1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef ANDROID_AAUDIO_ISOCHRONOUS_CLOCK_MODEL_H 18 #define ANDROID_AAUDIO_ISOCHRONOUS_CLOCK_MODEL_H 19 20 #include <stdint.h> 21 22 namespace aaudio { 23 24 /** 25 * Model an isochronous data stream using occasional timestamps as input. 26 * This can be used to predict the position of the stream at a given time. 27 * 28 * This class is not thread safe and should only be called from one thread. 29 */ 30 class IsochronousClockModel { 31 32 public: 33 IsochronousClockModel(); 34 virtual ~IsochronousClockModel(); 35 36 void start(int64_t nanoTime); 37 void stop(int64_t nanoTime); 38 39 /** 40 * @return true if the model is starting up 41 */ 42 bool isStarting() const; 43 44 /** 45 * @return true if the model is running and producing valid results 46 */ 47 bool isRunning() const; 48 49 void processTimestamp(int64_t framePosition, int64_t nanoTime); 50 51 /** 52 * @param sampleRate rate of the stream in frames per second 53 */ 54 void setSampleRate(int32_t sampleRate); 55 56 void setPositionAndTime(int64_t framePosition, int64_t nanoTime); 57 getSampleRate()58 int32_t getSampleRate() const { 59 return mSampleRate; 60 } 61 62 /** 63 * This must be set accurately in order to track the isochronous stream. 64 * 65 * @param framesPerBurst number of frames that stream advance at one time. 66 */ 67 void setFramesPerBurst(int32_t framesPerBurst); 68 getFramesPerBurst()69 int32_t getFramesPerBurst() const { 70 return mFramesPerBurst; 71 } 72 73 /** 74 * Calculate an estimated time when the stream will be at that position. 75 * 76 * @param framePosition position of the stream in frames 77 * @return time in nanoseconds 78 */ 79 int64_t convertPositionToTime(int64_t framePosition) const; 80 81 /** 82 * Calculate an estimated position where the stream will be at the specified time. 83 * 84 * @param nanoTime time of interest 85 * @return position in frames 86 */ 87 int64_t convertTimeToPosition(int64_t nanoTime) const; 88 89 /** 90 * @param framesDelta difference in frames 91 * @return duration in nanoseconds 92 */ 93 int64_t convertDeltaPositionToTime(int64_t framesDelta) const; 94 95 /** 96 * @param nanosDelta duration in nanoseconds 97 * @return frames that stream will advance in that time 98 */ 99 int64_t convertDeltaTimeToPosition(int64_t nanosDelta) const; 100 101 void dump() const; 102 103 private: 104 enum clock_model_state_t { 105 STATE_STOPPED, 106 STATE_STARTING, 107 STATE_SYNCING, 108 STATE_RUNNING 109 }; 110 111 int64_t mMarkerFramePosition; 112 int64_t mMarkerNanoTime; 113 int32_t mSampleRate; 114 int32_t mFramesPerBurst; 115 int32_t mMaxLatenessInNanos; 116 clock_model_state_t mState; 117 118 void update(); 119 }; 120 121 } /* namespace aaudio */ 122 123 #endif //ANDROID_AAUDIO_ISOCHRONOUS_CLOCK_MODEL_H 124