_export.h" |
| #include "media/base/time_source.h" |
| |
| namespace base { |
| class TickClock; |
| } |
| |
| namespace media { |
| |
| // A time source that uses interpolation based on the system clock. |
| class MEDIA_EXPORT WallClockTimeSource : public TimeSource { |
| public: |
| WallClockTimeSource(); |
| virtual ~WallClockTimeSource(); |
| |
| // TimeSource implementation. |
| virtual void StartTicking() OVERRIDE; |
| virtual void StopTicking() OVERRIDE; |
| virtual void SetPlaybackRate(float playback_rate) OVERRIDE; |
| virtual void SetMediaTime(base::TimeDelta time) OVERRIDE; |
| virtual base::TimeDelta CurrentMediaTime() OVERRIDE; |
| virtual base::TimeDelta CurrentMediaTimeForSyncingVideo() OVERRIDE; |
| |
| void SetTickClockForTesting(scoped_ptr<base::TickClock> tick_clock); |
| |
| private: |
| base::TimeDelta CurrentMediaTime_Locked(); |
| |
| scoped_ptr<base::TickClock> tick_clock_; |
| bool ticking_; |
| |
| // While ticking we can interpolate the current media time by measuring the |
| // delta between our reference ticks and the current system ticks and scaling |
| // that time by the playback rate. |
| float playback_rate_; |
| base::TimeDelta base_time_; |
| base::TimeTicks reference_wall_ticks_; |
| |
| // TODO(scherkus): Remove internal locking from this class after access to |
| // Renderer::CurrentMediaTime() is single threaded http://crbug.com/370634 |
| base::Lock lock_; |
| |
| DISALLOW_COPY_AND_ASSIGN(WallClockTimeSource); |
| }; |
| |
| } // namespace media |
| |
| #endif // MEDIA_BASE_WALL_CLOCK_TIME_SOURCE_H_ |