aaudio: add simple flowgraph system
Implement a simple data flow model that can be used to
chain various processing modules including:
data format conversion
volume ramping
channel conversion
Bug: 65067568
Test: test_flowgraph.cpp
Change-Id: I81a5655406cfa8c1c7d7cef4d933879f823939a5
diff --git a/media/libaaudio/src/flowgraph/RampLinear.cpp b/media/libaaudio/src/flowgraph/RampLinear.cpp
new file mode 100644
index 0000000..a260828
--- /dev/null
+++ b/media/libaaudio/src/flowgraph/RampLinear.cpp
@@ -0,0 +1,85 @@
+/*
+ * Copyright 2015 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.
+ */
+
+#define LOG_TAG "RampLinear"
+//#define LOG_NDEBUG 0
+#include <utils/Log.h>
+
+#include <algorithm>
+#include <unistd.h>
+#include "AudioProcessorBase.h"
+#include "RampLinear.h"
+
+using namespace flowgraph;
+
+RampLinear::RampLinear(int32_t channelCount)
+ : input(*this, channelCount)
+ , output(*this, channelCount) {
+ mTarget.store(1.0f);
+}
+
+void RampLinear::setLengthInFrames(int32_t frames) {
+ mLengthInFrames = frames;
+}
+
+void RampLinear::setTarget(float target) {
+ mTarget.store(target);
+}
+
+float RampLinear::interpolateCurrent() {
+ return mLevelTo - (mRemaining * mScaler);
+}
+
+int32_t RampLinear::onProcess(int64_t framePosition, int32_t numFrames) {
+ int32_t framesToProcess = input.pullData(framePosition, numFrames);
+ const float *inputBuffer = input.getBlock();
+ float *outputBuffer = output.getBlock();
+ int32_t channelCount = output.getSamplesPerFrame();
+
+ float target = getTarget();
+ if (target != mLevelTo) {
+ // Start new ramp. Continue from previous level.
+ mLevelFrom = interpolateCurrent();
+ mLevelTo = target;
+ mRemaining = mLengthInFrames;
+ ALOGV("%s() mLevelFrom = %f, mLevelTo = %f, mRemaining = %d, mScaler = %f",
+ __func__, mLevelFrom, mLevelTo, mRemaining, mScaler);
+ mScaler = (mLevelTo - mLevelFrom) / mLengthInFrames; // for interpolation
+ }
+
+ int32_t framesLeft = framesToProcess;
+
+ if (mRemaining > 0) { // Ramping? This doesn't happen very often.
+ int32_t framesToRamp = std::min(framesLeft, mRemaining);
+ framesLeft -= framesToRamp;
+ while (framesToRamp > 0) {
+ float currentLevel = interpolateCurrent();
+ for (int ch = 0; ch < channelCount; ch++) {
+ *outputBuffer++ = *inputBuffer++ * currentLevel;
+ }
+ mRemaining--;
+ framesToRamp--;
+ }
+ }
+
+ // Process any frames after the ramp.
+ int32_t samplesLeft = framesLeft * channelCount;
+ for (int i = 0; i < samplesLeft; i++) {
+ *outputBuffer++ = *inputBuffer++ * mLevelTo;
+ }
+
+ return framesToProcess;
+}