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-rw-r--r--src/audio_core/interpolate.cpp31
1 files changed, 16 insertions, 15 deletions
diff --git a/src/audio_core/interpolate.cpp b/src/audio_core/interpolate.cpp
index fcd3aa066..8a5d4181a 100644
--- a/src/audio_core/interpolate.cpp
+++ b/src/audio_core/interpolate.cpp
@@ -3,7 +3,6 @@
3// Refer to the license.txt file included. 3// Refer to the license.txt file included.
4 4
5#include "audio_core/interpolate.h" 5#include "audio_core/interpolate.h"
6
7#include "common/assert.h" 6#include "common/assert.h"
8#include "common/math_util.h" 7#include "common/math_util.h"
9 8
@@ -17,7 +16,8 @@ constexpr u64 scale_mask = scale_factor - 1;
17/// Here we step over the input in steps of rate_multiplier, until we consume all of the input. 16/// Here we step over the input in steps of rate_multiplier, until we consume all of the input.
18/// Three adjacent samples are passed to fn each step. 17/// Three adjacent samples are passed to fn each step.
19template <typename Function> 18template <typename Function>
20static StereoBuffer16 StepOverSamples(State& state, const StereoBuffer16& input, float rate_multiplier, Function fn) { 19static StereoBuffer16 StepOverSamples(State& state, const StereoBuffer16& input,
20 float rate_multiplier, Function fn) {
21 ASSERT(rate_multiplier > 0); 21 ASSERT(rate_multiplier > 0);
22 22
23 if (input.size() < 2) 23 if (input.size() < 2)
@@ -63,23 +63,24 @@ static StereoBuffer16 StepOverSamples(State& state, const StereoBuffer16& input,
63} 63}
64 64
65StereoBuffer16 None(State& state, const StereoBuffer16& input, float rate_multiplier) { 65StereoBuffer16 None(State& state, const StereoBuffer16& input, float rate_multiplier) {
66 return StepOverSamples(state, input, rate_multiplier, [](u64 fraction, const auto& x0, const auto& x1, const auto& x2) { 66 return StepOverSamples(
67 return x0; 67 state, input, rate_multiplier,
68 }); 68 [](u64 fraction, const auto& x0, const auto& x1, const auto& x2) { return x0; });
69} 69}
70 70
71StereoBuffer16 Linear(State& state, const StereoBuffer16& input, float rate_multiplier) { 71StereoBuffer16 Linear(State& state, const StereoBuffer16& input, float rate_multiplier) {
72 // Note on accuracy: Some values that this produces are +/- 1 from the actual firmware. 72 // Note on accuracy: Some values that this produces are +/- 1 from the actual firmware.
73 return StepOverSamples(state, input, rate_multiplier, [](u64 fraction, const auto& x0, const auto& x1, const auto& x2) { 73 return StepOverSamples(state, input, rate_multiplier,
74 // This is a saturated subtraction. (Verified by black-box fuzzing.) 74 [](u64 fraction, const auto& x0, const auto& x1, const auto& x2) {
75 s64 delta0 = MathUtil::Clamp<s64>(x1[0] - x0[0], -32768, 32767); 75 // This is a saturated subtraction. (Verified by black-box fuzzing.)
76 s64 delta1 = MathUtil::Clamp<s64>(x1[1] - x0[1], -32768, 32767); 76 s64 delta0 = MathUtil::Clamp<s64>(x1[0] - x0[0], -32768, 32767);
77 77 s64 delta1 = MathUtil::Clamp<s64>(x1[1] - x0[1], -32768, 32767);
78 return std::array<s16, 2> { 78
79 static_cast<s16>(x0[0] + fraction * delta0 / scale_factor), 79 return std::array<s16, 2>{
80 static_cast<s16>(x0[1] + fraction * delta1 / scale_factor) 80 static_cast<s16>(x0[0] + fraction * delta0 / scale_factor),
81 }; 81 static_cast<s16>(x0[1] + fraction * delta1 / scale_factor),
82 }); 82 };
83 });
83} 84}
84 85
85} // namespace AudioInterp 86} // namespace AudioInterp