/*
* Copyright 2017 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.
*/
// #define LOG_NDEBUG 0
#define LOG_TAG "audio_utils_power"
#include <log/log.h>
#include <algorithm>
#include <math.h>
#include <audio_utils/power.h>
#include <audio_utils/primitives.h>
#if defined(__aarch64__) || defined(__ARM_NEON__)
#include <arm_neon.h>
#define USE_NEON
#endif
namespace {
constexpr inline bool isFormatSupported(audio_format_t format) {
switch (format) {
case AUDIO_FORMAT_PCM_8_BIT:
case AUDIO_FORMAT_PCM_16_BIT:
case AUDIO_FORMAT_PCM_24_BIT_PACKED:
case AUDIO_FORMAT_PCM_8_24_BIT:
case AUDIO_FORMAT_PCM_32_BIT:
case AUDIO_FORMAT_PCM_FLOAT:
return true;
default:
return false;
}
}
template <typename T>
inline T getPtrPtrValueAndIncrement(const void **data)
{
return *(*reinterpret_cast<const T **>(data))++;
}
template <audio_format_t FORMAT>
inline float convertToFloatAndIncrement(const void **data)
{
switch (FORMAT) {
case AUDIO_FORMAT_PCM_8_BIT:
return float_from_u8(getPtrPtrValueAndIncrement<uint8_t>(data));
case AUDIO_FORMAT_PCM_16_BIT:
return float_from_i16(getPtrPtrValueAndIncrement<int16_t>(data));
case AUDIO_FORMAT_PCM_24_BIT_PACKED: {
const uint8_t *uptr = reinterpret_cast<const uint8_t *>(*data);
*data = uptr + 3;
return float_from_p24(uptr);
}
case AUDIO_FORMAT_PCM_8_24_BIT:
return float_from_q8_23(getPtrPtrValueAndIncrement<int32_t>(data));
case AUDIO_FORMAT_PCM_32_BIT:
return float_from_i32(getPtrPtrValueAndIncrement<int32_t>(data));
case AUDIO_FORMAT_PCM_FLOAT:
return getPtrPtrValueAndIncrement<float>(data);
default:
// static_assert cannot use false because the compiler may interpret it
// even though this code path may never be taken.
static_assert(isFormatSupported(FORMAT), "unsupported format");
}
}
// used to normalize integer fixed point value to the floating point equivalent.
template <audio_format_t FORMAT>
constexpr inline float normalizeAmplitude()
{
switch (FORMAT) {
case AUDIO_FORMAT_PCM_8_BIT:
return 1.f / (1 << 7);
case AUDIO_FORMAT_PCM_16_BIT:
return 1.f / (1 << 15);
case AUDIO_FORMAT_PCM_24_BIT_PACKED: // fall through
case AUDIO_FORMAT_PCM_8_24_BIT:
return 1.f / (1 << 23);
case AUDIO_FORMAT_PCM_32_BIT:
return 1.f / (1U << 31);
case AUDIO_FORMAT_PCM_FLOAT:
return 1.f;
default:
// static_assert cannot use false because the compiler may interpret it
// even though this code path may never be taken.
static_assert(isFormatSupported(FORMAT), "unsupported format");
}
}
template <audio_format_t FORMAT>
constexpr inline float normalizeEnergy()
{
const float val = normalizeAmplitude<FORMAT>();
return val * val;
}
template <audio_format_t FORMAT>
inline float energyMonoRef(const void *amplitudes, size_t size)
{
float accum(0.f);
for (size_t i = 0; i < size; ++i) {
const float amplitude = convertToFloatAndIncrement<FORMAT>(&litudes);
accum += amplitude * amplitude;
}
return accum;
}
template <audio_format_t FORMAT>
inline float energyMono(const void *amplitudes, size_t size)
{
return energyMonoRef<FORMAT>(amplitudes, size);
}
// fast float power computation for ARM processors that support NEON.
#ifdef USE_NEON
template <typename T>
float32x4_t convertToFloatVectorAmplitude(T vamplitude) = delete;
template <>
float32x4_t convertToFloatVectorAmplitude<float32x4_t>(float32x4_t vamplitude) {
return vamplitude;
}
template <>
float32x4_t convertToFloatVectorAmplitude<int16x4_t>(int16x4_t vamplitude) {
const int32x4_t iamplitude = vmovl_s16(vamplitude); // expand s16 to s32 first
return vcvtq_f32_s32(iamplitude);
}
template <>
float32x4_t convertToFloatVectorAmplitude<int32x4_t>(int32x4_t vamplitude) {
return vcvtq_f32_s32(vamplitude);
}
template <typename Vector, typename Scalar>
inline float energyMonoVector(const void *amplitudes, size_t size)
{
static_assert(sizeof(Vector) % sizeof(Scalar) == 0,
"Vector size must be a multiple of scalar size");
const size_t vectorLength = sizeof(Vector) / sizeof(Scalar); // typically 4 (a const)
// check pointer validity, must be aligned with scalar type.
const Scalar *samplitudes = reinterpret_cast<const Scalar *>(amplitudes);
LOG_ALWAYS_FATAL_IF((uintptr_t)samplitudes % alignof(Scalar) != 0,
"Non-element aligned address: %p %zu", samplitudes, alignof(Scalar));
float accumulator = 0;
// handle pointer unaligned to vector type.
while ((uintptr_t)samplitudes % alignof(Vector) != 0 /* compiler optimized */ && size > 0) {
const float amp = (float)*samplitudes++;
accumulator += amp * amp;
--size;
}
// samplitudes is now adjusted for proper vector alignment, cast to Vector *
const Vector *vamplitudes = reinterpret_cast<const Vector *>(samplitudes);
// clear vector accumulator
float32x4_t accum = vdupq_n_f32(0);
// iterate over array getting sum of squares in vectorLength lanes.
size_t i;
for (i = 0; i < size - size % vectorLength /* compiler optimized */; i += vectorLength) {
const float32x4_t famplitude = convertToFloatVectorAmplitude(*vamplitudes++);
accum = vmlaq_f32(accum, famplitude, famplitude);
}
// narrow vectorLength lanes of floats
float32x2_t accum2 = vadd_f32(vget_low_f32(accum), vget_high_f32(accum)); // get stereo volume
accum2 = vpadd_f32(accum2, accum2); // combine to mono
// accumulate vector
accumulator += vget_lane_f32(accum2, 0);
// accumulate any trailing elements too small for vector size
for (; i < size; ++i) {
const float amp = (float)samplitudes[i];
accumulator += amp * amp;
}
return accumulator;
}
template <>
inline float energyMono<AUDIO_FORMAT_PCM_FLOAT>(const void *amplitudes, size_t size)
{
return energyMonoVector<float32x4_t, float>(amplitudes, size);
}
template <>
inline float energyMono<AUDIO_FORMAT_PCM_16_BIT>(const void *amplitudes, size_t size)
{
return energyMonoVector<int16x4_t, int16_t>(amplitudes, size)
* normalizeEnergy<AUDIO_FORMAT_PCM_16_BIT>();
}
// fast int32_t power computation for PCM_32
template <>
inline float energyMono<AUDIO_FORMAT_PCM_32_BIT>(const void *amplitudes, size_t size)
{
return energyMonoVector<int32x4_t, int32_t>(amplitudes, size)
* normalizeEnergy<AUDIO_FORMAT_PCM_32_BIT>();
}
// fast int32_t power computation for PCM_8_24 (essentially identical to PCM_32 above)
template <>
inline float energyMono<AUDIO_FORMAT_PCM_8_24_BIT>(const void *amplitudes, size_t size)
{
return energyMonoVector<int32x4_t, int32_t>(amplitudes, size)
* normalizeEnergy<AUDIO_FORMAT_PCM_8_24_BIT>();
}
#endif // USE_NEON
} // namespace
float audio_utils_compute_energy_mono(const void *buffer, audio_format_t format, size_t samples)
{
switch (format) {
case AUDIO_FORMAT_PCM_8_BIT:
return energyMono<AUDIO_FORMAT_PCM_8_BIT>(buffer, samples);
case AUDIO_FORMAT_PCM_16_BIT:
return energyMono<AUDIO_FORMAT_PCM_16_BIT>(buffer, samples);
case AUDIO_FORMAT_PCM_24_BIT_PACKED:
return energyMono<AUDIO_FORMAT_PCM_24_BIT_PACKED>(buffer, samples);
case AUDIO_FORMAT_PCM_8_24_BIT:
return energyMono<AUDIO_FORMAT_PCM_8_24_BIT>(buffer, samples);
case AUDIO_FORMAT_PCM_32_BIT:
return energyMono<AUDIO_FORMAT_PCM_32_BIT>(buffer, samples);
case AUDIO_FORMAT_PCM_FLOAT:
return energyMono<AUDIO_FORMAT_PCM_FLOAT>(buffer, samples);
default:
LOG_ALWAYS_FATAL("invalid format: %#x", format);
}
}
float audio_utils_compute_power_mono(const void *buffer, audio_format_t format, size_t samples)
{
return audio_utils_power_from_energy(
audio_utils_compute_energy_mono(buffer, format, samples) / samples);
}
bool audio_utils_is_compute_power_format_supported(audio_format_t format)
{
return isFormatSupported(format);
}