public static byte[] wavToDPCMByte(byte[] data, uint dpcm_enc_lookahead = 3, bool loopEnabled = false, int loopStart = 0, int loopEnd = 0)
{
List <byte> wave = new List <byte>();
if (data[0] != 'R' ||
data[1] != 'I' ||
data[2] != 'F' ||
data[3] != 'F'
)
{
R.ShowStopError("Waveファイルではありません. RIFFヘッダがありません");
return(null);
}
if (data.Length < (44 + 1))
{
R.ShowStopError("Waveファイルではありません. データが小さすぎます");
return(null);
}
uint riff_chunk_size = U.u32(data, 4);
uint riff_form_type = U.u32(data, 8);
uint fmt_chunk_ID = U.u32(data, 12);
uint fmt_chunk_size = U.u32(data, 16);
uint fmt_wave_format_type = U.u16(data, 20);
uint fmt_channel = U.u16(data, 32);
uint fmt_samples_per_sec = U.u32(data, 24);
uint fmt_bytes_per_sec = U.u32(data, 28);
uint fmt_block_size = U.u16(data, 32);
uint fmt_bits_per_sample = U.u16(data, 34);
uint data_chunk_ID = U.u32(data, 36);
uint data_chunk_size = U.u32(data, 40);
if (data_chunk_size > data.Length - (44))
{//チャンクのデータサイズが不正だったら修正する.
data_chunk_size = (uint)(data.Length - (44));
}
if (data_chunk_size <= 1)
{
R.ShowStopError("Waveファイルではありません. data_chunk_size({0})が小さすぎます", data_chunk_size);
return(null);
}
PatchUtil.ImprovedSoundMixer withImprovedSoundMixer = PatchUtil.SearchImprovedSoundMixer();
if (fmt_bits_per_sample > 8)
{//サンプルビット数が8ビットを超える
R.ShowStopError("Waveファイルが高音質すぎます。{0}bit\r\n品質は、8bit 12khz monoぐらいにしてください。", fmt_bits_per_sample);
return(null);
}
U.append_u32(wave, 0x01); //圧縮フラグ 0x01 00 00 00
U.append_u32(wave, fmt_samples_per_sec * 1024); //周波数*1024
U.append_u32(wave, 0); //不明
U.append_u32(wave, data_chunk_size); //元のデータ長
if (loopEnabled)
{
if (loopEnd > data_chunk_size)
{
loopEnd = (int)data_chunk_size;
}
}
else
{//ループしない場合終端になります
loopEnd = (int)data_chunk_size;
}
int loop_sample = 0;
for (uint i = 0; i < loopEnd; i += DPCM_BLK_SIZE)
{
uint waveDataI = 44 + i;
byte[] wavBin = U.getBinaryData(data, waveDataI, DPCM_BLK_SIZE);
int[] ds = Add0x80(wavBin);
// check if loop end is inside this block
if (i + DPCM_BLK_SIZE > loopEnd)
{
Debug.Assert(loopEnd - i < DPCM_BLK_SIZE);
ds[loopEnd - i] = (byte)loop_sample;
}
// TODO apply dither noise
int s = ds[0];
if (loopEnabled && i == loopStart)
{
loop_sample = s;
}
U.append_u8(wave, (byte)(s & 0xFF));
//data_write(ofs, block_pos, s, false);
uint innerLoopCount = 1;
byte outData = 0;
while (innerLoopCount < DPCM_BLK_SIZE)
{
uint sampleBufReadLen = Math.Min(dpcm_enc_lookahead, DPCM_BLK_SIZE - innerLoopCount);
int minimumError;
uint minimumErrorIndex;
if (innerLoopCount != 1)
{//どういうわけか、最初の1バイトは特殊な格納方法をする
dpcm_lookahead(
out minimumError, out minimumErrorIndex,
ds, innerLoopCount, sampleBufReadLen, s);
outData = (byte)((minimumErrorIndex & 0xF) << 4);
s += dpcmLookupTable[minimumErrorIndex];
innerLoopCount += 1;
}
sampleBufReadLen = Math.Min(dpcm_enc_lookahead, DPCM_BLK_SIZE - innerLoopCount);
dpcm_lookahead(
out minimumError, out minimumErrorIndex,
ds, innerLoopCount, sampleBufReadLen, s);
outData |= (byte)(minimumErrorIndex & 0xF);
s += dpcmLookupTable[minimumErrorIndex];
innerLoopCount += 1;
U.append_u8(wave, (byte)(outData & 0xFF));
//data_write(ofs, block_pos, outData, true);
}
}
return(wave.ToArray());
}
