Merge pull request #1572 from MerryMage/audio-filter

DSP: Implement audio filters (simple, biquad)
This commit is contained in:
bunnei 2016-03-30 20:17:52 -04:00
commit 644fbbeb13
5 changed files with 275 additions and 7 deletions

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@ -2,13 +2,16 @@ set(SRCS
audio_core.cpp
codec.cpp
hle/dsp.cpp
hle/filter.cpp
hle/pipe.cpp
)
set(HEADERS
audio_core.h
codec.h
hle/common.h
hle/dsp.h
hle/filter.h
hle/pipe.h
sink.h
)

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@ -0,0 +1,35 @@
// Copyright 2016 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#pragma once
#include <algorithm>
#include <array>
#include "audio_core/audio_core.h"
#include "common/common_types.h"
namespace DSP {
namespace HLE {
/// The final output to the speakers is stereo. Preprocessing output in Source is also stereo.
using StereoFrame16 = std::array<std::array<s16, 2>, AudioCore::samples_per_frame>;
/// The DSP is quadraphonic internally.
using QuadFrame32 = std::array<std::array<s32, 4>, AudioCore::samples_per_frame>;
/**
* This performs the filter operation defined by FilterT::ProcessSample on the frame in-place.
* FilterT::ProcessSample is called sequentially on the samples.
*/
template<typename FrameT, typename FilterT>
void FilterFrame(FrameT& frame, FilterT& filter) {
std::transform(frame.begin(), frame.end(), frame.begin(), [&filter](const typename FrameT::value_type& sample) {
return filter.ProcessSample(sample);
});
}
} // namespace HLE
} // namespace DSP

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@ -126,8 +126,11 @@ struct SourceConfiguration {
union {
u32_le dirty_raw;
BitField<0, 1, u32_le> format_dirty;
BitField<1, 1, u32_le> mono_or_stereo_dirty;
BitField<2, 1, u32_le> adpcm_coefficients_dirty;
BitField<3, 1, u32_le> partial_embedded_buffer_dirty; ///< Tends to be set when a looped buffer is queued.
BitField<4, 1, u32_le> partial_reset_flag;
BitField<16, 1, u32_le> enable_dirty;
BitField<17, 1, u32_le> interpolation_dirty;
@ -143,8 +146,7 @@ struct SourceConfiguration {
BitField<27, 1, u32_le> gain_2_dirty;
BitField<28, 1, u32_le> sync_dirty;
BitField<29, 1, u32_le> reset_flag;
BitField<31, 1, u32_le> embedded_buffer_dirty;
BitField<30, 1, u32_le> embedded_buffer_dirty;
};
// Gain control
@ -175,7 +177,8 @@ struct SourceConfiguration {
/**
* This is the simplest normalized first-order digital recursive filter.
* The transfer function of this filter is:
* H(z) = b0 / (1 + a1 z^-1)
* H(z) = b0 / (1 - a1 z^-1)
* Note the feedbackward coefficient is negated.
* Values are signed fixed point with 15 fractional bits.
*/
struct SimpleFilter {
@ -192,11 +195,11 @@ struct SourceConfiguration {
* Values are signed fixed point with 14 fractional bits.
*/
struct BiquadFilter {
s16_le b0;
s16_le b1;
s16_le b2;
s16_le a1;
s16_le a2;
s16_le a1;
s16_le b2;
s16_le b1;
s16_le b0;
};
union {

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@ -0,0 +1,115 @@
// Copyright 2016 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <array>
#include <cstddef>
#include "audio_core/hle/common.h"
#include "audio_core/hle/dsp.h"
#include "audio_core/hle/filter.h"
#include "common/common_types.h"
#include "common/math_util.h"
namespace DSP {
namespace HLE {
void SourceFilters::Reset() {
Enable(false, false);
}
void SourceFilters::Enable(bool simple, bool biquad) {
simple_filter_enabled = simple;
biquad_filter_enabled = biquad;
if (!simple)
simple_filter.Reset();
if (!biquad)
biquad_filter.Reset();
}
void SourceFilters::Configure(SourceConfiguration::Configuration::SimpleFilter config) {
simple_filter.Configure(config);
}
void SourceFilters::Configure(SourceConfiguration::Configuration::BiquadFilter config) {
biquad_filter.Configure(config);
}
void SourceFilters::ProcessFrame(StereoFrame16& frame) {
if (!simple_filter_enabled && !biquad_filter_enabled)
return;
if (simple_filter_enabled) {
FilterFrame(frame, simple_filter);
}
if (biquad_filter_enabled) {
FilterFrame(frame, biquad_filter);
}
}
// SimpleFilter
void SourceFilters::SimpleFilter::Reset() {
y1.fill(0);
// Configure as passthrough.
a1 = 0;
b0 = 1 << 15;
}
void SourceFilters::SimpleFilter::Configure(SourceConfiguration::Configuration::SimpleFilter config) {
a1 = config.a1;
b0 = config.b0;
}
std::array<s16, 2> SourceFilters::SimpleFilter::ProcessSample(const std::array<s16, 2>& x0) {
std::array<s16, 2> y0;
for (size_t i = 0; i < 2; i++) {
const s32 tmp = (b0 * x0[i] + a1 * y1[i]) >> 15;
y0[i] = MathUtil::Clamp(tmp, -32768, 32767);
}
y1 = y0;
return y0;
}
// BiquadFilter
void SourceFilters::BiquadFilter::Reset() {
x1.fill(0);
x2.fill(0);
y1.fill(0);
y2.fill(0);
// Configure as passthrough.
a1 = a2 = b1 = b2 = 0;
b0 = 1 << 14;
}
void SourceFilters::BiquadFilter::Configure(SourceConfiguration::Configuration::BiquadFilter config) {
a1 = config.a1;
a2 = config.a2;
b0 = config.b0;
b1 = config.b1;
b2 = config.b2;
}
std::array<s16, 2> SourceFilters::BiquadFilter::ProcessSample(const std::array<s16, 2>& x0) {
std::array<s16, 2> y0;
for (size_t i = 0; i < 2; i++) {
const s32 tmp = (b0 * x0[i] + b1 * x1[i] + b2 * x2[i] + a1 * y1[i] + a2 * y2[i]) >> 14;
y0[i] = MathUtil::Clamp(tmp, -32768, 32767);
}
x2 = x1;
x1 = x0;
y2 = y1;
y1 = y0;
return y0;
}
} // namespace HLE
} // namespace DSP

112
src/audio_core/hle/filter.h Normal file
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@ -0,0 +1,112 @@
// Copyright 2016 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#pragma once
#include <array>
#include "audio_core/hle/common.h"
#include "audio_core/hle/dsp.h"
#include "common/common_types.h"
namespace DSP {
namespace HLE {
/// Preprocessing filters. There is an independent set of filters for each Source.
class SourceFilters final {
SourceFilters() { Reset(); }
/// Reset internal state.
void Reset();
/**
* Enable/Disable filters
* See also: SourceConfiguration::Configuration::simple_filter_enabled,
* SourceConfiguration::Configuration::biquad_filter_enabled.
* @param simple If true, enables the simple filter. If false, disables it.
* @param simple If true, enables the biquad filter. If false, disables it.
*/
void Enable(bool simple, bool biquad);
/**
* Configure simple filter.
* @param config Configuration from DSP shared memory.
*/
void Configure(SourceConfiguration::Configuration::SimpleFilter config);
/**
* Configure biquad filter.
* @param config Configuration from DSP shared memory.
*/
void Configure(SourceConfiguration::Configuration::BiquadFilter config);
/**
* Processes a frame in-place.
* @param frame Audio samples to process. Modified in-place.
*/
void ProcessFrame(StereoFrame16& frame);
private:
bool simple_filter_enabled;
bool biquad_filter_enabled;
struct SimpleFilter {
SimpleFilter() { Reset(); }
/// Resets internal state.
void Reset();
/**
* Configures this filter with application settings.
* @param config Configuration from DSP shared memory.
*/
void Configure(SourceConfiguration::Configuration::SimpleFilter config);
/**
* Processes a single stereo PCM16 sample.
* @param x0 Input sample
* @return Output sample
*/
std::array<s16, 2> ProcessSample(const std::array<s16, 2>& x0);
private:
// Configuration
s32 a1, b0;
// Internal state
std::array<s16, 2> y1;
} simple_filter;
struct BiquadFilter {
BiquadFilter() { Reset(); }
/// Resets internal state.
void Reset();
/**
* Configures this filter with application settings.
* @param config Configuration from DSP shared memory.
*/
void Configure(SourceConfiguration::Configuration::BiquadFilter config);
/**
* Processes a single stereo PCM16 sample.
* @param x0 Input sample
* @return Output sample
*/
std::array<s16, 2> ProcessSample(const std::array<s16, 2>& x0);
private:
// Configuration
s32 a1, a2, b0, b1, b2;
// Internal state
std::array<s16, 2> x1;
std::array<s16, 2> x2;
std::array<s16, 2> y1;
std::array<s16, 2> y2;
} biquad_filter;
};
} // namespace HLE
} // namespace DSP