mirror of
https://github.com/Ryujinx/Ryujinx.git
synced 2024-09-12 02:38:50 +02:00
91 lines
2.5 KiB
C#
91 lines
2.5 KiB
C#
|
namespace Ryujinx.Audio.Adpcm
|
||
|
{
|
||
|
public static class AdpcmDecoder
|
||
|
{
|
||
|
private const int SamplesPerFrame = 14;
|
||
|
private const int BytesPerFrame = 8;
|
||
|
|
||
|
public static int[] Decode(byte[] Buffer, AdpcmDecoderContext Context)
|
||
|
{
|
||
|
int Samples = GetSamplesCountFromSize(Buffer.Length);
|
||
|
|
||
|
int[] Pcm = new int[Samples * 2];
|
||
|
|
||
|
short History0 = Context.History0;
|
||
|
short History1 = Context.History1;
|
||
|
|
||
|
int InputOffset = 0;
|
||
|
int OutputOffset = 0;
|
||
|
|
||
|
while (InputOffset < Buffer.Length)
|
||
|
{
|
||
|
byte Header = Buffer[InputOffset++];
|
||
|
|
||
|
int Scale = 0x800 << (Header & 0xf);
|
||
|
|
||
|
int CoeffIndex = (Header >> 4) & 7;
|
||
|
|
||
|
short Coeff0 = Context.Coefficients[CoeffIndex * 2 + 0];
|
||
|
short Coeff1 = Context.Coefficients[CoeffIndex * 2 + 1];
|
||
|
|
||
|
int FrameSamples = SamplesPerFrame;
|
||
|
|
||
|
if (FrameSamples > Samples)
|
||
|
{
|
||
|
FrameSamples = Samples;
|
||
|
}
|
||
|
|
||
|
int Value = 0;
|
||
|
|
||
|
for (int SampleIndex = 0; SampleIndex < FrameSamples; SampleIndex++)
|
||
|
{
|
||
|
int Sample;
|
||
|
|
||
|
if ((SampleIndex & 1) == 0)
|
||
|
{
|
||
|
Value = Buffer[InputOffset++];
|
||
|
|
||
|
Sample = (Value << 24) >> 28;
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
Sample = (Value << 28) >> 28;
|
||
|
}
|
||
|
|
||
|
int Prediction = Coeff0 * History0 + Coeff1 * History1;
|
||
|
|
||
|
Sample = (Sample * Scale + Prediction + 0x400) >> 11;
|
||
|
|
||
|
short SaturatedSample = DspUtils.Saturate(Sample);
|
||
|
|
||
|
History1 = History0;
|
||
|
History0 = SaturatedSample;
|
||
|
|
||
|
Pcm[OutputOffset++] = SaturatedSample;
|
||
|
Pcm[OutputOffset++] = SaturatedSample;
|
||
|
}
|
||
|
|
||
|
Samples -= FrameSamples;
|
||
|
}
|
||
|
|
||
|
Context.History0 = History0;
|
||
|
Context.History1 = History1;
|
||
|
|
||
|
return Pcm;
|
||
|
}
|
||
|
|
||
|
public static long GetSizeFromSamplesCount(int SamplesCount)
|
||
|
{
|
||
|
int Frames = SamplesCount / SamplesPerFrame;
|
||
|
|
||
|
return Frames * BytesPerFrame;
|
||
|
}
|
||
|
|
||
|
public static int GetSamplesCountFromSize(long Size)
|
||
|
{
|
||
|
int Frames = (int)(Size / BytesPerFrame);
|
||
|
|
||
|
return Frames * SamplesPerFrame;
|
||
|
}
|
||
|
}
|
||
|
}
|