Merge "Correlation tool : Initial version"
diff --git a/media/libeffects/preprocessing/tests/Android.bp b/media/libeffects/preprocessing/tests/Android.bp
index b439880..5e8255a 100644
--- a/media/libeffects/preprocessing/tests/Android.bp
+++ b/media/libeffects/preprocessing/tests/Android.bp
@@ -19,3 +19,14 @@
"libhardware_headers",
],
}
+
+cc_test {
+ name: "correlation",
+ host_supported: true,
+ srcs: ["correlation.cpp"],
+ cflags: [
+ "-Wall",
+ "-Werror",
+ "-Wextra",
+ ],
+}
diff --git a/media/libeffects/preprocessing/tests/correlation.cpp b/media/libeffects/preprocessing/tests/correlation.cpp
new file mode 100644
index 0000000..b13dcc7
--- /dev/null
+++ b/media/libeffects/preprocessing/tests/correlation.cpp
@@ -0,0 +1,166 @@
+/*
+ * Copyright (C) 2021 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 <iostream>
+#include <vector>
+
+constexpr int kMinLoopLimitValue = 1;
+constexpr int kNumPeaks = 3;
+
+/*!
+ \brief Compute the length normalized correlation of two signals
+
+ \sigX Pointer to signal 1
+ \sigY Pointer to signal 2
+ \len Length of signals
+ \enableCrossCorr Flag to be set to 1 if cross-correlation is needed
+
+ \return First value is vector of correlation peak indices
+ Second value is vector of correlation peak values
+*/
+
+static std::pair<std::vector<int>, std::vector<float>> correlation(const int16_t* sigX,
+ const int16_t* sigY, int len,
+ int16_t enableCrossCorr) {
+ float maxCorrVal = 0.f, prevCorrVal = 0.f;
+ int delay = 0, peakIndex = 0, flag = 0;
+ int loopLim = (1 == enableCrossCorr) ? len : kMinLoopLimitValue;
+ std::vector<int> peakIndexVect(kNumPeaks, 0);
+ std::vector<float> peakValueVect(kNumPeaks, 0.f);
+ for (int i = 0; i < loopLim; i++) {
+ float corrVal = 0.f;
+ for (int j = i; j < len; j++) {
+ corrVal += (float)(sigX[j] * sigY[j - i]);
+ }
+ corrVal /= len - i;
+ if (corrVal > maxCorrVal) {
+ delay = i;
+ maxCorrVal = corrVal;
+ }
+ // Correlation peaks are expected to be observed at equal intervals. The interval length is
+ // expected to match with wave period.
+ // The following block of code saves the first kNumPeaks number of peaks and the index at
+ // which they occur.
+ if (peakIndex < kNumPeaks) {
+ if (corrVal > prevCorrVal) {
+ peakIndexVect[peakIndex] = i;
+ peakValueVect[peakIndex] = corrVal;
+ flag = 0;
+ } else if (0 == flag) {
+ peakIndex++;
+ flag = 1;
+ }
+ }
+ if (peakIndex == kNumPeaks) break;
+ prevCorrVal = corrVal;
+ }
+ return {peakIndexVect, peakValueVect};
+}
+
+void printUsage() {
+ printf("\nUsage: ");
+ printf("\n correlation <firstFile> <secondFile> [enableCrossCorr]\n");
+ printf("\nwhere, \n <firstFile> is the first file name");
+ printf("\n <secondFile> is the second file name");
+ printf("\n [enableCrossCorr] is flag to set for cross-correlation (Default 1)\n\n");
+}
+
+int main(int argc, const char* argv[]) {
+ if (argc < 3) {
+ printUsage();
+ return EXIT_FAILURE;
+ }
+
+ std::unique_ptr<FILE, decltype(&fclose)> fInput1(fopen(argv[1], "rb"), &fclose);
+ if (fInput1.get() == NULL) {
+ printf("\nError: missing file %s\n", argv[1]);
+ return EXIT_FAILURE;
+ }
+ std::unique_ptr<FILE, decltype(&fclose)> fInput2(fopen(argv[2], "rb"), &fclose);
+ if (fInput2.get() == NULL) {
+ printf("\nError: missing file %s\n", argv[2]);
+ return EXIT_FAILURE;
+ }
+ int16_t enableCrossCorr = (4 == argc) ? atoi(argv[3]) : 1;
+
+ fseek(fInput1.get(), 0L, SEEK_END);
+ unsigned int fileSize1 = ftell(fInput1.get());
+ rewind(fInput1.get());
+ fseek(fInput2.get(), 0L, SEEK_END);
+ unsigned int fileSize2 = ftell(fInput2.get());
+ rewind(fInput2.get());
+ if (fileSize1 != fileSize2) {
+ printf("\nError: File sizes different\n");
+ return EXIT_FAILURE;
+ }
+
+ int numFrames = fileSize1 / sizeof(int16_t);
+ std::unique_ptr<int16_t[]> inBuffer1(new int16_t[numFrames]());
+ std::unique_ptr<int16_t[]> inBuffer2(new int16_t[numFrames]());
+
+ fread(inBuffer1.get(), sizeof(int16_t), numFrames, fInput1.get());
+ fread(inBuffer2.get(), sizeof(int16_t), numFrames, fInput2.get());
+
+ auto pairAutoCorr1 = correlation(inBuffer1.get(), inBuffer1.get(), numFrames, enableCrossCorr);
+ auto pairAutoCorr2 = correlation(inBuffer2.get(), inBuffer2.get(), numFrames, enableCrossCorr);
+
+ // Following code block checks pitch period difference between two input signals. They must
+ // match as AGC applies only gain, no frequency related computation is done.
+ bool pitchMatch = false;
+ for (unsigned i = 0; i < pairAutoCorr1.first.size() - 1; i++) {
+ if (pairAutoCorr1.first[i + 1] - pairAutoCorr1.first[i] !=
+ pairAutoCorr2.first[i + 1] - pairAutoCorr2.first[i]) {
+ pitchMatch = false;
+ break;
+ }
+ pitchMatch = true;
+ }
+ if (pitchMatch) {
+ printf("Auto-correlation : Pitch matched\n");
+ } else {
+ printf("Auto-correlation : Pitch mismatch\n");
+ return EXIT_FAILURE;
+ }
+
+ if (enableCrossCorr) {
+ auto pairCrossCorr =
+ correlation(inBuffer1.get(), inBuffer2.get(), numFrames, enableCrossCorr);
+
+ // Since AGC applies only gain, the pitch information obtained from cross correlation data
+ // of input and output is expected to be same as the input signal's pitch information.
+ pitchMatch = false;
+ for (unsigned i = 0; i < pairCrossCorr.first.size() - 1; i++) {
+ if (pairAutoCorr1.first[i + 1] - pairAutoCorr1.first[i] !=
+ pairCrossCorr.first[i + 1] - pairCrossCorr.first[i]) {
+ pitchMatch = false;
+ break;
+ }
+ pitchMatch = true;
+ }
+ if (pitchMatch) {
+ printf("Cross-correlation : Pitch matched for AGC\n");
+ if (pairAutoCorr1.second[0]) {
+ printf("Expected gain : (maxCrossCorr / maxAutoCorr1) = %f\n",
+ pairCrossCorr.second[0] / pairAutoCorr1.second[0]);
+ }
+ } else {
+ printf("Cross-correlation : Pitch mismatch\n");
+ return EXIT_FAILURE;
+ }
+ }
+
+ return EXIT_SUCCESS;
+}