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| 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 CHROMECAST_PUBLIC_MEDIA_MEDIA_CLOCK_DEVICE_H_ |
| 6 #define CHROMECAST_PUBLIC_MEDIA_MEDIA_CLOCK_DEVICE_H_ |
| 7 |
| 8 #include <string> |
| 9 |
| 10 namespace chromecast { |
| 11 namespace media { |
| 12 |
| 13 // Interface for platform-specific pipeline clock. |
| 14 // Pipeline clocks follow this state machine: |
| 15 // ------------------- |
| 16 // | | |
| 17 // v | |
| 18 // kUninitialized --> kIdle --------- kRunning |
| 19 // |
| 20 // {any state} --> kError |
| 21 // |
| 22 // Notes: |
| 23 // - Hardware resources should be acquired when transitioning from the |
| 24 // |kUninitialized| state to the |kIdle| state. |
| 25 // - The initial value of the timeline will only be set in the kIdle state. |
| 26 class MediaClockDevice { |
| 27 public: |
| 28 enum State { |
| 29 kStateUninitialized, |
| 30 kStateIdle, |
| 31 kStateRunning, |
| 32 kStateError, |
| 33 }; |
| 34 |
| 35 virtual ~MediaClockDevice() {} |
| 36 |
| 37 // Returns the current state of the media clock. |
| 38 virtual State GetState() const = 0; |
| 39 |
| 40 // Changes the state and performs any necessary transitions. |
| 41 // Returns true when successful. |
| 42 virtual bool SetState(State new_state) = 0; |
| 43 |
| 44 // Sets the initial value of the timeline in microseconds. |
| 45 // Will only be invoked in state kStateIdle. |
| 46 // Returns true when successful. |
| 47 virtual bool ResetTimeline(int64_t time_microseconds) = 0; |
| 48 |
| 49 // Sets the clock rate. |
| 50 // |rate| == 0 means the clock is not progressing and that the renderer |
| 51 // tied to this media clock should pause rendering. |
| 52 // Will only be invoked in states kStateIdle or kStateRunning. |
| 53 virtual bool SetRate(float rate) = 0; |
| 54 |
| 55 // Retrieves the media clock time in microseconds. |
| 56 // Will only be invoked in states kStateIdle or kStateRunning. |
| 57 virtual int64_t GetTimeMicroseconds() = 0; |
| 58 }; |
| 59 |
| 60 } // namespace media |
| 61 } // namespace chromecast |
| 62 |
| 63 #endif // CHROMECAST_MEDIA_CMA_BACKEND_MEDIA_CLOCK_DEVICE_H_ |
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