/*
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* Copyright 2017 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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// #define LOG_NDEBUG 0
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#define LOG_TAG "audio_utils_power"
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#include <log/log.h>
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#include <algorithm>
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#include <math.h>
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#include <audio_utils/power.h>
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#include <audio_utils/primitives.h>
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#if defined(__aarch64__) || defined(__ARM_NEON__)
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#include <arm_neon.h>
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#define USE_NEON
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#endif
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namespace {
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constexpr inline bool isFormatSupported(audio_format_t format) {
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switch (format) {
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case AUDIO_FORMAT_PCM_8_BIT:
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case AUDIO_FORMAT_PCM_16_BIT:
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case AUDIO_FORMAT_PCM_24_BIT_PACKED:
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case AUDIO_FORMAT_PCM_8_24_BIT:
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case AUDIO_FORMAT_PCM_32_BIT:
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case AUDIO_FORMAT_PCM_FLOAT:
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return true;
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default:
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return false;
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}
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}
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template <typename T>
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inline T getPtrPtrValueAndIncrement(const void **data)
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{
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return *(*reinterpret_cast<const T **>(data))++;
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}
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template <audio_format_t FORMAT>
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inline float convertToFloatAndIncrement(const void **data)
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{
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switch (FORMAT) {
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case AUDIO_FORMAT_PCM_8_BIT:
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return float_from_u8(getPtrPtrValueAndIncrement<uint8_t>(data));
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case AUDIO_FORMAT_PCM_16_BIT:
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return float_from_i16(getPtrPtrValueAndIncrement<int16_t>(data));
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case AUDIO_FORMAT_PCM_24_BIT_PACKED: {
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const uint8_t *uptr = reinterpret_cast<const uint8_t *>(*data);
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*data = uptr + 3;
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return float_from_p24(uptr);
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}
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case AUDIO_FORMAT_PCM_8_24_BIT:
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return float_from_q8_23(getPtrPtrValueAndIncrement<int32_t>(data));
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case AUDIO_FORMAT_PCM_32_BIT:
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return float_from_i32(getPtrPtrValueAndIncrement<int32_t>(data));
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case AUDIO_FORMAT_PCM_FLOAT:
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return getPtrPtrValueAndIncrement<float>(data);
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default:
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// static_assert cannot use false because the compiler may interpret it
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// even though this code path may never be taken.
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static_assert(isFormatSupported(FORMAT), "unsupported format");
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}
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}
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// used to normalize integer fixed point value to the floating point equivalent.
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template <audio_format_t FORMAT>
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constexpr inline float normalizeAmplitude()
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{
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switch (FORMAT) {
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case AUDIO_FORMAT_PCM_8_BIT:
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return 1.f / (1 << 7);
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case AUDIO_FORMAT_PCM_16_BIT:
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return 1.f / (1 << 15);
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case AUDIO_FORMAT_PCM_24_BIT_PACKED: // fall through
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case AUDIO_FORMAT_PCM_8_24_BIT:
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return 1.f / (1 << 23);
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case AUDIO_FORMAT_PCM_32_BIT:
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return 1.f / (1U << 31);
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case AUDIO_FORMAT_PCM_FLOAT:
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return 1.f;
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default:
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// static_assert cannot use false because the compiler may interpret it
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// even though this code path may never be taken.
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static_assert(isFormatSupported(FORMAT), "unsupported format");
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}
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}
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template <audio_format_t FORMAT>
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constexpr inline float normalizeEnergy()
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{
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const float val = normalizeAmplitude<FORMAT>();
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return val * val;
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}
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template <audio_format_t FORMAT>
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inline float energyMonoRef(const void *amplitudes, size_t size)
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{
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float accum(0.f);
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for (size_t i = 0; i < size; ++i) {
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const float amplitude = convertToFloatAndIncrement<FORMAT>(&litudes);
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accum += amplitude * amplitude;
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}
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return accum;
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}
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template <audio_format_t FORMAT>
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inline float energyMono(const void *amplitudes, size_t size)
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{
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return energyMonoRef<FORMAT>(amplitudes, size);
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}
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// fast float power computation for ARM processors that support NEON.
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#ifdef USE_NEON
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template <typename T>
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float32x4_t convertToFloatVectorAmplitude(T vamplitude) = delete;
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template <>
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float32x4_t convertToFloatVectorAmplitude<float32x4_t>(float32x4_t vamplitude) {
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return vamplitude;
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}
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template <>
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float32x4_t convertToFloatVectorAmplitude<int16x4_t>(int16x4_t vamplitude) {
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const int32x4_t iamplitude = vmovl_s16(vamplitude); // expand s16 to s32 first
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return vcvtq_f32_s32(iamplitude);
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}
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template <>
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float32x4_t convertToFloatVectorAmplitude<int32x4_t>(int32x4_t vamplitude) {
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return vcvtq_f32_s32(vamplitude);
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}
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template <typename Vector, typename Scalar>
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inline float energyMonoVector(const void *amplitudes, size_t size)
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{
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static_assert(sizeof(Vector) % sizeof(Scalar) == 0,
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"Vector size must be a multiple of scalar size");
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const size_t vectorLength = sizeof(Vector) / sizeof(Scalar); // typically 4 (a const)
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// check pointer validity, must be aligned with scalar type.
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const Scalar *samplitudes = reinterpret_cast<const Scalar *>(amplitudes);
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LOG_ALWAYS_FATAL_IF((uintptr_t)samplitudes % alignof(Scalar) != 0,
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"Non-element aligned address: %p %zu", samplitudes, alignof(Scalar));
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float accumulator = 0;
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// handle pointer unaligned to vector type.
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while ((uintptr_t)samplitudes % alignof(Vector) != 0 /* compiler optimized */ && size > 0) {
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const float amp = (float)*samplitudes++;
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accumulator += amp * amp;
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--size;
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}
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// samplitudes is now adjusted for proper vector alignment, cast to Vector *
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const Vector *vamplitudes = reinterpret_cast<const Vector *>(samplitudes);
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// clear vector accumulator
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float32x4_t accum = vdupq_n_f32(0);
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// iterate over array getting sum of squares in vectorLength lanes.
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size_t i;
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for (i = 0; i < size - size % vectorLength /* compiler optimized */; i += vectorLength) {
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const float32x4_t famplitude = convertToFloatVectorAmplitude(*vamplitudes++);
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accum = vmlaq_f32(accum, famplitude, famplitude);
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}
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// narrow vectorLength lanes of floats
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float32x2_t accum2 = vadd_f32(vget_low_f32(accum), vget_high_f32(accum)); // get stereo volume
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accum2 = vpadd_f32(accum2, accum2); // combine to mono
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// accumulate vector
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accumulator += vget_lane_f32(accum2, 0);
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// accumulate any trailing elements too small for vector size
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for (; i < size; ++i) {
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const float amp = (float)samplitudes[i];
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accumulator += amp * amp;
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}
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return accumulator;
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}
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template <>
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inline float energyMono<AUDIO_FORMAT_PCM_FLOAT>(const void *amplitudes, size_t size)
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{
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return energyMonoVector<float32x4_t, float>(amplitudes, size);
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}
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template <>
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inline float energyMono<AUDIO_FORMAT_PCM_16_BIT>(const void *amplitudes, size_t size)
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{
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return energyMonoVector<int16x4_t, int16_t>(amplitudes, size)
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* normalizeEnergy<AUDIO_FORMAT_PCM_16_BIT>();
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}
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// fast int32_t power computation for PCM_32
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template <>
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inline float energyMono<AUDIO_FORMAT_PCM_32_BIT>(const void *amplitudes, size_t size)
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{
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return energyMonoVector<int32x4_t, int32_t>(amplitudes, size)
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* normalizeEnergy<AUDIO_FORMAT_PCM_32_BIT>();
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}
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// fast int32_t power computation for PCM_8_24 (essentially identical to PCM_32 above)
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template <>
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inline float energyMono<AUDIO_FORMAT_PCM_8_24_BIT>(const void *amplitudes, size_t size)
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{
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return energyMonoVector<int32x4_t, int32_t>(amplitudes, size)
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* normalizeEnergy<AUDIO_FORMAT_PCM_8_24_BIT>();
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}
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#endif // USE_NEON
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} // namespace
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float audio_utils_compute_energy_mono(const void *buffer, audio_format_t format, size_t samples)
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{
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switch (format) {
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case AUDIO_FORMAT_PCM_8_BIT:
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return energyMono<AUDIO_FORMAT_PCM_8_BIT>(buffer, samples);
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case AUDIO_FORMAT_PCM_16_BIT:
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return energyMono<AUDIO_FORMAT_PCM_16_BIT>(buffer, samples);
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case AUDIO_FORMAT_PCM_24_BIT_PACKED:
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return energyMono<AUDIO_FORMAT_PCM_24_BIT_PACKED>(buffer, samples);
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case AUDIO_FORMAT_PCM_8_24_BIT:
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return energyMono<AUDIO_FORMAT_PCM_8_24_BIT>(buffer, samples);
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case AUDIO_FORMAT_PCM_32_BIT:
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return energyMono<AUDIO_FORMAT_PCM_32_BIT>(buffer, samples);
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case AUDIO_FORMAT_PCM_FLOAT:
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return energyMono<AUDIO_FORMAT_PCM_FLOAT>(buffer, samples);
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default:
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LOG_ALWAYS_FATAL("invalid format: %#x", format);
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}
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}
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float audio_utils_compute_power_mono(const void *buffer, audio_format_t format, size_t samples)
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{
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return audio_utils_power_from_energy(
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audio_utils_compute_energy_mono(buffer, format, samples) / samples);
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}
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bool audio_utils_is_compute_power_format_supported(audio_format_t format)
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{
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return isFormatSupported(format);
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}
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