/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef WebAudioUtils_h_
#define WebAudioUtils_h_
#include <cmath>
#include <limits>
#include "mozilla/TypeTraits.h"
#include "mozilla/FloatingPoint.h"
#include "MediaSegment.h"
// Forward declaration
typedef struct SpeexResamplerState_ SpeexResamplerState;
namespace mozilla {
class AudioNodeStream;
extern LazyLogModule gWebAudioAPILog;
#define WEB_AUDIO_API_LOG(...) \
MOZ_LOG(gWebAudioAPILog, LogLevel::Debug, (__VA_ARGS__))
namespace dom {
struct AudioTimelineEvent;
namespace WebAudioUtils {
// 32 is the minimum required by the spec for createBuffer() and
// createScriptProcessor() and matches what is used by Blink. The limit
// protects against large memory allocations.
const size_t MaxChannelCount = 32;
// AudioContext::CreateBuffer() "must support sample-rates in at least the
// range 22050 to 96000."
const uint32_t MinSampleRate = 8000;
const uint32_t MaxSampleRate = 192000;
inline bool FuzzyEqual(float v1, float v2)
{
using namespace std;
return fabsf(v1 - v2) < 1e-7f;
}
inline bool FuzzyEqual(double v1, double v2)
{
using namespace std;
return fabs(v1 - v2) < 1e-7;
}
/**
* Computes an exponential smoothing rate for a time based variable
* over aDuration seconds.
*/
inline double ComputeSmoothingRate(double aDuration, double aSampleRate)
{
return 1.0 - std::exp(-1.0 / (aDuration * aSampleRate));
}
/**
* Converts an AudioTimelineEvent's floating point time values to tick values
* with respect to a destination AudioNodeStream.
*
* This needs to be called for each AudioTimelineEvent that gets sent to an
* AudioNodeEngine, on the engine side where the AudioTimlineEvent is
* received. This means that such engines need to be aware of their
* destination streams as well.
*/
void ConvertAudioTimelineEventToTicks(AudioTimelineEvent& aEvent,
AudioNodeStream* aDest);
/**
* Converts a linear value to decibels. Returns aMinDecibels if the linear
* value is 0.
*/
inline float ConvertLinearToDecibels(float aLinearValue, float aMinDecibels)
{
return aLinearValue ? 20.0f * std::log10(aLinearValue) : aMinDecibels;
}
/**
* Converts a decibel value to a linear value.
*/
inline float ConvertDecibelsToLinear(float aDecibels)
{
return std::pow(10.0f, 0.05f * aDecibels);
}
/**
* Converts a decibel to a linear value.
*/
inline float ConvertDecibelToLinear(float aDecibel)
{
return std::pow(10.0f, 0.05f * aDecibel);
}
inline void FixNaN(double& aDouble)
{
if (IsNaN(aDouble) || IsInfinite(aDouble)) {
aDouble = 0.0;
}
}
inline double DiscreteTimeConstantForSampleRate(double timeConstant, double sampleRate)
{
return 1.0 - std::exp(-1.0 / (sampleRate * timeConstant));
}
inline bool IsTimeValid(double aTime)
{
return aTime >= 0 && aTime <= (MEDIA_TIME_MAX >> TRACK_RATE_MAX_BITS);
}
/**
* Converts a floating point value to an integral type in a safe and
* platform agnostic way. The following program demonstrates the kinds
* of ways things can go wrong depending on the CPU architecture you're
* compiling for:
*
* #include <stdio.h>
* volatile float r;
* int main()
* {
* unsigned int q;
* r = 1e100;
* q = r;
* printf("%f %d\n", r, q);
* r = -1e100;
* q = r;
* printf("%f %d\n", r, q);
* r = 1e15;
* q = r;
* printf("%f %x\n", r, q);
* r = 0/0.;
* q = r;
* printf("%f %d\n", r, q);
* }
*
* This program, when compiled for unsigned int, generates the following
* results depending on the architecture:
*
* x86 and x86-64
* ---
* inf 0
* -inf 0
* 999999995904.000000 -727384064 d4a50000
* nan 0
*
* ARM
* ---
* inf -1
* -inf 0
* 999999995904.000000 -1
* nan 0
*
* When compiled for int, this program generates the following results:
*
* x86 and x86-64
* ---
* inf -2147483648
* -inf -2147483648
* 999999995904.000000 -2147483648
* nan -2147483648
*
* ARM
* ---
* inf 2147483647
* -inf -2147483648
* 999999995904.000000 2147483647
* nan 0
*
* Note that the caller is responsible to make sure that the value
* passed to this function is not a NaN. This function will abort if
* it sees a NaN.
*/
template <typename IntType, typename FloatType>
IntType TruncateFloatToInt(FloatType f)
{
using namespace std;
static_assert(mozilla::IsIntegral<IntType>::value == true,
"IntType must be an integral type");
static_assert(mozilla::IsFloatingPoint<FloatType>::value == true,
"FloatType must be a floating point type");
if (mozilla::IsNaN(f)) {
// It is the responsibility of the caller to deal with NaN values.
// If we ever get to this point, we have a serious bug to fix.
NS_RUNTIMEABORT("We should never see a NaN here");
}
if (f > FloatType(numeric_limits<IntType>::max())) {
// If the floating point value is outside of the range of maximum
// integral value for this type, just clamp to the maximum value.
return numeric_limits<IntType>::max();
}
if (f < FloatType(numeric_limits<IntType>::min())) {
// If the floating point value is outside of the range of minimum
// integral value for this type, just clamp to the minimum value.
return numeric_limits<IntType>::min();
}
// Otherwise, this conversion must be well defined.
return IntType(f);
}
void Shutdown();
int
SpeexResamplerProcess(SpeexResamplerState* aResampler,
uint32_t aChannel,
const float* aIn, uint32_t* aInLen,
float* aOut, uint32_t* aOutLen);
int
SpeexResamplerProcess(SpeexResamplerState* aResampler,
uint32_t aChannel,
const int16_t* aIn, uint32_t* aInLen,
float* aOut, uint32_t* aOutLen);
int
SpeexResamplerProcess(SpeexResamplerState* aResampler,
uint32_t aChannel,
const int16_t* aIn, uint32_t* aInLen,
int16_t* aOut, uint32_t* aOutLen);
void
LogToDeveloperConsole(uint64_t aWindowID, const char* aKey);
} // namespace WebAudioUtils
} // namespace dom
} // namespace mozilla
#endif