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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <memory>
#include "oboe/Oboe.h"
#include "opensles/AudioStreamBuffered.h"
#include "common/AudioClock.h"
namespace oboe {
constexpr int kDefaultBurstsPerBuffer = 16; // arbitrary, allows dynamic latency tuning
constexpr int kMinBurstsPerBuffer = 4; // arbitrary, allows dynamic latency tuning
constexpr int kMinFramesPerBuffer = 48 * 32; // arbitrary
/*
* AudioStream with a FifoBuffer
*/
AudioStreamBuffered::AudioStreamBuffered(const AudioStreamBuilder &builder)
: AudioStream(builder) {
}
void AudioStreamBuffered::allocateFifo() {
// If the caller does not provide a callback use our own internal
// callback that reads data from the FIFO.
if (usingFIFO()) {
// FIFO is configured with the same format and channels as the stream.
int32_t capacityFrames = getBufferCapacityInFrames();
if (capacityFrames == oboe::kUnspecified) {
capacityFrames = getFramesPerBurst() * kDefaultBurstsPerBuffer;
} else {
int32_t minFramesPerBufferByBursts = getFramesPerBurst() * kMinBurstsPerBuffer;
if (capacityFrames <= minFramesPerBufferByBursts) {
capacityFrames = minFramesPerBufferByBursts;
} else {
capacityFrames = std::max(kMinFramesPerBuffer, capacityFrames);
// round up to nearest burst
int32_t numBursts = (capacityFrames + getFramesPerBurst() - 1)
/ getFramesPerBurst();
capacityFrames = numBursts * getFramesPerBurst();
}
}
// TODO consider using std::make_unique if we require c++14
mFifoBuffer.reset(new FifoBuffer(getBytesPerFrame(), capacityFrames));
mBufferCapacityInFrames = capacityFrames;
}
}
void AudioStreamBuffered::updateFramesWritten() {
if (mFifoBuffer) {
mFramesWritten = static_cast<int64_t>(mFifoBuffer->getWriteCounter());
} // or else it will get updated by processBufferCallback()
}
void AudioStreamBuffered::updateFramesRead() {
if (mFifoBuffer) {
mFramesRead = static_cast<int64_t>(mFifoBuffer->getReadCounter());
} // or else it will get updated by processBufferCallback()
}
// This is called by the OpenSL ES callback to read or write the back end of the FIFO.
DataCallbackResult AudioStreamBuffered::onDefaultCallback(void *audioData, int numFrames) {
int32_t framesTransferred = 0;
if (getDirection() == oboe::Direction::Output) {
// Read from the FIFO and write to audioData, clear part of buffer if not enough data.
framesTransferred = mFifoBuffer->readNow(audioData, numFrames);
} else {
// Read from audioData and write to the FIFO
framesTransferred = mFifoBuffer->write(audioData, numFrames); // There is no writeNow()
}
if (framesTransferred < numFrames) {
LOGD("AudioStreamBuffered::%s(): xrun! framesTransferred = %d, numFrames = %d",
__func__, framesTransferred, numFrames);
// TODO If we do not allow FIFO to wrap then our timestamps will drift when there is an XRun!
incrementXRunCount();
}
markCallbackTime(static_cast<int32_t>(numFrames)); // so foreground knows how long to wait.
return DataCallbackResult::Continue;
}
void AudioStreamBuffered::markCallbackTime(int32_t numFrames) {
mLastBackgroundSize = numFrames;
mBackgroundRanAtNanoseconds = AudioClock::getNanoseconds();
}
int64_t AudioStreamBuffered::predictNextCallbackTime() {
if (mBackgroundRanAtNanoseconds == 0) {
return 0;
}
int64_t nanosPerBuffer = (kNanosPerSecond * mLastBackgroundSize) / getSampleRate();
const int64_t margin = 200 * kNanosPerMicrosecond; // arbitrary delay so we wake up just after
return mBackgroundRanAtNanoseconds + nanosPerBuffer + margin;
}
// Common code for read/write.
// @return Result::OK with frames read/written, or Result::Error*
ResultWithValue<int32_t> AudioStreamBuffered::transfer(void *buffer,
int32_t numFrames,
int64_t timeoutNanoseconds) {
// Validate arguments.
if (buffer == nullptr) {
LOGE("AudioStreamBuffered::%s(): buffer is NULL", __func__);
return ResultWithValue<int32_t>(Result::ErrorNull);
}
if (numFrames < 0) {
LOGE("AudioStreamBuffered::%s(): numFrames is negative", __func__);
return ResultWithValue<int32_t>(Result::ErrorOutOfRange);
} else if (numFrames == 0) {
return ResultWithValue<int32_t>(numFrames);
}
if (timeoutNanoseconds < 0) {
LOGE("AudioStreamBuffered::%s(): timeoutNanoseconds is negative", __func__);
return ResultWithValue<int32_t>(Result::ErrorOutOfRange);
}
int32_t result = 0;
uint8_t *data = reinterpret_cast<uint8_t *>(buffer);
int32_t framesLeft = numFrames;
int64_t timeToQuit = 0;
bool repeat = true;
// Calculate when to timeout.
if (timeoutNanoseconds > 0) {
timeToQuit = AudioClock::getNanoseconds() + timeoutNanoseconds;
}
// Loop until we get the data, or we have an error, or we timeout.
do {
// read or write
if (getDirection() == Direction::Input) {
result = mFifoBuffer->read(data, framesLeft);
} else {
// between zero and capacity
uint32_t fullFrames = mFifoBuffer->getFullFramesAvailable();
// Do not write above threshold size.
int32_t emptyFrames = getBufferSizeInFrames() - static_cast<int32_t>(fullFrames);
int32_t framesToWrite = std::max(0, std::min(framesLeft, emptyFrames));
result = mFifoBuffer->write(data, framesToWrite);
}
if (result > 0) {
data += mFifoBuffer->convertFramesToBytes(result);
framesLeft -= result;
}
// If we need more data then sleep and try again.
if (framesLeft > 0 && result >= 0 && timeoutNanoseconds > 0) {
int64_t timeNow = AudioClock::getNanoseconds();
if (timeNow >= timeToQuit) {
LOGE("AudioStreamBuffered::%s(): TIMEOUT", __func__);
repeat = false; // TIMEOUT
} else {
// Figure out how long to sleep.
int64_t sleepForNanos;
int64_t wakeTimeNanos = predictNextCallbackTime();
if (wakeTimeNanos <= 0) {
// No estimate available. Sleep for one burst.
sleepForNanos = (getFramesPerBurst() * kNanosPerSecond) / getSampleRate();
} else {
// Don't sleep past timeout.
if (wakeTimeNanos > timeToQuit) {
wakeTimeNanos = timeToQuit;
}
sleepForNanos = wakeTimeNanos - timeNow;
// Avoid rapid loop with no sleep.
const int64_t minSleepTime = kNanosPerMillisecond; // arbitrary
if (sleepForNanos < minSleepTime) {
sleepForNanos = minSleepTime;
}
}
AudioClock::sleepForNanos(sleepForNanos);
}
} else {
repeat = false;
}
} while(repeat);
if (result < 0) {
return ResultWithValue<int32_t>(static_cast<Result>(result));
} else {
int32_t framesWritten = numFrames - framesLeft;
return ResultWithValue<int32_t>(framesWritten);
}
}
// Write to the FIFO so the callback can read from it.
ResultWithValue<int32_t> AudioStreamBuffered::write(const void *buffer,
int32_t numFrames,
int64_t timeoutNanoseconds) {
if (getState() == StreamState::Closed){
return ResultWithValue<int32_t>(Result::ErrorClosed);
}
if (getDirection() == Direction::Input) {
return ResultWithValue<int32_t>(Result::ErrorUnavailable); // TODO review, better error code?
}
updateServiceFrameCounter();
return transfer(const_cast<void *>(buffer), numFrames, timeoutNanoseconds);
}
// Read data from the FIFO that was written by the callback.
ResultWithValue<int32_t> AudioStreamBuffered::read(void *buffer,
int32_t numFrames,
int64_t timeoutNanoseconds) {
if (getState() == StreamState::Closed){
return ResultWithValue<int32_t>(Result::ErrorClosed);
}
if (getDirection() == Direction::Output) {
return ResultWithValue<int32_t>(Result::ErrorUnavailable); // TODO review, better error code?
}
updateServiceFrameCounter();
return transfer(buffer, numFrames, timeoutNanoseconds);
}
// Only supported when we are not using a callback.
ResultWithValue<int32_t> AudioStreamBuffered::setBufferSizeInFrames(int32_t requestedFrames)
{
if (getState() == StreamState::Closed){
return ResultWithValue<int32_t>(Result::ErrorClosed);
}
if (!mFifoBuffer) {
return ResultWithValue<int32_t>(Result::ErrorUnimplemented);
}
if (requestedFrames > mFifoBuffer->getBufferCapacityInFrames()) {
requestedFrames = mFifoBuffer->getBufferCapacityInFrames();
} else if (requestedFrames < getFramesPerBurst()) {
requestedFrames = getFramesPerBurst();
}
mBufferSizeInFrames = requestedFrames;
return ResultWithValue<int32_t>(requestedFrames);
}
int32_t AudioStreamBuffered::getBufferCapacityInFrames() const {
if (mFifoBuffer) {
return mFifoBuffer->getBufferCapacityInFrames();
} else {
return AudioStream::getBufferCapacityInFrames();
}
}
bool AudioStreamBuffered::isXRunCountSupported() const {
// XRun count is only supported if we're using blocking I/O (not callbacks)
return (getCallback() == nullptr);
}
} // namespace oboe