215 lines
6.8 KiB
C++
215 lines
6.8 KiB
C++
/*
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* Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef COMMON_AUDIO_INCLUDE_AUDIO_UTIL_H_
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#define COMMON_AUDIO_INCLUDE_AUDIO_UTIL_H_
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#include <stdint.h>
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#include <algorithm>
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#include <cmath>
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#include <cstring>
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#include <limits>
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#include "rtc_base/checks.h"
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namespace webrtc {
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typedef std::numeric_limits<int16_t> limits_int16;
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// The conversion functions use the following naming convention:
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// S16: int16_t [-32768, 32767]
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// Float: float [-1.0, 1.0]
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// FloatS16: float [-32768.0, 32768.0]
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// Dbfs: float [-20.0*log(10, 32768), 0] = [-90.3, 0]
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// The ratio conversion functions use this naming convention:
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// Ratio: float (0, +inf)
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// Db: float (-inf, +inf)
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static inline float S16ToFloat(int16_t v) {
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constexpr float kScaling = 1.f / 32768.f;
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return v * kScaling;
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}
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static inline int16_t FloatS16ToS16(float v) {
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v = std::min(v, 32767.f);
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v = std::max(v, -32768.f);
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return static_cast<int16_t>(v + std::copysign(0.5f, v));
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}
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static inline int16_t FloatToS16(float v) {
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v *= 32768.f;
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v = std::min(v, 32767.f);
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v = std::max(v, -32768.f);
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return static_cast<int16_t>(v + std::copysign(0.5f, v));
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}
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static inline float FloatToFloatS16(float v) {
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v = std::min(v, 1.f);
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v = std::max(v, -1.f);
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return v * 32768.f;
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}
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static inline float FloatS16ToFloat(float v) {
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v = std::min(v, 32768.f);
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v = std::max(v, -32768.f);
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constexpr float kScaling = 1.f / 32768.f;
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return v * kScaling;
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}
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void FloatToS16(const float* src, size_t size, int16_t* dest);
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void S16ToFloat(const int16_t* src, size_t size, float* dest);
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void S16ToFloatS16(const int16_t* src, size_t size, float* dest);
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void FloatS16ToS16(const float* src, size_t size, int16_t* dest);
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void FloatToFloatS16(const float* src, size_t size, float* dest);
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void FloatS16ToFloat(const float* src, size_t size, float* dest);
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inline float DbToRatio(float v) {
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return std::pow(10.0f, v / 20.0f);
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}
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inline float DbfsToFloatS16(float v) {
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static constexpr float kMaximumAbsFloatS16 = -limits_int16::min();
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return DbToRatio(v) * kMaximumAbsFloatS16;
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}
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inline float FloatS16ToDbfs(float v) {
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RTC_DCHECK_GE(v, 0);
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// kMinDbfs is equal to -20.0 * log10(-limits_int16::min())
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static constexpr float kMinDbfs = -90.30899869919436f;
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if (v <= 1.0f) {
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return kMinDbfs;
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}
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// Equal to 20 * log10(v / (-limits_int16::min()))
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return 20.0f * std::log10(v) + kMinDbfs;
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}
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// Copy audio from |src| channels to |dest| channels unless |src| and |dest|
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// point to the same address. |src| and |dest| must have the same number of
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// channels, and there must be sufficient space allocated in |dest|.
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template <typename T>
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void CopyAudioIfNeeded(const T* const* src,
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int num_frames,
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int num_channels,
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T* const* dest) {
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for (int i = 0; i < num_channels; ++i) {
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if (src[i] != dest[i]) {
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std::copy(src[i], src[i] + num_frames, dest[i]);
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}
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}
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}
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// Deinterleave audio from |interleaved| to the channel buffers pointed to
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// by |deinterleaved|. There must be sufficient space allocated in the
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// |deinterleaved| buffers (|num_channel| buffers with |samples_per_channel|
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// per buffer).
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template <typename T>
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void Deinterleave(const T* interleaved,
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size_t samples_per_channel,
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size_t num_channels,
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T* const* deinterleaved) {
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for (size_t i = 0; i < num_channels; ++i) {
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T* channel = deinterleaved[i];
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size_t interleaved_idx = i;
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for (size_t j = 0; j < samples_per_channel; ++j) {
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channel[j] = interleaved[interleaved_idx];
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interleaved_idx += num_channels;
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}
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}
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}
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// Interleave audio from the channel buffers pointed to by |deinterleaved| to
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// |interleaved|. There must be sufficient space allocated in |interleaved|
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// (|samples_per_channel| * |num_channels|).
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template <typename T>
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void Interleave(const T* const* deinterleaved,
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size_t samples_per_channel,
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size_t num_channels,
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T* interleaved) {
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for (size_t i = 0; i < num_channels; ++i) {
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const T* channel = deinterleaved[i];
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size_t interleaved_idx = i;
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for (size_t j = 0; j < samples_per_channel; ++j) {
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interleaved[interleaved_idx] = channel[j];
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interleaved_idx += num_channels;
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}
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}
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}
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// Copies audio from a single channel buffer pointed to by |mono| to each
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// channel of |interleaved|. There must be sufficient space allocated in
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// |interleaved| (|samples_per_channel| * |num_channels|).
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template <typename T>
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void UpmixMonoToInterleaved(const T* mono,
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int num_frames,
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int num_channels,
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T* interleaved) {
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int interleaved_idx = 0;
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for (int i = 0; i < num_frames; ++i) {
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for (int j = 0; j < num_channels; ++j) {
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interleaved[interleaved_idx++] = mono[i];
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}
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}
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}
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template <typename T, typename Intermediate>
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void DownmixToMono(const T* const* input_channels,
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size_t num_frames,
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int num_channels,
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T* out) {
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for (size_t i = 0; i < num_frames; ++i) {
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Intermediate value = input_channels[0][i];
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for (int j = 1; j < num_channels; ++j) {
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value += input_channels[j][i];
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}
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out[i] = value / num_channels;
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}
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}
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// Downmixes an interleaved multichannel signal to a single channel by averaging
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// all channels.
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template <typename T, typename Intermediate>
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void DownmixInterleavedToMonoImpl(const T* interleaved,
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size_t num_frames,
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int num_channels,
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T* deinterleaved) {
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RTC_DCHECK_GT(num_channels, 0);
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RTC_DCHECK_GT(num_frames, 0);
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const T* const end = interleaved + num_frames * num_channels;
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while (interleaved < end) {
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const T* const frame_end = interleaved + num_channels;
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Intermediate value = *interleaved++;
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while (interleaved < frame_end) {
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value += *interleaved++;
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}
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*deinterleaved++ = value / num_channels;
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}
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}
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template <typename T>
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void DownmixInterleavedToMono(const T* interleaved,
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size_t num_frames,
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int num_channels,
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T* deinterleaved);
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template <>
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void DownmixInterleavedToMono<int16_t>(const int16_t* interleaved,
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size_t num_frames,
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int num_channels,
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int16_t* deinterleaved);
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} // namespace webrtc
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#endif // COMMON_AUDIO_INCLUDE_AUDIO_UTIL_H_
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