private static ChannelType[] GetChannelTypes(HcaInfo hca)
{
int channelsPerTrack = hca.ChannelCount / hca.TrackCount;
if (hca.StereoBandCount == 0 || channelsPerTrack == 1)
{
return(new ChannelType[8]);
}
switch (channelsPerTrack)
{
case 2: return(new[] { StereoPrimary, StereoSecondary });
case 3: return(new[] { StereoPrimary, StereoSecondary, Discrete });
case 4 when hca.ChannelConfig != 0: return(new[] { StereoPrimary, StereoSecondary, Discrete, Discrete });
case 4 when hca.ChannelConfig == 0: return(new[] { StereoPrimary, StereoSecondary, StereoPrimary, StereoSecondary });
case 5 when hca.ChannelConfig > 2: return(new[] { StereoPrimary, StereoSecondary, Discrete, Discrete, Discrete });
case 5 when hca.ChannelConfig <= 2: return(new[] { StereoPrimary, StereoSecondary, Discrete, StereoPrimary, StereoSecondary });
case 6: return(new[] { StereoPrimary, StereoSecondary, Discrete, Discrete, StereoPrimary, StereoSecondary });
case 7: return(new[] { StereoPrimary, StereoSecondary, Discrete, Discrete, StereoPrimary, StereoSecondary, Discrete });
case 8: return(new[] { StereoPrimary, StereoSecondary, Discrete, Discrete, StereoPrimary, StereoSecondary, StereoPrimary, StereoSecondary });
default: return(new ChannelType[channelsPerTrack]);
}
}
public static void Crypt(HcaInfo hca, byte[][] audio, CriHcaKey key, bool doDecrypt)
{
for (int frame = 0; frame < hca.FrameCount; frame++)
{
CryptFrame(hca, audio[frame], key, doDecrypt);
}
}
public static void DecryptFrame(HcaInfo hca, byte[] audio, CriHcaKey key)
{
for (int b = 0; b < hca.FrameSize; b++)
{
audio[b] = key.DecryptionTable[audio[b]];
}
}
/// <summary>
/// Initializes this <see cref="CriHcaEncoder"/>. Any preexisting state is reset, and the encoder
/// will be ready to accept PCM audio via <see cref="Encode"/>.
/// </summary>
/// <param name="config">The configuration to be used when creating the HCA file.</param>
public void Initialize(CriHcaParameters config)
{
if (config.ChannelCount > 8)
{
throw new ArgumentOutOfRangeException(nameof(config.ChannelCount), "HCA channel count must be 8 or below");
}
CutoffFrequency = config.SampleRate / 2;
Quality = config.Quality;
PostSamples = 128;
Hca = new HcaInfo
{
ChannelCount = config.ChannelCount,
TrackCount = 1,
SampleCount = config.SampleCount,
SampleRate = config.SampleRate,
MinResolution = 1,
MaxResolution = 15,
InsertedSamples = SamplesPerSubFrame
};
Bitrate = CalculateBitrate(Hca, Quality, config.Bitrate, config.LimitBitrate);
CalculateBandCounts(Hca, Bitrate, CutoffFrequency);
Hca.CalculateHfrValues();
SetChannelConfiguration(Hca);
int inputSampleCount = Hca.SampleCount;
if (config.Looping)
{
Hca.Looping = true;
Hca.SampleCount = Math.Min(config.LoopEnd, config.SampleCount);
Hca.InsertedSamples += GetNextMultiple(config.LoopStart, SamplesPerFrame) - config.LoopStart;
CalculateLoopInfo(Hca, config.LoopStart, config.LoopEnd);
inputSampleCount = Math.Min(GetNextMultiple(Hca.SampleCount, SamplesPerSubFrame), config.SampleCount);
inputSampleCount += SamplesPerSubFrame * 2;
PostSamples = inputSampleCount - Hca.SampleCount;
}
CalculateHeaderSize(Hca);
int totalSamples = inputSampleCount + Hca.InsertedSamples;
Hca.FrameCount = totalSamples.DivideByRoundUp(SamplesPerFrame);
Hca.AppendedSamples = Hca.FrameCount * SamplesPerFrame - Hca.InsertedSamples - inputSampleCount;
Frame = new CriHcaFrame(Hca);
Channels = Frame.Channels;
PcmBuffer = CreateJaggedArray <short[][]>(Hca.ChannelCount, SamplesPerFrame);
PostAudio = CreateJaggedArray <short[][]>(Hca.ChannelCount, PostSamples);
HcaOutputBuffer = new Queue <byte[]>();
BufferPreSamples = Hca.InsertedSamples - 128;
}
public static void CryptFrame(HcaInfo hca, byte[] audio, CriHcaKey key, bool doDecrypt)
{
byte[] substitutionTable = doDecrypt ? key.DecryptionTable : key.EncryptionTable;
for (int b = 0; b < hca.FrameSize - 2; b++)
{
audio[b] = substitutionTable[audio[b]];
}
ushort crc = Crc.Compute(audio, hca.FrameSize - 2);
audio[hca.FrameSize - 2] = (byte)(crc >> 8);
audio[hca.FrameSize - 1] = (byte)crc;
}
public static CriHcaKey FindKey(HcaInfo hca, byte[][] audio)
{
var frame = new CriHcaFrame(hca);
var buffer = new byte[hca.FrameSize];
foreach (CriHcaKey key in Keys)
{
if (TestKey(frame, audio, key, buffer))
{
return(key);
}
}
return(null);
}
private static void SetChannelConfiguration(HcaInfo hca, int channelConfig = -1)
{
int channelsPerTrack = hca.ChannelCount / hca.TrackCount;
if (channelConfig == -1)
{
channelConfig = CriHcaTables.DefaultChannelMapping[channelsPerTrack];
}
if (CriHcaTables.ValidChannelMappings[channelsPerTrack - 1][channelConfig] != 1)
{
throw new ArgumentOutOfRangeException(nameof(channelConfig), "Channel mapping is not valid.");
}
hca.ChannelConfig = channelConfig;
}
private static void CalculateLoopInfo(HcaInfo hca, int loopStart, int loopEnd)
{
loopStart += hca.InsertedSamples;
loopEnd += hca.InsertedSamples;
hca.LoopStartFrame = loopStart / SamplesPerFrame;
hca.PreLoopSamples = loopStart % SamplesPerFrame;
hca.LoopEndFrame = loopEnd / SamplesPerFrame;
hca.PostLoopSamples = SamplesPerFrame - loopEnd % SamplesPerFrame;
if (hca.PostLoopSamples == SamplesPerFrame)
{
hca.LoopEndFrame--;
hca.PostLoopSamples = 0;
}
}
private static void CalculateHfrScale(CriHcaFrame frame)
{
HcaInfo hca = frame.Hca;
if (hca.HfrGroupCount == 0)
{
return;
}
int hfrStartBand = hca.StereoBandCount + hca.BaseBandCount;
int hfrBandCount = Math.Min(hca.HfrBandCount, hca.TotalBandCount - hca.HfrBandCount);
foreach (CriHcaChannel channel in frame.Channels)
{
if (channel.Type == ChannelType.StereoSecondary)
{
continue;
}
double[] groupSpectra = channel.HfrGroupAverageSpectra;
for (int group = 0, band = 0; group < hca.HfrGroupCount; group++)
{
double sum = 0.0;
int count = 0;
for (int i = 0; i < hca.BandsPerHfrGroup && band < hfrBandCount; band++, i++)
{
for (int subframe = 0; subframe < SubframesPerFrame; subframe++)
{
sum += Math.Abs(channel.ScaledSpectra[hfrStartBand - band - 1][subframe]);
}
count += SubframesPerFrame;
}
double averageSpectra = sum / count;
if (averageSpectra > 0.0)
{
groupSpectra[group] *= Math.Min(1.0 / averageSpectra, Math.Sqrt(2));
}
channel.HfrScales[group] = FindScaleFactor(groupSpectra[group]);
}
}
}
public static short[][] Decode(HcaInfo hca, byte[][] audio, CriHcaParameters config = null)
{
config?.Progress?.SetTotal(hca.FrameCount);
var pcmOut = Helpers.CreateJaggedArray <short[][]>(hca.ChannelCount, hca.SampleCount);
var pcmBuffer = Helpers.CreateJaggedArray <short[][]>(hca.ChannelCount, SamplesPerFrame);
var frame = new CriHcaFrame(hca);
for (int i = 0; i < hca.FrameCount; i++)
{
DecodeFrame(audio[i], frame, pcmBuffer);
CopyPcmToOutput(pcmBuffer, pcmOut, hca, i);
//CopyBuffer(pcmBuffer, pcmOut, hca.InsertedSamples, i);
config?.Progress?.ReportAdd(1);
}
return(pcmOut);
}
private static void CopyPcmToOutput(short[][] pcmIn, short[][] pcmOut, HcaInfo hca, int frame)
{
int currentSample = frame * SamplesPerFrame - hca.InsertedSamples;
int remainingSamples = Math.Min(hca.SampleCount - currentSample, hca.SampleCount);
int srcStart = Helpers.Clamp(0 - currentSample, 0, SamplesPerFrame);
int destStart = Math.Max(currentSample, 0);
int length = Math.Min(SamplesPerFrame - srcStart, remainingSamples);
if (length <= 0)
{
return;
}
for (int c = 0; c < pcmOut.Length; c++)
{
Array.Copy(pcmIn[c], srcStart, pcmOut[c], destStart, length);
}
}
public CriHcaFrame(HcaInfo hca)
{
Hca = hca;
ChannelType[] channelTypes = GetChannelTypes(hca);
Channels = new CriHcaChannel[hca.ChannelCount];
for (int i = 0; i < Channels.Length; i++)
{
Channels[i] = new CriHcaChannel
{
Type = channelTypes[i],
CodedScaleFactorCount = channelTypes[i] == StereoSecondary
? hca.BaseBandCount
: hca.BaseBandCount + hca.StereoBandCount
};
}
AthCurve = hca.UseAthCurve ? ScaleAthCurve(hca.SampleRate) : new byte[SamplesPerSubFrame];
}
private static void CalculateHeaderSize(HcaInfo hca)
{
const int baseHeaderSize = 96;
const int baseHeaderAlignment = 32;
const int loopFrameAlignment = 2048;
hca.HeaderSize = GetNextMultiple(baseHeaderSize + hca.CommentLength, baseHeaderAlignment);
if (hca.Looping)
{
int loopFrameOffset = hca.HeaderSize + hca.FrameSize * hca.LoopStartFrame;
int paddingBytes = GetNextMultiple(loopFrameOffset, loopFrameAlignment) - loopFrameOffset;
int paddingFrames = paddingBytes / hca.FrameSize;
hca.InsertedSamples += paddingFrames * SamplesPerFrame;
hca.LoopStartFrame += paddingFrames;
hca.LoopEndFrame += paddingFrames;
hca.HeaderSize += paddingBytes % hca.FrameSize;
}
}
private static void CalculateBandCounts(HcaInfo hca, int bitrate, int cutoffFreq)
{
hca.FrameSize = bitrate * 1024 / hca.SampleRate / 8;
int numGroups = 0;
int pcmBitrate = hca.SampleRate * hca.ChannelCount * 16;
int hfrRatio; // HFR is used at bitrates below (pcmBitrate / hfrRatio)
int cutoffRatio; // The cutoff frequency is lowered at bitrates below (pcmBitrate / cutoffRatio)
if (hca.ChannelCount <= 1 || pcmBitrate / bitrate <= 6)
{
hfrRatio = 6;
cutoffRatio = 12;
}
else
{
hfrRatio = 8;
cutoffRatio = 16;
}
if (bitrate < pcmBitrate / cutoffRatio)
{
cutoffFreq = Math.Min(cutoffFreq, cutoffRatio * bitrate / (32 * hca.ChannelCount));
}
int totalBandCount = (int)Math.Round(cutoffFreq * 256.0 / hca.SampleRate);
int hfrStartBand = (int)Math.Min(totalBandCount, Math.Round((hfrRatio * bitrate * 128.0) / pcmBitrate));
int stereoStartBand = hfrRatio == 6 ? hfrStartBand : (hfrStartBand + 1) / 2;
int hfrBandCount = totalBandCount - hfrStartBand;
int bandsPerGroup = hfrBandCount.DivideByRoundUp(8);
if (bandsPerGroup > 0)
{
numGroups = hfrBandCount.DivideByRoundUp(bandsPerGroup);
}
hca.TotalBandCount = totalBandCount;
hca.BaseBandCount = stereoStartBand;
hca.StereoBandCount = hfrStartBand - stereoStartBand;
hca.HfrGroupCount = numGroups;
hca.BandsPerHfrGroup = bandsPerGroup;
}
private int CalculateBitrate(HcaInfo hca, CriHcaQuality quality, int bitrate, bool limitBitrate)
{
int pcmBitrate = Hca.SampleRate * Hca.ChannelCount * 16;
int maxBitrate = pcmBitrate / 4;
int minBitrate = 0;
int compressionRatio = 6;
switch (quality)
{
case CriHcaQuality.Highest:
compressionRatio = 4;
break;
case CriHcaQuality.High:
compressionRatio = 6;
break;
case CriHcaQuality.Middle:
compressionRatio = 8;
break;
case CriHcaQuality.Low:
compressionRatio = hca.ChannelCount == 1 ? 10 : 12;
break;
case CriHcaQuality.Lowest:
compressionRatio = hca.ChannelCount == 1 ? 12 : 16;
break;
}
bitrate = bitrate != 0 ? bitrate : pcmBitrate / compressionRatio;
if (limitBitrate)
{
minBitrate = Math.Min(
hca.ChannelCount == 1 ? 42666 : 32000 * hca.ChannelCount,
pcmBitrate / 6);
}
return(Clamp(bitrate, minBitrate, maxBitrate));
}
private static void ReconstructHighFrequency(CriHcaFrame frame)
{
HcaInfo hca = frame.Hca;
if (hca.HfrGroupCount == 0)
{
return;
}
// The last spectral coefficient should always be 0;
int totalBandCount = Math.Min(hca.TotalBandCount, 127);
int hfrStartBand = hca.BaseBandCount + hca.StereoBandCount;
int hfrBandCount = Math.Min(hca.HfrBandCount, totalBandCount - hca.HfrBandCount);
foreach (CriHcaChannel channel in frame.Channels)
{
if (channel.Type == ChannelType.StereoSecondary)
{
continue;
}
for (int group = 0, band = 0; group < hca.HfrGroupCount; group++)
{
for (int i = 0; i < hca.BandsPerHfrGroup && band < hfrBandCount; band++, i++)
{
int highBand = hfrStartBand + band;
int lowBand = hfrStartBand - band - 1;
int index = channel.HfrScales[group] - channel.ScaleFactors[lowBand] + 64;
for (int sf = 0; sf < SubframesPerFrame; sf++)
{
channel.Spectra[sf][highBand] = ScaleConversionTable[index] * channel.Spectra[sf][lowBand];
}
}
}
}
}
private static void CalculateHfrGroupAverages(CriHcaFrame frame)
{
HcaInfo hca = frame.Hca;
if (hca.HfrGroupCount == 0)
{
return;
}
int hfrStartBand = hca.StereoBandCount + hca.BaseBandCount;
foreach (CriHcaChannel channel in frame.Channels)
{
if (channel.Type == ChannelType.StereoSecondary)
{
continue;
}
for (int group = 0, band = hfrStartBand; group < hca.HfrGroupCount; group++)
{
double sum = 0.0;
int count = 0;
for (int i = 0; i < hca.BandsPerHfrGroup && band < SamplesPerSubFrame; band++, i++)
{
for (int subframe = 0; subframe < SubframesPerFrame; subframe++)
{
sum += Math.Abs(channel.Spectra[subframe][band]);
}
count += SubframesPerFrame;
}
channel.HfrGroupAverageSpectra[group] = sum / count;
}
}
}