Effect AIDL Add visualizer libeffect implementation

Bug: 258124419
Test: atest VtsHalVisualizerTargetTest
Change-Id: I051865bb8eba64a7e3624899d9018ba4eed53ac0
diff --git a/media/libeffects/visualizer/aidl/VisualizerContext.h b/media/libeffects/visualizer/aidl/VisualizerContext.h
new file mode 100644
index 0000000..26db0b1
--- /dev/null
+++ b/media/libeffects/visualizer/aidl/VisualizerContext.h
@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2022 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.
+ */
+
+#pragma once
+
+#include <android-base/thread_annotations.h>
+#include <audio_effects/effect_dynamicsprocessing.h>
+
+#include "effect-impl/EffectContext.h"
+
+namespace aidl::android::hardware::audio::effect {
+
+class VisualizerContext final : public EffectContext {
+  public:
+    static const uint32_t kMaxCaptureBufSize = 65536;
+    static const uint32_t kMaxLatencyMs = 3000;  // 3 seconds of latency for audio pipeline
+
+    VisualizerContext(int statusDepth, const Parameter::Common& common);
+    ~VisualizerContext();
+
+    RetCode initParams(const Parameter::Common& common);
+
+    RetCode enable();
+    RetCode disable();
+    // keep all parameters and reset buffer.
+    void reset();
+
+    RetCode setCaptureSamples(int captureSize);
+    int getCaptureSamples();
+    RetCode setMeasurementMode(Visualizer::MeasurementMode mode);
+    Visualizer::MeasurementMode getMeasurementMode();
+    RetCode setScalingMode(Visualizer::ScalingMode mode);
+    Visualizer::ScalingMode getScalingMode();
+    RetCode setDownstreamLatency(int latency);
+
+    IEffect::Status process(float* in, float* out, int samples);
+    // Gets the current measurements, measured by process() and consumed by getParameter()
+    Visualizer::GetOnlyParameters::Measurement getMeasure();
+    // Gets the latest PCM capture, data captured by process() and consumed by getParameter()
+    std::vector<uint8_t> capture();
+
+    struct BufferStats {
+        bool mIsValid;
+        uint16_t mPeakU16; // the positive peak of the absolute value of the samples in a buffer
+        float mRmsSquared; // the average square of the samples in a buffer
+    };
+
+    enum State {
+        UNINITIALIZED,
+        INITIALIZED,
+        ACTIVE,
+    };
+
+  private:
+    // maximum time since last capture buffer update before resetting capture buffer. This means
+    // that the framework has stopped playing audio and we must start returning silence
+    static const uint32_t kMaxStallTimeMs = 1000;
+    // discard measurements older than this number of ms
+    static const uint32_t kDiscardMeasurementsTimeMs = 2000;
+    // maximum number of buffers for which we keep track of the measurements
+    // note: buffer index is stored in uint8_t
+    static const uint32_t kMeasurementWindowMaxSizeInBuffers = 25;
+
+    // serialize process() and parameter setting
+    std::mutex mMutex;
+    Parameter::Common mCommon GUARDED_BY(mMutex);
+    State mState GUARDED_BY(mMutex) = State::UNINITIALIZED;
+    uint32_t mCaptureIdx GUARDED_BY(mMutex);
+    uint32_t mLastCaptureIdx GUARDED_BY(mMutex);
+    Visualizer::ScalingMode mScalingMode GUARDED_BY(mMutex) = Visualizer::ScalingMode::NORMALIZED;
+    struct timespec mBufferUpdateTime GUARDED_BY(mMutex);
+    // capture buf with 8 bits PCM
+    std::array<uint8_t, kMaxCaptureBufSize> mCaptureBuf GUARDED_BY(mMutex);
+    // no mutex, only accessed by parameters
+    uint32_t mDownstreamLatency;
+    uint32_t mCaptureSamples = kMaxCaptureBufSize;
+
+    // to avoid recomputing it every time a buffer is processed
+    uint8_t mChannelCount GUARDED_BY(mMutex);
+    Visualizer::MeasurementMode mMeasurementMode GUARDED_BY(mMutex) =
+            Visualizer::MeasurementMode::NONE;
+    uint8_t mMeasurementWindowSizeInBuffers = kMeasurementWindowMaxSizeInBuffers;
+    uint8_t mMeasurementBufferIdx GUARDED_BY(mMutex);
+    std::array<BufferStats, kMeasurementWindowMaxSizeInBuffers> mPastMeasurements;
+    void init_params();
+
+    uint32_t getDeltaTimeMsFromUpdatedTime_l() REQUIRES(mMutex);
+};
+}  // namespace aidl::android::hardware::audio::effect