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SPU: Fix off-by-one-sampling-error causing noise in output

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This commit is contained in:
Connor McLaughlin 2019-10-29 13:33:19 +10:00
parent 6f7b9c8e28
commit 40eb157d77
2 changed files with 13 additions and 14 deletions
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19
src/core/spu.cpp
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@ -677,19 +677,20 @@ void SPU::Voice::DecodeBlock(const ADPCMBlock& block)
for (u32 i = 0; i < NUM_SAMPLES_PER_ADPCM_BLOCK; i++) for (u32 i = 0; i < NUM_SAMPLES_PER_ADPCM_BLOCK; i++)
{ {
// extend 4-bit to 16-bit, apply shift from header and mix in previous samples // extend 4-bit to 16-bit, apply shift from header and mix in previous samples
const s16 sample = static_cast<s16>(ZeroExtend16(block.GetNibble(i)) << 12) >> shift; s32 sample = s32(static_cast<s16>(ZeroExtend16(block.GetNibble(i)) << 12) >> shift);
const s32 interp_sample = s32(sample) + ((last_samples[0] * filter_pos) + (last_samples[1] * filter_neg) + 32) / 64; sample += (last_samples[0] * filter_pos) >> 6;
sample += (last_samples[1] * filter_neg) >> 6;
current_block_samples[i] = Clamp16(interp_sample); current_block_samples[i] = Clamp16(sample);
last_samples[1] = last_samples[0]; last_samples[1] = last_samples[0];
last_samples[0] = interp_sample; last_samples[0] = sample;
} }
std::copy(last_samples, last_samples + countof(last_samples), adpcm_last_samples.begin()); std::copy(last_samples, last_samples + countof(last_samples), adpcm_last_samples.begin());
current_block_flags.bits = block.flags.bits; current_block_flags.bits = block.flags.bits;
} }
SPU::SampleFormat SPU::Voice::SampleBlock(s32 index) const s16 SPU::Voice::SampleBlock(s32 index) const
{ {
if (index < 0) if (index < 0)
{ {
@ -832,6 +833,10 @@ std::tuple<s32, s32> SPU::SampleVoice(u32 voice_index)
} }
} }
// interpolate/sample and apply ADSR volume
const s32 sample = ApplyVolume(voice.Interpolate(), voice.regs.adsr_volume);
voice.TickADSR();
// TODO: Pulse modulation // TODO: Pulse modulation
u16 step = voice.regs.adpcm_sample_rate; u16 step = voice.regs.adpcm_sample_rate;
step = std::min<u16>(step, 0x4000); step = std::min<u16>(step, 0x4000);
@ -864,10 +869,6 @@ std::tuple<s32, s32> SPU::SampleVoice(u32 voice_index)
} }
} }
// interpolate/sample and apply ADSR volume
const s32 sample = ApplyVolume(voice.Interpolate(), voice.regs.adsr_volume);
voice.TickADSR();
// apply per-channel volume // apply per-channel volume
const s32 left = ApplyVolume(sample, voice.regs.volume_left.GetVolume()); const s32 left = ApplyVolume(sample, voice.regs.volume_left.GetVolume());
const s32 right = ApplyVolume(sample, voice.regs.volume_right.GetVolume()); const s32 right = ApplyVolume(sample, voice.regs.volume_right.GetVolume());

8
src/core/spu.h
View file

@ -14,8 +14,6 @@ class InterruptController;
class SPU class SPU
{ {
public: public:
using SampleFormat = s16;
SPU(); SPU();
~SPU(); ~SPU();
@ -221,8 +219,8 @@ private:
VoiceRegisters regs; VoiceRegisters regs;
VoiceCounter counter; VoiceCounter counter;
ADPCMFlags current_block_flags; ADPCMFlags current_block_flags;
std::array<SampleFormat, NUM_SAMPLES_PER_ADPCM_BLOCK> current_block_samples; std::array<s16, NUM_SAMPLES_PER_ADPCM_BLOCK> current_block_samples;
std::array<SampleFormat, 3> previous_block_last_samples; std::array<s16, 3> previous_block_last_samples;
std::array<s32, 2> adpcm_last_samples; std::array<s32, 2> adpcm_last_samples;
ADSRPhase adsr_phase; ADSRPhase adsr_phase;
@ -238,7 +236,7 @@ private:
void KeyOff(); void KeyOff();
void DecodeBlock(const ADPCMBlock& block); void DecodeBlock(const ADPCMBlock& block);
SampleFormat SampleBlock(s32 index) const; s16 SampleBlock(s32 index) const;
s16 Interpolate() const; s16 Interpolate() const;
// Switches to the specified phase, filling in target. // Switches to the specified phase, filling in target.