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