WSS File Format: Difference between revisions
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else PCMData[j] = (j == 0) ? (Int16)0 : PCMData[j - 1]; | else PCMData[j] = (j == 0) ? (Int16)0 : PCMData[j - 1]; | ||
} | } | ||
[[Category:BIS_File_Formats]] | |||
Revision as of 02:13, 25 January 2010
Introduction
WSS files are used since OFP times to store sound data and its file format is pretty much like the RIFF WAVE file format used for .wav files.
File Format
| Offset | Datatype | Content | Description |
|---|---|---|---|
| 0 | char[4] | "WSS0" | file signature |
| 4 | ulong | <compression> | if <compression> == 8 the PCM data is compressed, otherwise <compression> == 0 |
| 8 | ushort | <format tag> | defines in which format the data is saved. Always 0x0001 in WSS files |
| 10 | ushort | <channels> | number of channels: 1=mono, 2=stereo |
| 12 | ulong | <sample rate> | sample rate in Hz (e.g. 44100Hz) |
| 16 | ulong | <bytes/second> | <sample rate> * <block align> |
| 20 | ushort | <block align> | <channels> * (<bits/sample> / 8) |
| 22 | ushort | <bits/sample> | usually 0x0010 in WSS files |
| 24 | ushort | <unknown> | unknown value |
| 26 | byte[fileSize-26] | <soundData> | here the PCM data of the sound is stored |
Decompression
If the <soundData> is compressed the following (C#) code can be used for decompression:
PCMData = new Int16[soundData.Length];
for (int j = 0; j < PCMData.Length; j++)
{
SByte srcSample = (SByte)soundData[j];
if (srcSample != 0)
{
double asFloat = Math.Abs(srcSample) / 28.12574042515172;
asFloat *= 2.3025850929940456840; //ln(10)
asFloat *= 1.4426950408889634070; //log2(e)
double rnd = Math.Round(asFloat);
double mantisse = Math.Pow(2.0, asFloat - rnd);
asFloat = mantisse * Math.Pow(2, rnd);
if (srcSample < 0) asFloat *= -1;
Int32 asInt = (int)Math.Round(asFloat);
asInt = (j == 0) ? asInt : (asInt + PCMData[j - 1]);
if (asInt > short.MaxValue) asInt = short.MaxValue;
if (asInt < short.MinValue) asInt = short.MinValue;
PCMData[j] = (Int16)asInt;
}
else PCMData[j] = (j == 0) ? (Int16)0 : PCMData[j - 1];
}