164 lines
6.3 KiB
C++
164 lines
6.3 KiB
C++
/*
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File: AUTimestampGenerator.h
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Abstract: Part of CoreAudio Utility Classes
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Version: 1.1
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Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple
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Inc. ("Apple") in consideration of your agreement to the following
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terms, and your use, installation, modification or redistribution of
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this Apple software constitutes acceptance of these terms. If you do
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not agree with these terms, please do not use, install, modify or
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redistribute this Apple software.
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In consideration of your agreement to abide by the following terms, and
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subject to these terms, Apple grants you a personal, non-exclusive
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license, under Apple's copyrights in this original Apple software (the
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"Apple Software"), to use, reproduce, modify and redistribute the Apple
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Software, with or without modifications, in source and/or binary forms;
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provided that if you redistribute the Apple Software in its entirety and
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without modifications, you must retain this notice and the following
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text and disclaimers in all such redistributions of the Apple Software.
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Neither the name, trademarks, service marks or logos of Apple Inc. may
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be used to endorse or promote products derived from the Apple Software
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without specific prior written permission from Apple. Except as
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expressly stated in this notice, no other rights or licenses, express or
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implied, are granted by Apple herein, including but not limited to any
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patent rights that may be infringed by your derivative works or by other
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works in which the Apple Software may be incorporated.
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The Apple Software is provided by Apple on an "AS IS" basis. APPLE
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MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
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THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS
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FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND
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OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.
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IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL
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OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,
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MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED
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AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),
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STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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Copyright (C) 2014 Apple Inc. All Rights Reserved.
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*/
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#ifndef __AUTimestampGenerator_h__
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#define __AUTimestampGenerator_h__
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#include <math.h>
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#include "CAHostTimeBase.h"
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#include <stdio.h>
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#define TSGFMT "0x%10qx"
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//#define TSGFMT "%10qd"
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// This class generates a continuously increasing series of timestamps based
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// on a series of potentially discontinuous timestamps (as can be delivered from
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// CoreAudio in the event of an overload or major engine change).
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// N.B.: "output" = downstream (source) timestamp
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// "input" = upstream (derived) timestamp
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class AUTimestampGenerator {
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public:
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AUTimestampGenerator(bool hostTimeDiscontinuityCorrection = false)
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{
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mState.mStartInputAtZero = true;
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mState.mBypassed = false;
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mState.mHostTimeDiscontinuityCorrection = hostTimeDiscontinuityCorrection;
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#if DEBUG
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mVerbosity = 0;
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snprintf(mDebugName, sizeof(mDebugName), "tsg @ %p", this);
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#endif
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// CAHostTimeBase should be used instead of the calls in <CoreAudio/HostTime.h>
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// we make this call here to ensure that this is initialized, otherwise the first time
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// you do actually call CAHostTimeBase to do work, can be on the render thread, and lead to unwanted VM faults
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CAHostTimeBase::GetFrequency();
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Reset();
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}
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void SetStartInputAtZero(bool b) { mState.mStartInputAtZero = b; }
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bool GetStartInputAtZero() const { return mState.mStartInputAtZero; }
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// bypassing is intended for a narrow special case. the upstream sample time will always be the same as the downstream time.
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void SetBypassed(bool b) { mState.mBypassed = b; }
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bool GetBypassed() const { return mState.mBypassed; }
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// Call this to reset the timeline.
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void Reset()
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{
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mState.mCurrentInputTime.mSampleTime = 0.;
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mState.mNextInputSampleTime = 0.;
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mState.mCurrentOutputTime.mSampleTime = 0.;
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mState.mNextOutputSampleTime = 0.;
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mState.mLastOutputTime.mFlags = 0;
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mState.mRateScalarAdj = 1.;
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mFirstTime = true;
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#if DEBUG
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if (mVerbosity)
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printf("%-20.20s: Reset\n", mDebugName);
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#endif
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}
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// Call this once per render cycle with the downstream timestamp.
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// expectedDeltaFrames is the expected difference between the current and NEXT
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// downstream timestamps.
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// sampleRate is the OUTPUT sample rate.
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void AddOutputTime(const AudioTimeStamp &inTimeStamp, Float64 expectedDeltaFrames, double outputSampleRate, double rateScalarAdj=1.0);
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// Call this once per render cycle to obtain the upstream timestamp.
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// framesToAdvance is the number of frames the input timeline is to be
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// advanced during this render cycle.
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// sampleRate is the INPUT sample rate.
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const AudioTimeStamp & GenerateInputTime(Float64 framesToAdvance, double inputSampleRate, bool advanceHostTime = false);
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// this can be called to override the setting of the next input sample time in GenerateInputTime
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void Advance(Float64 framesToAdvance)
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{
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#if DEBUG
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if (mVerbosity > 1)
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printf("%-20.20s: ADVANCE in = " TSGFMT " advance = " TSGFMT "\n", mDebugName, (SInt64)mState.mCurrentInputTime.mSampleTime, (SInt64)framesToAdvance);
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#endif
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mState.mNextInputSampleTime = mState.mCurrentInputTime.mSampleTime + framesToAdvance;
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}
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struct State {
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AudioTimeStamp mCurrentInputTime;
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Float64 mNextInputSampleTime;
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Float64 mNextOutputSampleTime;
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Float64 mInputSampleTimeForOutputPull;
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AudioTimeStamp mLastOutputTime;
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AudioTimeStamp mCurrentOutputTime;
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bool mStartInputAtZero; // if true, input timeline starts at 0, else it starts
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// synced with the output timeline
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bool mDiscontinuous;
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bool mBypassed;
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Float64 mDiscontinuityDeltaSamples;
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double mRateScalarAdj;
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bool mHostTimeDiscontinuityCorrection; // If true, propagate timestamp discontinuities using host time.
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};
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void GetState(State& outState) const { outState = mState; }
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void SetState(State const& inState) { mState = inState; mFirstTime = false; }
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private:
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struct State mState;
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bool mFirstTime;
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#if DEBUG
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public:
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int mVerbosity;
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char mDebugName[64];
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#endif
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};
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#endif // __AUTimestampGenerator_h__
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