First submission of audio effect library from NXP software.

This CL contains the first open sourceable version of the audio effect library from NXP software.
The effects implemented are:
- Bass boost
- Virtualizer (stereo widening)
- Equalizer
- Spectrum analyzer

Source file for the effect engines are located under libeffects/lvm/lib
The wrapper implementing the interface with the audio effect framework in under libeffects/lvm/wrapper

The code of other effect libraries has also been reorganized fo clarity:
- the effect factory is now under libeffects/factory
- the test equalizer and reverb effects are under libeffect/testlibs
- the visualizer is under libeffects/virtualizer

Change-Id: I8d91e2181f81b89f8fc0c1e1e6bf552c5809b2eb

1 files changed, 109 insertions, 0 deletions

diff --git a/media/libeffects/testlibs/AudioShelvingFilter.cpp b/media/libeffects/testlibs/AudioShelvingFilter.cpp
new file mode 100644
index 0000000..b8650ba
--- /dev/null
+++ b/media/libeffects/testlibs/AudioShelvingFilter.cpp
@@ -0,0 +1,109 @@
+/* /android/src/frameworks/base/libs/audioflinger/AudioShelvingFilter.cpp
+**
+** Copyright 2009, 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 "AudioShelvingFilter.h"
+#include "AudioCommon.h"
+#include "EffectsMath.h"
+
+#include <new>
+#include <assert.h>
+
+#define LIKELY( exp )       (__builtin_expect( (exp) != 0, true  ))
+#define UNLIKELY( exp )     (__builtin_expect( (exp) != 0, false ))
+
+namespace android {
+// Format of the coefficient tables:
+// kCoefTable[freq][gain][coef]
+// freq  - cutoff frequency, in octaves below Nyquist,from -10 to -6 in low
+//         shelf, -2 to 0 in high shelf.
+// gain  - gain, in millibel, starting at -9600, jumps of 1024, to 4736 millibel.
+// coef - 0: b0
+//        1: b1
+//        2: b2
+//        3: -a1
+//        4: -a2
+static const size_t kHiInDims[2] = {3, 15};
+static const audio_coef_t kHiCoefTable[3*15*5] = {
+#include "AudioHighShelfFilterCoef.inl"
+};
+static const size_t kLoInDims[2] = {5, 15};
+static const audio_coef_t kLoCoefTable[5*15*5] = {
+#include "AudioLowShelfFilterCoef.inl"
+};
+
+AudioCoefInterpolator AudioShelvingFilter::mHiCoefInterp(2, kHiInDims, 5, (const audio_coef_t*) kHiCoefTable);
+AudioCoefInterpolator AudioShelvingFilter::mLoCoefInterp(2, kLoInDims, 5, (const audio_coef_t*) kLoCoefTable);
+
+AudioShelvingFilter::AudioShelvingFilter(ShelfType type, int nChannels,
+                                         int sampleRate)
+        : mType(type),
+          mBiquad(nChannels, sampleRate)  {
+    configure(nChannels, sampleRate);
+}
+
+void AudioShelvingFilter::configure(int nChannels, int sampleRate) {
+    mNiquistFreq = sampleRate * 500;
+    mFrequencyFactor = ((1ull) << 42) / mNiquistFreq;
+    mBiquad.configure(nChannels, sampleRate);
+    setFrequency(mNominalFrequency);
+    commit(true);
+}
+
+void AudioShelvingFilter::reset() {
+    setGain(0);
+    setFrequency(mType == kLowShelf ? 0 : mNiquistFreq);
+    commit(true);
+}
+
+void AudioShelvingFilter::setFrequency(uint32_t millihertz) {
+    mNominalFrequency = millihertz;
+    if (UNLIKELY(millihertz > mNiquistFreq / 2)) {
+        millihertz = mNiquistFreq / 2;
+    }
+    uint32_t normFreq = static_cast<uint32_t>(
+            (static_cast<uint64_t>(millihertz) * mFrequencyFactor) >> 10);
+    uint32_t log2minFreq = (mType == kLowShelf ? (32-10) : (32-2));
+    if (LIKELY(normFreq > (1U << log2minFreq))) {
+        mFrequency = (Effects_log2(normFreq) - (log2minFreq << 15)) << (FREQ_PRECISION_BITS - 15);
+    } else {
+        mFrequency = 0;
+    }
+}
+
+void AudioShelvingFilter::setGain(int32_t millibel) {
+    mGain = millibel + 9600;
+}
+
+void AudioShelvingFilter::commit(bool immediate) {
+    audio_coef_t coefs[5];
+    int intCoord[2] = {
+        mFrequency >> FREQ_PRECISION_BITS,
+        mGain >> GAIN_PRECISION_BITS
+    };
+    uint32_t fracCoord[2] = {
+        mFrequency << (32 - FREQ_PRECISION_BITS),
+        static_cast<uint32_t>(mGain) << (32 - GAIN_PRECISION_BITS)
+    };
+    if (mType == kHighShelf) {
+        mHiCoefInterp.getCoef(intCoord, fracCoord, coefs);
+    } else {
+        mLoCoefInterp.getCoef(intCoord, fracCoord, coefs);
+    }
+    mBiquad.setCoefs(coefs, immediate);
+}
+
+}