From 41bba5310a5324f54fa5c0200aff2bf697ced000 Mon Sep 17 00:00:00 2001
From: merry <git@mary.rs>
Date: Sun, 15 Jan 2023 04:20:49 +0000
Subject: [PATCH] Audren: Implement polyphase upsampler (#4256)
* Audren: Implement polyphase upsampler
* prefer shifting to modulo
* prefer MathF
* fix nits
* rm ResampleForUpsampler
* oop
* Array20
* nits
---
.../Renderer/Dsp/Command/UpsampleCommand.cs | 12 +-
Ryujinx.Audio/Renderer/Dsp/ResamplerHelper.cs | 47 -----
Ryujinx.Audio/Renderer/Dsp/UpsamplerHelper.cs | 175 ++++++++++++++++++
.../Server/Upsampler/UpsamplerBufferState.cs | 14 ++
.../Server/Upsampler/UpsamplerState.cs | 5 +
5 files changed, 201 insertions(+), 52 deletions(-)
create mode 100644 Ryujinx.Audio/Renderer/Dsp/UpsamplerHelper.cs
create mode 100644 Ryujinx.Audio/Renderer/Server/Upsampler/UpsamplerBufferState.cs
diff --git a/Ryujinx.Audio/Renderer/Dsp/Command/UpsampleCommand.cs b/Ryujinx.Audio/Renderer/Dsp/Command/UpsampleCommand.cs
index 1617a6421d..0870d59ce7 100644
--- a/Ryujinx.Audio/Renderer/Dsp/Command/UpsampleCommand.cs
+++ b/Ryujinx.Audio/Renderer/Dsp/Command/UpsampleCommand.cs
@@ -40,6 +40,12 @@ namespace Ryujinx.Audio.Renderer.Dsp.Command
info.InputBufferIndices[i] = (ushort)(bufferOffset + inputBufferOffset[i]);
}
+ if (info.BufferStates?.Length != (int)inputCount)
+ {
+ // Keep state if possible.
+ info.BufferStates = new UpsamplerBufferState[(int)inputCount];
+ }
+
UpsamplerInfo = info;
}
@@ -50,8 +56,6 @@ namespace Ryujinx.Audio.Renderer.Dsp.Command
public void Process(CommandList context)
{
- float ratio = (float)InputSampleRate / Constants.TargetSampleRate;
-
uint bufferCount = Math.Min(BufferCount, UpsamplerInfo.SourceSampleCount);
for (int i = 0; i < bufferCount; i++)
@@ -59,9 +63,7 @@ namespace Ryujinx.Audio.Renderer.Dsp.Command
Span<float> inputBuffer = context.GetBuffer(UpsamplerInfo.InputBufferIndices[i]);
Span<float> outputBuffer = GetBuffer(UpsamplerInfo.InputBufferIndices[i], (int)UpsamplerInfo.SampleCount);
- float fraction = 0.0f;
-
- ResamplerHelper.ResampleForUpsampler(outputBuffer, inputBuffer, ratio, ref fraction, (int)(InputSampleCount / ratio));
+ UpsamplerHelper.Upsample(outputBuffer, inputBuffer, (int)UpsamplerInfo.SampleCount, (int)InputSampleCount, ref UpsamplerInfo.BufferStates[i]);
}
}
}
diff --git a/Ryujinx.Audio/Renderer/Dsp/ResamplerHelper.cs b/Ryujinx.Audio/Renderer/Dsp/ResamplerHelper.cs
index 4de2e078a9..b46a33fe06 100644
--- a/Ryujinx.Audio/Renderer/Dsp/ResamplerHelper.cs
+++ b/Ryujinx.Audio/Renderer/Dsp/ResamplerHelper.cs
@@ -579,52 +579,5 @@ namespace Ryujinx.Audio.Renderer.Dsp
fraction -= (int)fraction;
}
}
-
- [MethodImpl(MethodImplOptions.AggressiveInlining)]
- public static void ResampleForUpsampler(Span<float> outputBuffer, ReadOnlySpan<float> inputBuffer, float ratio, ref float fraction, int sampleCount)
- {
- // Currently a simple cubic interpolation, assuming duplicated values at edges.
- // TODO: Discover and use algorithm that the switch uses.
-
- int inputBufferIndex = 0;
- int maxIndex = inputBuffer.Length - 1;
- int cubicEnd = inputBuffer.Length - 3;
-
- for (int i = 0; i < sampleCount; i++)
- {
- float s0, s1, s2, s3;
-
- s1 = inputBuffer[inputBufferIndex];
-
- if (inputBufferIndex == 0 || inputBufferIndex > cubicEnd)
- {
- // Clamp interplation values at the ends of the input buffer.
- s0 = inputBuffer[Math.Max(0, inputBufferIndex - 1)];
- s2 = inputBuffer[Math.Min(maxIndex, inputBufferIndex + 1)];
- s3 = inputBuffer[Math.Min(maxIndex, inputBufferIndex + 2)];
- }
- else
- {
- s0 = inputBuffer[inputBufferIndex - 1];
- s2 = inputBuffer[inputBufferIndex + 1];
- s3 = inputBuffer[inputBufferIndex + 2];
- }
-
- float a = s3 - s2 - s0 + s1;
- float b = s0 - s1 - a;
- float c = s2 - s0;
- float d = s1;
-
- float f2 = fraction * fraction;
- float f3 = f2 * fraction;
-
- outputBuffer[i] = a * f3 + b * f2 + c * fraction + d;
-
- fraction += ratio;
- inputBufferIndex += (int)MathF.Truncate(fraction);
-
- fraction -= (int)fraction;
- }
- }
}
}
\ No newline at end of file
diff --git a/Ryujinx.Audio/Renderer/Dsp/UpsamplerHelper.cs b/Ryujinx.Audio/Renderer/Dsp/UpsamplerHelper.cs
new file mode 100644
index 0000000000..847acec2e9
--- /dev/null
+++ b/Ryujinx.Audio/Renderer/Dsp/UpsamplerHelper.cs
@@ -0,0 +1,175 @@
+using Ryujinx.Audio.Renderer.Server.Upsampler;
+using Ryujinx.Common.Memory;
+using System;
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+
+namespace Ryujinx.Audio.Renderer.Dsp
+{
+ public class UpsamplerHelper
+ {
+ private const int HistoryLength = UpsamplerBufferState.HistoryLength;
+ private const int FilterBankLength = 20;
+ // Bank0 = [0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
+ private const int Bank0CenterIndex = 9;
+ private static readonly Array20<float> Bank1 = PrecomputeFilterBank(1.0f / 6.0f);
+ private static readonly Array20<float> Bank2 = PrecomputeFilterBank(2.0f / 6.0f);
+ private static readonly Array20<float> Bank3 = PrecomputeFilterBank(3.0f / 6.0f);
+ private static readonly Array20<float> Bank4 = PrecomputeFilterBank(4.0f / 6.0f);
+ private static readonly Array20<float> Bank5 = PrecomputeFilterBank(5.0f / 6.0f);
+
+ private static Array20<float> PrecomputeFilterBank(float offset)
+ {
+ float Sinc(float x)
+ {
+ if (x == 0)
+ {
+ return 1.0f;
+ }
+ return (MathF.Sin(MathF.PI * x) / (MathF.PI * x));
+ }
+
+ float BlackmanWindow(float x)
+ {
+ const float a = 0.18f;
+ const float a0 = 0.5f - 0.5f * a;
+ const float a1 = -0.5f;
+ const float a2 = 0.5f * a;
+ return a0 + a1 * MathF.Cos(2 * MathF.PI * x) + a2 * MathF.Cos(4 * MathF.PI * x);
+ }
+
+ Array20<float> result = new Array20<float>();
+
+ for (int i = 0; i < FilterBankLength; i++)
+ {
+ float x = (Bank0CenterIndex - i) + offset;
+ result[i] = Sinc(x) * BlackmanWindow(x / FilterBankLength + 0.5f);
+ }
+
+ return result;
+ }
+
+ // Polyphase upsampling algorithm
+ [MethodImpl(MethodImplOptions.AggressiveInlining)]
+ public static void Upsample(Span<float> outputBuffer, ReadOnlySpan<float> inputBuffer, int outputSampleCount, int inputSampleCount, ref UpsamplerBufferState state)
+ {
+ if (!state.Initialized)
+ {
+ state.Scale = inputSampleCount switch
+ {
+ 40 => 6.0f,
+ 80 => 3.0f,
+ 160 => 1.5f,
+ _ => throw new ArgumentOutOfRangeException()
+ };
+ state.Initialized = true;
+ }
+
+ if (outputSampleCount == 0)
+ {
+ return;
+ }
+
+ [MethodImpl(MethodImplOptions.AggressiveInlining)]
+ float DoFilterBank(ref UpsamplerBufferState state, in Array20<float> bank)
+ {
+ float result = 0.0f;
+
+ Debug.Assert(state.History.Length == HistoryLength);
+ Debug.Assert(bank.Length == FilterBankLength);
+ for (int j = 0; j < FilterBankLength; j++)
+ {
+ result += bank[j] * state.History[j];
+ }
+
+ return result;
+ }
+
+ [MethodImpl(MethodImplOptions.AggressiveInlining)]
+ void NextInput(ref UpsamplerBufferState state, float input)
+ {
+ state.History.AsSpan().Slice(1).CopyTo(state.History.AsSpan());
+ state.History[HistoryLength - 1] = input;
+ }
+
+ int inputBufferIndex = 0;
+
+ switch (state.Scale)
+ {
+ case 6.0f:
+ for (int i = 0; i < outputSampleCount; i++)
+ {
+ switch (state.Phase)
+ {
+ case 0:
+ NextInput(ref state, inputBuffer[inputBufferIndex++]);
+ outputBuffer[i] = state.History[Bank0CenterIndex];
+ break;
+ case 1:
+ outputBuffer[i] = DoFilterBank(ref state, Bank1);
+ break;
+ case 2:
+ outputBuffer[i] = DoFilterBank(ref state, Bank2);
+ break;
+ case 3:
+ outputBuffer[i] = DoFilterBank(ref state, Bank3);
+ break;
+ case 4:
+ outputBuffer[i] = DoFilterBank(ref state, Bank4);
+ break;
+ case 5:
+ outputBuffer[i] = DoFilterBank(ref state, Bank5);
+ break;
+ }
+
+ state.Phase = (state.Phase + 1) % 6;
+ }
+ break;
+ case 3.0f:
+ for (int i = 0; i < outputSampleCount; i++)
+ {
+ switch (state.Phase)
+ {
+ case 0:
+ NextInput(ref state, inputBuffer[inputBufferIndex++]);
+ outputBuffer[i] = state.History[Bank0CenterIndex];
+ break;
+ case 1:
+ outputBuffer[i] = DoFilterBank(ref state, Bank2);
+ break;
+ case 2:
+ outputBuffer[i] = DoFilterBank(ref state, Bank4);
+ break;
+ }
+
+ state.Phase = (state.Phase + 1) % 3;
+ }
+ break;
+ case 1.5f:
+ // Upsample by 3 then decimate by 2.
+ for (int i = 0; i < outputSampleCount; i++)
+ {
+ switch (state.Phase)
+ {
+ case 0:
+ NextInput(ref state, inputBuffer[inputBufferIndex++]);
+ outputBuffer[i] = state.History[Bank0CenterIndex];
+ break;
+ case 1:
+ outputBuffer[i] = DoFilterBank(ref state, Bank4);
+ break;
+ case 2:
+ NextInput(ref state, inputBuffer[inputBufferIndex++]);
+ outputBuffer[i] = DoFilterBank(ref state, Bank2);
+ break;
+ }
+
+ state.Phase = (state.Phase + 1) % 3;
+ }
+ break;
+ default:
+ throw new ArgumentOutOfRangeException();
+ }
+ }
+ }
+}
\ No newline at end of file
diff --git a/Ryujinx.Audio/Renderer/Server/Upsampler/UpsamplerBufferState.cs b/Ryujinx.Audio/Renderer/Server/Upsampler/UpsamplerBufferState.cs
new file mode 100644
index 0000000000..a45fa8e5be
--- /dev/null
+++ b/Ryujinx.Audio/Renderer/Server/Upsampler/UpsamplerBufferState.cs
@@ -0,0 +1,14 @@
+using Ryujinx.Common.Memory;
+
+namespace Ryujinx.Audio.Renderer.Server.Upsampler
+{
+ public struct UpsamplerBufferState
+ {
+ public const int HistoryLength = 20;
+
+ public float Scale;
+ public Array20<float> History;
+ public bool Initialized;
+ public int Phase;
+ }
+}
\ No newline at end of file
diff --git a/Ryujinx.Audio/Renderer/Server/Upsampler/UpsamplerState.cs b/Ryujinx.Audio/Renderer/Server/Upsampler/UpsamplerState.cs
index 065e4838c7..e508f35b46 100644
--- a/Ryujinx.Audio/Renderer/Server/Upsampler/UpsamplerState.cs
+++ b/Ryujinx.Audio/Renderer/Server/Upsampler/UpsamplerState.cs
@@ -37,6 +37,11 @@ namespace Ryujinx.Audio.Renderer.Server.Upsampler
/// </summary>
public ushort[] InputBufferIndices;
+ /// <summary>
+ /// State of each input buffer index kept across invocations of the upsampler.
+ /// </summary>
+ public UpsamplerBufferState[] BufferStates;
+
/// <summary>
/// Create a new <see cref="UpsamplerState"/>.
/// </summary>