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fix static when rotating away from source

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This commit is contained in:
ZappoMan 2014-09-16 20:40:09 -07:00
parent 7b3f61ddc2
commit 9494af6153
1 changed files with 80 additions and 38 deletions
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118
assignment-client/src/audio/AudioMixer.cpp
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@ -255,48 +255,90 @@ int AudioMixer::addStreamToMixForListeningNodeWithStream(PositionalAudioStream*
if (!streamToAdd->isStereo()) {
// this is a mono stream, which means it gets full attenuation and spatialization
// if the bearing relative angle to source is > 0 then the delayed channel is the right one
int delayedChannelOffset = (bearingRelativeAngleToSource > 0.0f) ? 1 : 0;
int goodChannelOffset = delayedChannelOffset == 0 ? 1 : 0;
int16_t correctStreamSample[2], delayStreamSample[2];
int delayedChannelIndex = 0;
const int SINGLE_STEREO_OFFSET = 2;
float attenuationAndFade = attenuationCoefficient * repeatedFrameFadeFactor;
for (int s = 0; s < NETWORK_BUFFER_LENGTH_SAMPLES_STEREO; s += 4) {
// setup the int16_t variables for the two sample sets
correctStreamSample[0] = streamPopOutput[s / 2] * attenuationAndFade;
correctStreamSample[1] = streamPopOutput[(s / 2) + 1] * attenuationAndFade;
delayedChannelIndex = s + (numSamplesDelay * 2) + delayedChannelOffset;
delayStreamSample[0] = correctStreamSample[0] * weakChannelAmplitudeRatio;
delayStreamSample[1] = correctStreamSample[1] * weakChannelAmplitudeRatio;
_clientSamples[s + goodChannelOffset] += correctStreamSample[0];
_clientSamples[s + goodChannelOffset + SINGLE_STEREO_OFFSET] += correctStreamSample[1];
_clientSamples[delayedChannelIndex] += delayStreamSample[0];
_clientSamples[delayedChannelIndex + SINGLE_STEREO_OFFSET] += delayStreamSample[1];
}
if (numSamplesDelay > 0) {
// if there was a sample delay for this stream, we need to pull samples prior to the popped output
// to stick at the beginning
float attenuationAndWeakChannelRatioAndFade = attenuationCoefficient * weakChannelAmplitudeRatio * repeatedFrameFadeFactor;
AudioRingBuffer::ConstIterator delayStreamPopOutput = streamPopOutput - numSamplesDelay;
// we need to do several things in this process:
// 1) convert from mono to stereo by copying each input sample into the left and right output samples
// 2) apply an attenuation AND fade to all samples (left and right)
// 3) based on the bearing relative angle to the source we will weaken and delay either the left or
// right channel of the input into the output
// 4) because one of these channels is delayed, we will need to use historical samples from
// the input stream for that delayed channel
// TODO: delayStreamPopOutput may be inside the last frame written if the ringbuffer is completely full
// Mono input to stereo output (item 1 above)
int OUTPUT_SAMPLES_PER_INPUT_SAMPLE = 2;
int inputSampleCount = NETWORK_BUFFER_LENGTH_SAMPLES_STEREO / OUTPUT_SAMPLES_PER_INPUT_SAMPLE;
int maxOutputIndex = NETWORK_BUFFER_LENGTH_SAMPLES_STEREO;
// attenuation and fade applied to all samples (item 2 above)
float attenuationAndFade = attenuationCoefficient * repeatedFrameFadeFactor;
// determine which side is weak and delayed (item 3 above)
bool rightSideWeakAndDelayed = (bearingRelativeAngleToSource > 0.0f);
// since we're converting from mono to stereo, we'll use these two indices to step through
// the output samples. we'll increment each index independently in the loop
int leftDestinationIndex = 0;
int rightDestinationIndex = 1;
// One of our two channels will be delayed (determined below). We'll use this index to step
// through filling in our output with the historical samples for the delayed channel. (item 4 above)
int delayedChannelHistoricalAudioOutputIndex;
// All samples will be attenuated by at least this much
float leftSideAttenuation = attenuationAndFade;
float rightSideAttenuation = attenuationAndFade;
// The weak/delayed channel will be attenuated by this additional amount
float attenuationAndWeakChannelRatioAndFade = attenuationAndFade * weakChannelAmplitudeRatio;
// Now, based on the determination of which side is weak and delayed, set up our true starting point
// for our indexes, as well as the appropriate attenuation for each channel
if (rightSideWeakAndDelayed) {
delayedChannelHistoricalAudioOutputIndex = rightDestinationIndex;
rightSideAttenuation = attenuationAndWeakChannelRatioAndFade;
rightDestinationIndex += (numSamplesDelay * OUTPUT_SAMPLES_PER_INPUT_SAMPLE);
} else {
delayedChannelHistoricalAudioOutputIndex = leftDestinationIndex;
leftSideAttenuation = attenuationAndWeakChannelRatioAndFade;
leftDestinationIndex += (numSamplesDelay * OUTPUT_SAMPLES_PER_INPUT_SAMPLE);
}
// If there was a sample delay for this stream, we need to pull samples prior to the official start of the input
// and stick those samples at the beginning of the output. We only need to loop through this for the weak/delayed
// side, since the normal side is fully handled below. (item 4 above)
if (numSamplesDelay > 0) {
// TODO: delayStreamSourceSamples may be inside the last frame written if the ringbuffer is completely full
// maybe make AudioRingBuffer have 1 extra frame in its buffer
AudioRingBuffer::ConstIterator delayStreamSourceSamples = streamPopOutput - numSamplesDelay;
for (int i = 0; i < numSamplesDelay; i++) {
int parentIndex = i * 2;
_clientSamples[parentIndex + delayedChannelOffset] += *delayStreamPopOutput * attenuationAndWeakChannelRatioAndFade;
++delayStreamPopOutput;
int16_t originalHistoricalSample = *delayStreamSourceSamples;
_clientSamples[delayedChannelHistoricalAudioOutputIndex] += originalHistoricalSample
* attenuationAndWeakChannelRatioAndFade;
++delayStreamSourceSamples; // move our input pointer
delayedChannelHistoricalAudioOutputIndex += OUTPUT_SAMPLES_PER_INPUT_SAMPLE; // move our output sample
}
}
// Here's where we copy the MONO input to the STEREO output, and account for delay and weak side attenuation
for (int inputSample = 0; inputSample < inputSampleCount; inputSample++) {
int16_t originalSample = streamPopOutput[inputSample];
int16_t leftSideSample = originalSample * leftSideAttenuation;
int16_t rightSideSample = originalSample * rightSideAttenuation;
// since we might be delayed, don't write beyond our maxOutputIndex
if (leftDestinationIndex <= maxOutputIndex) {
_clientSamples[leftDestinationIndex] += leftSideSample;
}
if (rightDestinationIndex <= maxOutputIndex) {
_clientSamples[rightDestinationIndex] += rightSideSample;
}
leftDestinationIndex += OUTPUT_SAMPLES_PER_INPUT_SAMPLE;
rightDestinationIndex += OUTPUT_SAMPLES_PER_INPUT_SAMPLE;
}
} else {
int stereoDivider = streamToAdd->isStereo() ? 1 : 2;
@ -313,7 +355,7 @@ int AudioMixer::addStreamToMixForListeningNodeWithStream(PositionalAudioStream*
const float TWO_OVER_PI = 2.0f / PI;
const float ZERO_DB = 1.0f;
// const float NEGATIVE_ONE_DB = 0.891f;
//const float NEGATIVE_ONE_DB = 0.891f;
const float NEGATIVE_THREE_DB = 0.708f;
const float NEGATIVE_SIX_DB = 0.501f;