AudioMixer: Preserve stereo volume in multi-channel mixing

CrOS exposes 4-channel output for ARC++ and mixes samples in CRAS
server to real channel format, but AudioMixer will discard right
channel volume when mixing a 2-channel track to 4-channel output.
This behavior will cause ARC++ fail on Audio Frequency Line Test
in CTS-V since the right channel can't be tested.

The code is also updated to work for 3, 5, 6, 7, 8 canonical output
channel position masks, as well as continue the mono volume
handling for output channel index masks.

Bug: 110551766
Test: Run CTS-V Audio Frequency Line Test
Test: atest mixerops_benchmark
Change-Id: I4c6ee86d30bb8296f0e32f9a17b1135e1313fd64
diff --git a/media/libaudioprocessing/tests/Android.bp b/media/libaudioprocessing/tests/Android.bp
index 20c2c2c..18acef7 100644
--- a/media/libaudioprocessing/tests/Android.bp
+++ b/media/libaudioprocessing/tests/Android.bp
@@ -55,3 +55,26 @@
     srcs: ["test-resampler.cpp"],
     static_libs: ["libsndfile"],
 }
+
+//
+// build mixerops objdump
+//
+// This is used to verify proper optimization of the code.
+//
+// For example, use:
+// ./prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9/bin/aarch64-linux-android-objdump
+//      -d --source ./out/target/product/crosshatch/symbols/system/bin/mixerops_objdump
+//
+cc_binary {
+    name: "mixerops_objdump",
+    srcs: ["mixerops_objdump.cpp"],
+}
+
+//
+// build mixerops benchmark
+//
+cc_benchmark {
+    name: "mixerops_benchmark",
+    srcs: ["mixerops_benchmark.cpp"],
+    static_libs: ["libgoogle-benchmark"],
+}
diff --git a/media/libaudioprocessing/tests/mixerops_benchmark.cpp b/media/libaudioprocessing/tests/mixerops_benchmark.cpp
new file mode 100644
index 0000000..86f5429
--- /dev/null
+++ b/media/libaudioprocessing/tests/mixerops_benchmark.cpp
@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2020 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 <inttypes.h>
+#include <type_traits>
+#include "../../../../system/media/audio_utils/include/audio_utils/primitives.h"
+#define LOG_ALWAYS_FATAL(...)
+
+#include <../AudioMixerOps.h>
+
+#include <benchmark/benchmark.h>
+
+using namespace android;
+
+template <int MIXTYPE, int NCHAN>
+static void BM_VolumeRampMulti(benchmark::State& state) {
+    constexpr size_t FRAME_COUNT = 1000;
+    constexpr size_t SAMPLE_COUNT = FRAME_COUNT * NCHAN;
+
+    // data inialized to 0.
+    float out[SAMPLE_COUNT]{};
+    float in[SAMPLE_COUNT]{};
+    float aux[FRAME_COUNT]{};
+
+    // volume initialized to 0
+    float vola = 0.f;
+    float vol[2] = {0.f, 0.f};
+
+    // some volume increment
+    float volainc = 0.01f;
+    float volinc[2] = {0.01f, 0.01f};
+
+    while (state.KeepRunning()) {
+        benchmark::DoNotOptimize(out);
+        benchmark::DoNotOptimize(in);
+        volumeRampMulti<MIXTYPE, NCHAN>(out, FRAME_COUNT, in, aux, vol, volinc, &vola, volainc);
+        benchmark::ClobberMemory();
+    }
+}
+
+template <int MIXTYPE, int NCHAN>
+static void BM_VolumeMulti(benchmark::State& state) {
+    constexpr size_t FRAME_COUNT = 1000;
+    constexpr size_t SAMPLE_COUNT = FRAME_COUNT * NCHAN;
+
+    // data inialized to 0.
+    float out[SAMPLE_COUNT]{};
+    float in[SAMPLE_COUNT]{};
+    float aux[FRAME_COUNT]{};
+
+    // volume initialized to 0
+    float vola = 0.f;
+    float vol[2] = {0.f, 0.f};
+
+
+    while (state.KeepRunning()) {
+        benchmark::DoNotOptimize(out);
+        benchmark::DoNotOptimize(in);
+        volumeMulti<MIXTYPE, NCHAN>(out, FRAME_COUNT, in, aux, vol, vola);
+        benchmark::ClobberMemory();
+    }
+}
+
+BENCHMARK_TEMPLATE(BM_VolumeRampMulti, MIXTYPE_MULTI, 2);
+BENCHMARK_TEMPLATE(BM_VolumeRampMulti, MIXTYPE_MULTI_SAVEONLY, 2);
+BENCHMARK_TEMPLATE(BM_VolumeRampMulti, MIXTYPE_MULTI_STEREOVOL, 2);
+BENCHMARK_TEMPLATE(BM_VolumeRampMulti, MIXTYPE_MULTI_SAVEONLY_STEREOVOL, 2);
+
+BENCHMARK_TEMPLATE(BM_VolumeRampMulti, MIXTYPE_MULTI, 4);
+BENCHMARK_TEMPLATE(BM_VolumeRampMulti, MIXTYPE_MULTI_SAVEONLY, 4);
+BENCHMARK_TEMPLATE(BM_VolumeRampMulti, MIXTYPE_MULTI_STEREOVOL, 4);
+BENCHMARK_TEMPLATE(BM_VolumeRampMulti, MIXTYPE_MULTI_SAVEONLY_STEREOVOL, 4);
+
+BENCHMARK_TEMPLATE(BM_VolumeRampMulti, MIXTYPE_MULTI, 5);
+BENCHMARK_TEMPLATE(BM_VolumeRampMulti, MIXTYPE_MULTI_SAVEONLY, 5);
+BENCHMARK_TEMPLATE(BM_VolumeRampMulti, MIXTYPE_MULTI_STEREOVOL, 5);
+BENCHMARK_TEMPLATE(BM_VolumeRampMulti, MIXTYPE_MULTI_SAVEONLY_STEREOVOL, 5);
+
+BENCHMARK_TEMPLATE(BM_VolumeRampMulti, MIXTYPE_MULTI, 8);
+BENCHMARK_TEMPLATE(BM_VolumeRampMulti, MIXTYPE_MULTI_SAVEONLY, 8);
+BENCHMARK_TEMPLATE(BM_VolumeRampMulti, MIXTYPE_MULTI_STEREOVOL, 8);
+BENCHMARK_TEMPLATE(BM_VolumeRampMulti, MIXTYPE_MULTI_SAVEONLY_STEREOVOL, 8);
+
+BENCHMARK_TEMPLATE(BM_VolumeMulti, MIXTYPE_MULTI, 8);
+BENCHMARK_TEMPLATE(BM_VolumeMulti, MIXTYPE_MULTI_SAVEONLY, 8);
+BENCHMARK_TEMPLATE(BM_VolumeMulti, MIXTYPE_MULTI_STEREOVOL, 8);
+BENCHMARK_TEMPLATE(BM_VolumeMulti, MIXTYPE_MULTI_SAVEONLY_STEREOVOL, 8);
+
+BENCHMARK_MAIN();
diff --git a/media/libaudioprocessing/tests/mixerops_objdump.cpp b/media/libaudioprocessing/tests/mixerops_objdump.cpp
new file mode 100644
index 0000000..ee7e837
--- /dev/null
+++ b/media/libaudioprocessing/tests/mixerops_objdump.cpp
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2020 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 <inttypes.h>
+#include <type_traits>
+#include "../../../../system/media/audio_utils/include/audio_utils/primitives.h"
+#define LOG_ALWAYS_FATAL(...)
+
+#include <../AudioMixerOps.h>
+
+using namespace android;
+
+template <int MIXTYPE, int NCHAN>
+static void checkVolumeRampMulti() {
+    constexpr size_t FRAME_COUNT = 1000;
+    constexpr size_t SAMPLE_COUNT = FRAME_COUNT * NCHAN;
+
+    // data inialized to 0.
+    float out[SAMPLE_COUNT]{};
+    float in[SAMPLE_COUNT]{};
+    float aux[FRAME_COUNT]{};
+
+    // volume initialized to 0
+    float vola = 0.f;
+    float vol[2] = {0.f, 0.f};
+
+    // some volume increment
+    float volainc = 0.01f;
+    float volinc[2] = {0.01f, 0.01f};
+
+    // try the multi ramp code.
+    volumeRampMulti<MIXTYPE, NCHAN>(out, FRAME_COUNT, in, aux, vol, volinc, &vola, volainc);
+}
+
+// Use this to check the objdump to ensure reasonable code.
+int main() {
+    checkVolumeRampMulti<MIXTYPE_MULTI_STEREOVOL, 5>();
+    return EXIT_SUCCESS;
+}