*.XA loading + decompressing

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SoCoder -> Snippet Home -> File Access

Afr0	Created : 26 July 2009 Edited : 11 December 2009 System : Windows Language : C/C++ *.XA loading + decompressing Load sounds from Maxis games!
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.IO; using System.Media; namespace SimsLib.XA { public enum SoundType { Mono = 0x00, Stereo = 0x01 } public class XAFile { private int m_CurSampleLeft = 0; private int m_PrevSampleLeft = 0; private int m_CurSampleRight = 0; private int m_PrevSampleRight = 0; BinaryReader m_Reader; BinaryWriter m_Writer; MemoryStream m_DecompressedStream; // Note that the part of the header from (wTag) until //(wBits) is really WAVEFORMATEX structure (the contents of PCM .WAV fmt chunk). private string m_ID = ""; //string ID, which is equal to "XAI\0" (sound/speech) or "XAJ\0" (music). private uint m_DecompressedSize; //the output size of the audio stream stored in the file (in bytes). private ushort m_Tag; //seems to be PCM waveformat tag (0x0001). This corresponds to the (decompressed) output audio stream, of course. private ushort m_Channels; //number of channels for the file. private uint m_SampleRate; //sample rate for the file. private uint m_AvgByteRate; //average byte rate for the file (equal to (dwSampleRate)(wAlign)). Note that this also corresponds to the decompressed output audio stream. private ushort m_Align; //the sample align value for the file (equal to (wBits/8)(wChannels)). Again, this corresponds to the decompressed output audio stream. private ushort m_Bits; //resolution of the file (8 (8-bit), 16 (16-bit), etc.). /// <summary> /// The decompressed wave data as a byte array. /// Will not contain any data unless DecompressFile() has been called! /// </summary> public byte[] DecompressedData { get { return m_DecompressedStream.ToArray(); } } /// <summary> /// The decompressed wave data as a MemoryStream instance. /// Will not contain any data unless DecompressFile() has been called! /// </summary> public MemoryStream DecompressedStream { get { m_DecompressedStream.Position = 0; return m_DecompressedStream; } } /// <summary> /// Loads and an .xa file, setting things up for decompression. /// Should always be called before DecompressFile(). /// </summary> /// <param name="Path">The path to the .xa file to load.</param> public void LoadFile(string Path) { m_Reader = new BinaryReader(File.Open(Path, FileMode.Open)); m_ID = new string(m_Reader.ReadChars(4)); m_DecompressedSize = m_Reader.ReadUInt32(); m_Tag = m_Reader.ReadUInt16(); m_Channels = m_Reader.ReadUInt16(); m_SampleRate = m_Reader.ReadUInt32(); m_AvgByteRate = m_Reader.ReadUInt32(); m_Align = m_Reader.ReadUInt16(); m_Bits = m_Reader.ReadUInt16(); m_DecompressedStream = new MemoryStream(); m_Writer = new BinaryWriter(m_DecompressedStream); } /// <summary> /// Loads and an .xa file, setting things up for decompression. /// Should always be called before DecompressFile(). /// </summary> /// <param name="Data">The data of the .xa file to process.</param> public void LoadFile(byte[] Data) { m_Reader = new BinaryReader(new MemoryStream(Data)); m_ID = new string(m_Reader.ReadChars(4)); m_DecompressedSize = m_Reader.ReadUInt32(); m_Tag = m_Reader.ReadUInt16(); m_Channels = m_Reader.ReadUInt16(); m_SampleRate = m_Reader.ReadUInt32(); m_AvgByteRate = m_Reader.ReadUInt32(); m_Align = m_Reader.ReadUInt16(); m_Bits = m_Reader.ReadUInt16(); m_DecompressedStream = new MemoryStream(); m_Writer = new BinaryWriter(m_DecompressedStream); } /// <summary> /// Decompresses the sounddata and stores it in the the decompressed stream in this class. /// </summary> public void DecompressFile() { uint dwDataSize = /((m_DecompressedSize - 24) - (m_DecompressedSize - 24) / 15) 4;/m_DecompressedSize; uint dwFMTSize = 16; uint dwRIFFSize = /dwFMTSize + 8 + dwDataSize + 8 + 4;/ dwDataSize + 4 + 4 + dwFMTSize + 4 + 9; m_Writer.Write(new char[] { 'R', 'I', 'F', 'F' }); m_Writer.Write(dwRIFFSize); //Size of file minus this field and the above field. m_Writer.Write(new char[] { 'W', 'A', 'V', 'E', 'f', 'm', 't', ' ' }); m_Writer.Write(dwFMTSize); //Size of WAVEFORMATEX structure (all the data that comes after this field). m_Writer.Write(m_Tag); m_Writer.Write(m_Channels); m_Writer.Write(m_SampleRate); m_Writer.Write(m_AvgByteRate); m_Writer.Write(m_Align); m_Writer.Write(m_Bits); m_Writer.Write(new char[] { 'd', 'a', 't', 'a' }); m_Writer.Write(dwDataSize); if (m_Channels == 1) //Mono { while (m_Reader.BaseStream.Position < m_Reader.BaseStream.Length) { DecompressMono(m_Reader.ReadBytes(0xF)); } } else if (m_Channels == 2) //Stereo { while (m_Reader.BaseStream.Position < m_Reader.BaseStream.Length) { DecompressStereo(m_Reader.ReadBytes(0x1E)); } } /SoundPlayer Player = new SoundPlayer(); Player.Stream = m_DecompressedStream; Player.Play();/ BinaryWriter FileWriter = new BinaryWriter(File.Create("C:\\test.wav")); FileWriter.Write(m_DecompressedStream.ToArray()); FileWriter.Close(); } private void DecompressStereo(byte[] InputBuffer) { //BYTE InputBuffer[InputBufferSize]; // buffer containing data for one block byte bInput; uint i; int c1left,c2left,c1right,c2right,left,right; byte dleft, dright; bInput=InputBuffer[0]; c1left=(int)EATable[HINIBBLE(bInput)]; // predictor coeffs for left channel c2left = (int)EATable[HINIBBLE(bInput) + 4]; dleft=(byte)(LONIBBLE(bInput)+8); // shift value for left channel bInput=InputBuffer[1]; c1right = (int)EATable[HINIBBLE(bInput)]; // predictor coeffs for right channel c2right = (int)EATable[HINIBBLE(bInput) + 4]; dright=(byte)(LONIBBLE(bInput)+8); // shift value for right channel for (i=2;i<0x1E;i+=2) { left=HINIBBLE(InputBuffer[i]); // HIGHER nibble for left channel left=(left<<0x1c)>>dleft; left = (left + m_CurSampleLeft c1left + m_PrevSampleLeft * c2left + 0x80) >> 8; left=Clip16BitSample(left); m_PrevSampleLeft = m_CurSampleLeft; m_CurSampleLeft = left; right=HINIBBLE(InputBuffer[i+1]); // HIGHER nibble for right channel right=(right<<0x1c)>>dright; right = (right + m_CurSampleRight * c1right + m_PrevSampleRight * c2right + 0x80) >> 8; right=Clip16BitSample(right); m_PrevSampleRight = m_CurSampleLeft; m_CurSampleRight = right; // Now we've got lCurSampleLeft and lCurSampleRight which form one stereo // sample and all is set for the next step... //Output((SHORT)lCurSampleLeft,(SHORT)lCurSampleRight); // send the sample to output m_Writer.Write((short)m_CurSampleLeft); m_Writer.Write((short)m_CurSampleRight); // now do just the same for LOWER nibbles... // note that nubbles for each channel are packed pairwise into one byte left=LONIBBLE(InputBuffer[i]); // LOWER nibble for left channel left=(left<<0x1c)>>dleft; left = (left + m_CurSampleLeft * c1left + m_PrevSampleLeft * c2left + 0x80) >> 8; left=Clip16BitSample(left); m_PrevSampleLeft = m_CurSampleLeft; m_CurSampleLeft = left; right=LONIBBLE(InputBuffer[i+1]); // LOWER nibble for right channel right=(right<<0x1c)>>dright; right = (right + m_CurSampleRight * c1right + m_PrevSampleRight * c2right + 0x80) >> 8; right=Clip16BitSample(right); m_PrevSampleRight = m_CurSampleRight; m_CurSampleRight = right; // Now we've got lCurSampleLeft and lCurSampleRight which form one stereo // sample and all is set for the next step... //Output((SHORT)lCurSampleLeft,(SHORT)lCurSampleRight); // send the sample to output m_Writer.Write((short)m_CurSampleLeft); m_Writer.Write((short)m_CurSampleRight); } } private void DecompressMono(byte[] InputBuffer) { byte bInput = InputBuffer[0]; uint i; int c1 = (int)EATable[HINIBBLE(bInput)]; // predictor coeffs int c2 = (int)EATable[HINIBBLE(bInput) + 4]; int left, c1left, c2left; byte d, dleft; d = (byte)(LONIBBLE(bInput) + 8); // shift value c1left = (int)EATable[HINIBBLE(bInput)]; // predictor coeffs for left channel c2left = (int)EATable[HINIBBLE(bInput) + 4]; dleft = (byte)(LONIBBLE(bInput) + 8); // shift value for left channel for (i = 1; i < 0xF; i++) { left = HINIBBLE(InputBuffer[i]); // HIGHER nibble for left channel left = (left << 0x1c) >> dleft; left = (left + m_CurSampleLeft * c1left + m_PrevSampleLeft * c2left + 0x80) >> 8; left = Clip16BitSample(left); m_PrevSampleLeft = m_CurSampleLeft; m_CurSampleLeft = left; // Now we've got lCurSampleLeft which is one mono sample and all is set // for the next input nibble... //Output((SHORT)lCurSampleLeft); // send the sample to output m_Writer.Write((short)m_CurSampleLeft); left = LONIBBLE(InputBuffer[i]); // LOWER nibble for left channel left = (left << 0x1c) >> dleft; left = (left + m_CurSampleLeft * c1left + m_PrevSampleLeft * c2left + 0x80) >> 8; left = Clip16BitSample(left); m_PrevSampleLeft = m_CurSampleLeft; m_CurSampleLeft = left; // Now we've got lCurSampleLeft which is one mono sample and all is set // for the next input byte... //Output((SHORT)lCurSampleLeft); // send the sample to output m_Writer.Write((short)m_CurSampleLeft); } } private int Clip16BitSample(int sample) { if (sample > 32767) return 32767; else if (sample < -32768) return (-32768); else return sample; } private byte HINIBBLE(byte B) { return (byte)(((B) >> 4) & 0x0F); } private byte LONIBBLE(byte B) { return (byte)((B) & 0x0F); } private long[] EATable = { 0x00000000, 0x000000F0, 0x000001CC, 0x00000188, 0x00000000, 0x00000000, 0xFFFFFF30, 0xFFFFFF24, 0x00000000, 0x00000001, 0x00000003, 0x00000004, 0x00000007, 0x00000008, 0x0000000A, 0x0000000B, 0x00000000, 0xFFFFFFFF, 0xFFFFFFFD, 0xFFFFFFFC }; } } --v Credits: The decompression functions were ported to C# from this code.

Comments
Sunday, 26 July 2009, 12:52
Afr0	If you are going to port this, note that longs are 64 bits in C#, and have thusly been replaced with ints in this code. In C++, you'd normally use long instead. Also note that this class is designed to inflate the compressed data in memory. You could also write the inflated data directly to a file, though this is not recommended for realtime use!
Sunday, 26 July 2009, 13:07
Phoenix	In C++ you'd have to use some preprocessor macros to get exactly 64 bits (if possible), or long longs to get at least 64 bits in the integer. I'm not sure how useful this is for the rest of us who aren't interested in remaking The Sims Online, but it looks like some decent working code.
Sunday, 26 July 2009, 13:19
JL235	It's MS only, but there is also __int64.
Sunday, 26 July 2009, 14:15
Afr0	No, no! Longs are 32 bits in C++, and are stored as 32 bits in XA files and Wav files. So you should treat them as 32 bits. Oh and XA files are used in all Maxis games from Sim City 3000 onwards. I believe there is even an early version of *.xa used in Sim City 2000, but I've never actually opened any of those data files.
Sunday, 26 July 2009, 14:31
Phoenix	sigh We already had this discussion in the chat a while ago. In C++, things aren't that simple. There are no guarantees that an int is 32 bits, or even that a char is 8 bits.
Monday, 27 July 2009, 00:55
cthug	You could use SDL types (Uint32, Uint8 etc)
Friday, 31 July 2009, 17:20
Afr0	I'm not sure if the original code is designed to be compiled as C or C++, but it seems to be using the Microsoft specific types like LONG, BYTE and DWORD. These are, IIRC, defined in Windows.h, and should be confined to 'general' standards like LONG = 32 bits and BYTE is 8 bits. See the link in the original post for reference.

*.XA loading + decompressing

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