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Add HCA 3.0 decoding support #138

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1b5011b
include Version in HcaInfo
segfault-bilibili Feb 12, 2023
1631ff9
add hca3.0 decoding support
segfault-bilibili Feb 12, 2023
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127 changes: 113 additions & 14 deletions src/VGAudio/Codecs/CriHca/CriHcaPacking.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -57,17 +57,25 @@ public static void PackFrame(CriHcaFrame frame, Crc16 crc, byte[] outBuffer)
WriteChecksum(writer, crc, outBuffer);
}

public static int CalculateResolution(int scaleFactor, int noiseLevel)
private static int CalculateResolution(int scaleFactor, int noiseLevel, int version)
{
if (scaleFactor == 0)
{
return 0;
}
int curvePosition = noiseLevel - 5 * scaleFactor / 2 + 2;
//https://github.com/vgmstream/vgmstream/blob/4eecdada9a03a73af0c7c17f5cd6e08518fd7e3f/src/coding/hca_decoder_clhca.c#L1450
if (version >= 0x0300 && curvePosition >= 67) return 0; //FIXME
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@segfault-bilibili segfault-bilibili Feb 12, 2023

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It seems that version >= 0x3000 cannot be removed, otherwise HCA 2.0 decoding would break.

curvePosition = Helpers.Clamp(curvePosition, 0, 58);
return CriHcaTables.ScaleToResolutionCurve[curvePosition];
}

public static int CalculateResolution(int scaleFactor, int noiseLevel)
{
const int HcaVersion = 0x0200;
return CalculateResolution(scaleFactor, noiseLevel, HcaVersion);
}

private static bool UnpackFrameHeader(CriHcaFrame frame, BitReader reader)
{
int syncWord = reader.ReadInt(16);
Expand All @@ -82,31 +90,36 @@ private static bool UnpackFrameHeader(CriHcaFrame frame, BitReader reader)

foreach (CriHcaChannel channel in frame.Channels)
{
if (!ReadScaleFactors(channel, reader)) return false;
if (!ReadScaleFactors(channel, reader, frame.Hca.HfrGroupCount, frame.Hca.Version)) return false;

for (int i = 0; i < frame.EvaluationBoundary; i++)
for (int i = 0, newResolution = 0; i < frame.EvaluationBoundary; i++)
{
channel.Resolution[i] = CalculateResolution(channel.ScaleFactors[i], athCurve[i] + frame.AcceptableNoiseLevel - 1);
newResolution = CalculateResolution(channel.ScaleFactors[i], athCurve[i] + frame.AcceptableNoiseLevel - 1, frame.Hca.Version);
if (frame.Hca.Version >= 0x0300) newResolution = Helpers.Clamp(newResolution, frame.Hca.MinResolution, frame.Hca.MaxResolution);
channel.Resolution[i] = newResolution;
}

for (int i = frame.EvaluationBoundary; i < channel.CodedScaleFactorCount; i++)
for (int i = frame.EvaluationBoundary, newResolution = 0; i < channel.CodedScaleFactorCount; i++)
{
channel.Resolution[i] = CalculateResolution(channel.ScaleFactors[i], athCurve[i] + frame.AcceptableNoiseLevel);
newResolution = CalculateResolution(channel.ScaleFactors[i], athCurve[i] + frame.AcceptableNoiseLevel, frame.Hca.Version);
if (frame.Hca.Version >= 0x0300) newResolution = Helpers.Clamp(newResolution, frame.Hca.MinResolution, frame.Hca.MaxResolution);
channel.Resolution[i] = newResolution;
}

if (channel.Type == ChannelType.StereoSecondary)
{
ReadIntensity(reader, channel.Intensity);
ReadIntensity(reader, channel.Intensity, frame.Hca.Version);
}
else if (frame.Hca.HfrGroupCount > 0)
{
ReadHfrScaleFactors(reader, frame.Hca.HfrGroupCount, channel.HfrScales);
if (frame.Hca.Version < 0x0300) ReadHfrScaleFactors(reader, frame.Hca.HfrGroupCount, channel.HfrScales);
// v3.0 uses values derived in ReadScaleFactors
}
}
return true;
}

private static bool ReadScaleFactors(CriHcaChannel channel, BitReader reader)
private static bool ReadScaleFactors(CriHcaChannel channel, BitReader reader, int hfrGroupCount, int version)
{
channel.ScaleFactorDeltaBits = reader.ReadInt(3);
if (channel.ScaleFactorDeltaBits == 0)
Expand All @@ -115,23 +128,105 @@ private static bool ReadScaleFactors(CriHcaChannel channel, BitReader reader)
return true;
}

// added in v3.0
// https://github.com/vgmstream/vgmstream/blob/4eecdada9a03a73af0c7c17f5cd6e08518fd7e3f/src/coding/hca_decoder_clhca.c#L1287
int extraCodedScaleFactorCount;
int codedScaleFactorCount;
if (channel.Type == ChannelType.StereoSecondary || hfrGroupCount <= 0 || version < 0x0300)
{
extraCodedScaleFactorCount = 0;
codedScaleFactorCount = channel.CodedScaleFactorCount;
}
else
{
extraCodedScaleFactorCount = hfrGroupCount;
codedScaleFactorCount = channel.CodedScaleFactorCount + extraCodedScaleFactorCount;

// just in case
if (codedScaleFactorCount > SamplesPerSubFrame)
throw new InvalidDataException("codedScaleFactorCount > SamplesPerSubFrame");
}

if (channel.ScaleFactorDeltaBits >= 6)
{
for (int i = 0; i < channel.CodedScaleFactorCount; i++)
for (int i = 0; i < codedScaleFactorCount; i++)
{
channel.ScaleFactors[i] = reader.ReadInt(6);
}
return true;
}

return DeltaDecode(reader, channel.ScaleFactorDeltaBits, 6, channel.CodedScaleFactorCount, channel.ScaleFactors);
bool result = DeltaDecode(reader, channel.ScaleFactorDeltaBits, 6, codedScaleFactorCount, channel.ScaleFactors);
if (!result) return result;

// set derived HFR scales for v3.0
//FIXME UNTESTED
for (int i = 0; i < extraCodedScaleFactorCount; i++)
{
channel.HfrScales[codedScaleFactorCount - 1 - i] = channel.ScaleFactors[codedScaleFactorCount - i];
}

return result;
}

private static void ReadIntensity(BitReader reader, int[] intensity)
private static void ReadIntensity(BitReader reader, int[] intensity, int version)
{
for (int i = 0; i < SubframesPerFrame; i++)
if (version < 0x0300)
{
intensity[i] = reader.ReadInt(4);
for (int i = 0; i < SubframesPerFrame; i++)
{
intensity[i] = reader.ReadInt(4);
}
} else
{
//https://github.com/vgmstream/vgmstream/blob/4eecdada9a03a73af0c7c17f5cd6e08518fd7e3f/src/coding/hca_decoder_clhca.c#L1374
int value = reader.ReadInt(4);
int delta_bits;

if (value < 15)
{
delta_bits = reader.ReadInt(2); /* +1 */

intensity[0] = value;
if (delta_bits == 3)
{ /* 3+1 = 4b */
/* fixed intensities */
for (int i = 1; i < SubframesPerFrame; i++)
{
intensity[i] = reader.ReadInt(4);
}
}
else
{
/* delta intensities */
int bmax = (2 << delta_bits) - 1;
int bits = delta_bits + 1;

for (int i = 1; i < SubframesPerFrame; i++)
{
int delta = reader.ReadInt(bits);
if (delta == bmax)
{
value = reader.ReadInt(4); /* encoded */
}
else
{
value = value - (bmax >> 1) + delta; /* differential */
if (value > 15) //todo check
throw new InvalidDataException("value > 15"); /* not done in lib */
}

intensity[i] = value;
}
}
}
else
{
for (int i = 0; i < SubframesPerFrame; i++)
{
intensity[i] = 7;
}
}
}
}

Expand Down Expand Up @@ -194,6 +289,10 @@ private static bool DeltaDecode(BitReader reader, int deltaBits, int dataBits, i
{
return false;
}

// https://github.com/vgmstream/vgmstream/blob/4eecdada9a03a73af0c7c17f5cd6e08518fd7e3f/src/coding/hca_decoder_clhca.c#L1327
//value &= 0x3F; // v3.0 lib

output[i] = value;
}
else
Expand Down
1 change: 1 addition & 0 deletions src/VGAudio/Codecs/CriHca/HcaInfo.cs
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Expand Up @@ -4,6 +4,7 @@ namespace VGAudio.Codecs.CriHca
{
public class HcaInfo
{
public int Version { get; set; }
public int ChannelCount { get; set; }
public int SampleRate { get; set; }
public int SampleCount { get; set; }
Expand Down
1 change: 1 addition & 0 deletions src/VGAudio/Containers/Hca/HcaReader.cs
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Expand Up @@ -62,6 +62,7 @@ private static void ReadHcaHeader(BinaryReader reader, HcaStructure structure)
string signature = ReadChunkId(reader);
structure.Version = reader.ReadInt16();
structure.HeaderSize = reader.ReadInt16();
hca.Version = structure.Version;
hca.HeaderSize = structure.HeaderSize;

if (signature != "HCA\0")
Expand Down