mirror of
https://github.com/Ryujinx/Ryujinx.git
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7b66cb0d90
* audio: Cleanup SoundIO and fix OpenAL issue * fix tabs by spaces * Fix extra spaces * Fix SoundIO.cs * Fix ContainsAudioOutBuffer
125 lines
4.7 KiB
C#
125 lines
4.7 KiB
C#
using System;
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using System.Runtime.CompilerServices;
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using System.Runtime.InteropServices;
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namespace Ryujinx.Audio
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{
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public static class Downmixing
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{
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[StructLayout(LayoutKind.Sequential, Pack = 1)]
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private struct Channel51FormatPCM16
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{
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public short FrontLeft;
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public short FrontRight;
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public short FrontCenter;
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public short LowFrequency;
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public short BackLeft;
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public short BackRight;
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}
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[StructLayout(LayoutKind.Sequential, Pack = 1)]
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private struct ChannelStereoFormatPCM16
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{
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public short Left;
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public short Right;
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}
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private const int Q15Bits = 16;
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private const int RawQ15One = 1 << Q15Bits;
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private const int RawQ15HalfOne = (int)(0.5f * RawQ15One);
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private const int Minus3dBInQ15 = (int)(0.707f * RawQ15One);
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private const int Minus6dBInQ15 = (int)(0.501f * RawQ15One);
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private const int Minus12dBInQ15 = (int)(0.251f * RawQ15One);
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private static readonly int[] DefaultSurroundToStereoCoefficients = new int[4]
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{
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RawQ15One,
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Minus3dBInQ15,
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Minus12dBInQ15,
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Minus3dBInQ15
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};
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private static readonly int[] DefaultStereoToMonoCoefficients = new int[2]
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{
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Minus6dBInQ15,
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Minus6dBInQ15
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};
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private const int SurroundChannelCount = 6;
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private const int StereoChannelCount = 2;
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private const int MonoChannelCount = 1;
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private static ReadOnlySpan<Channel51FormatPCM16> GetSurroundBuffer(ReadOnlySpan<short> data)
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{
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return MemoryMarshal.Cast<short, Channel51FormatPCM16>(data);
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private static ReadOnlySpan<ChannelStereoFormatPCM16> GetStereoBuffer(ReadOnlySpan<short> data)
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{
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return MemoryMarshal.Cast<short, ChannelStereoFormatPCM16>(data);
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private static short DownMixStereoToMono(ReadOnlySpan<int> coefficients, short left, short right)
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{
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return (short)((left * coefficients[0] + right * coefficients[1]) >> Q15Bits);
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private static short DownMixSurroundToStereo(ReadOnlySpan<int> coefficients, short back, short lfe, short center, short front)
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{
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return (short)((coefficients[3] * back + coefficients[2] * lfe + coefficients[1] * center + coefficients[0] * front + RawQ15HalfOne) >> Q15Bits);
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private static short[] DownMixSurroundToStereo(ReadOnlySpan<int> coefficients, ReadOnlySpan<short> data)
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{
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int samplePerChannelCount = data.Length / SurroundChannelCount;
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short[] downmixedBuffer = new short[samplePerChannelCount * StereoChannelCount];
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ReadOnlySpan<Channel51FormatPCM16> channels = GetSurroundBuffer(data);
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for (int i = 0; i < samplePerChannelCount; i++)
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{
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Channel51FormatPCM16 channel = channels[i];
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downmixedBuffer[i * 2] = DownMixSurroundToStereo(coefficients, channel.BackLeft, channel.LowFrequency, channel.FrontCenter, channel.FrontLeft);
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downmixedBuffer[i * 2 + 1] = DownMixSurroundToStereo(coefficients, channel.BackRight, channel.LowFrequency, channel.FrontCenter, channel.FrontRight);
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}
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return downmixedBuffer;
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private static short[] DownMixStereoToMono(ReadOnlySpan<int> coefficients, ReadOnlySpan<short> data)
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{
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int samplePerChannelCount = data.Length / StereoChannelCount;
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short[] downmixedBuffer = new short[samplePerChannelCount * MonoChannelCount];
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ReadOnlySpan<ChannelStereoFormatPCM16> channels = GetStereoBuffer(data);
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for (int i = 0; i < samplePerChannelCount; i++)
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{
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ChannelStereoFormatPCM16 channel = channels[i];
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downmixedBuffer[i] = DownMixStereoToMono(coefficients, channel.Left, channel.Right);
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}
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return downmixedBuffer;
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}
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public static short[] DownMixStereoToMono(ReadOnlySpan<short> data)
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{
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return DownMixStereoToMono(DefaultStereoToMonoCoefficients, data);
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}
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public static short[] DownMixSurroundToStereo(ReadOnlySpan<short> data)
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{
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return DownMixSurroundToStereo(DefaultSurroundToStereoCoefficients, data);
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}
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}
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}
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