unit W32Waves; 
{ Unit for accessing Windows PCM wave file informations 
 By Ulli Conrad <uconrad@gmx.net> } 

interface 

uses SysUtils, Windows, MMSystem, Dialogs; 

type 
 PWaveInformation = ^tWaveInformation; 
 TWaveInformation = record 
 WaveFormat: Word; { Wave format identifier } 
 Channels: Word; { Mono=1, Stereo=2 } 
 SampleRate: Longint; { Sample rate in Hertz } 
 BitsPerSample: Word; { Resolution, e.g. 8 or 16 Bit } 
 SamplesNumber: Longint; { Number of samples } 
 Length: Extended; { Sample length in seconds } 
 ValidWave: bool; { Specifies if the file could be read } 
 end; 

const { Constants for wave format identifier } 
 WAVE_FORMAT_PCM = $0001; { Windows PCM } 
 WAVE_FORMAT_G723_ADPCM = $0014; { Antex ADPCM } 
 WAVE_FORMAT_ANTEX_ADPCME = $0033; { Antex ADPCME } 
 WAVE_FORMAT_G721_ADPCM = $0040; { Antex ADPCM } 
 WAVE_FORMAT_APTX = $0025; { Audio Processing Technology } 
 WAVE_FORMAT_AUDIOFILE_AF36 = $0024; { Audiofile, Inc. } 
 WAVE_FORMAT_AUDIOFILE_AF10 = $0026; { Audiofile, Inc. } 
 WAVE_FORMAT_CONTROL_RES_VQLPC = $0034; { Control Resources Limited } 
 WAVE_FORMAT_CONTROL_RES_CR10 = $0037; { Control Resources Limited } 
 WAVE_FORMAT_CREATIVE_ADPCM = $0200; { Creative ADPCM } 
 WAVE_FORMAT_DOLBY_AC2 = $0030; { Dolby Laboratories } 
 WAVE_FORMAT_DSPGROUP_TRUESPEECH = $0022; { DSP Group, Inc } 
 WAVE_FORMAT_DIGISTD = $0015; { DSP Solutions, Inc. } 
 WAVE_FORMAT_DIGIFIX = $0016; { DSP Solutions, Inc. } 
 WAVE_FORMAT_DIGIREAL = $0035; { DSP Solutions, Inc. } 
 WAVE_FORMAT_DIGIADPCM = $0036; { DSP Solutions ADPCM } 
 WAVE_FORMAT_ECHOSC1 = $0023; { Echo Speech Corporation } 
 WAVE_FORMAT_FM_TOWNS_SND = $0300; { Fujitsu Corp. } 
 WAVE_FORMAT_IBM_CVSD = $0005; { IBM Corporation } 
 WAVE_FORMAT_OLIGSM = $1000; { Ing C. Olivetti & C., S.p.A. } 
 WAVE_FORMAT_OLIADPCM = $1001; { Ing C. Olivetti & C., S.p.A. } 
 WAVE_FORMAT_OLICELP = $1002; { Ing C. Olivetti & C., S.p.A. } 
 WAVE_FORMAT_OLISBC = $1003; { Ing C. Olivetti & C., S.p.A. } 
 WAVE_FORMAT_OLIOPR = $1004; { Ing C. Olivetti & C., S.p.A. } 
 WAVE_FORMAT_IMA_ADPCM = $0011; { Intel ADPCM } 
 WAVE_FORMAT_DVI_ADPCM = $0011; { Intel ADPCM } 
 WAVE_FORMAT_UNKNOWN = $0000; 
 WAVE_FORMAT_ADPCM = $0002; { Microsoft ADPCM } 
 WAVE_FORMAT_ALAW = $0006; { Microsoft Corporation } 
 WAVE_FORMAT_MULAW = $0007; { Microsoft Corporation } 
 WAVE_FORMAT_GSM610 = $0031; { Microsoft Corporation } 
 WAVE_FORMAT_MPEG = $0050; { Microsoft Corporation } 
 WAVE_FORMAT_NMS_VBXADPCM = $0038; { Natural MicroSystems ADPCM } 
 WAVE_FORMAT_OKI_ADPCM = $0010; { OKI ADPCM } 
 WAVE_FORMAT_SIERRA_ADPCM = $0013; { Sierra ADPCM } 
 WAVE_FORMAT_SONARC = $0021; { Speech Compression } 
 WAVE_FORMAT_MEDIASPACE_ADPCM = $0012; { Videologic ADPCM } 
 WAVE_FORMAT_YAMAHA_ADPCM = $0020; { Yamaha ADPCM } 

function GetWaveInformationFromFile(FileName: string; Info: pWaveInformation): bool; 

implementation 

type 
 TCommWaveFmtHeader = record 
 wFormatTag: Word; { Fixed, must be 1 } 
 nChannels: Word; { Mono=1, Stereo=2 } 
 nSamplesPerSec: Longint; { SampleRate in Hertz } 
 nAvgBytesPerSec: Longint; 
 nBlockAlign: Word; 
 nBitsPerSample: Word; { Resolution, e.g. 8 or 16 } 
 cbSize: Longint; { Size of extra information in the extended fmt Header } 
 end; 

function GetWaveInformationFromFile(FileName: string; Info: pWaveInformation): bool; 
var 
 hdmmio: HMMIO; 
 mmckinfoParent: TMMCKInfo; 
 mmckinfoSubchunk: TMMCKInfo; 
 Fmt: TCommWaveFmtHeader; 
 Samples: Longint; 
begin 
 Result := False; 
 FillChar(Info^, SizeOf(TWaveInformation), #0); { Initialize first } 
 hdmmio := mmioOpen(PChar(FileName), nil, MMIO_READ); 
 if (hdmmio = 0) then 
 Exit; 
 {* Locate a 'RIFF' chunk with a 'WAVE' form type 
 * to make sure it's a WAVE file. 
 *} 
 mmckinfoParent.fccType := mmioStringToFOURCC('WAVE', MMIO_TOUPPER); 
 if (mmioDescend(hdmmio, PMMCKINFO(@mmckinfoParent), nil, MMIO_FINDRIFF) <> 0) then 
 Exit; 
 {* Now, find the format chunk (form type 'fmt '). It should be 
 * a subchunk of the 'RIFF' parent chunk. 
 *} 
 mmckinfoSubchunk.ckid := mmioStringToFOURCC('fmt ', 0); 
 if (mmioDescend(hdmmio, @mmckinfoSubchunk, @mmckinfoParent, MMIO_FINDCHUNK) <> 0) then 
 Exit; 

 // Read the format chunk. 
 if (mmioRead(hdmmio, PChar(@fmt), Longint(SizeOf(TCommWaveFmtHeader))) <> 
 Longint(SizeOf(TCommWaveFmtHeader))) then 
 Exit; 
 Info^.WaveFormat := fmt.wFormatTag; 
 Info^.Channels := fmt.nChannels; 
 Info^.SampleRate := fmt.nSamplesPerSec; 
 Info^.BitsPerSample := fmt.nBitsPerSample; 
 mmioAscend(hdmmio, @mmckinfoSubchunk, 0); // Ascend out of the format subchunk. 
 mmckinfoSubchunk.ckid := mmioStringToFOURCC('data', 0); // Find the data subchunk. 
 if (mmioDescend(hdmmio, @mmckinfoSubchunk, @mmckinfoParent, MMIO_FINDCHUNK) <> 0) then 
 Exit; 
 Info^.SamplesNumber := mmckinfoSubchunk.cksize; // Get the size of the data subchunk. 

 Samples := (Info^.SamplesNumber * 8 * Info^.Channels) div Info^.BitsPerSample; 
 Info^.Length := Samples / Info^.Samplerate; 
 mmioClose(hdmmio, 0); // We're done with the file, close it. 
 Info^.ValidWave := True; 
 Result := True; 
end; 
end.