Author: Richard Funke

How do i write a wave file?

Answer:

1   type
2     TPCMWaveHeader = record
3       rID: array[0..3] of char; { 'RIFF' Identifier }
4       rLen: longint;
5       wID: array[0..3] of char; { 'WAVE' Identifier }
6       fId: array[0..3] of char; { 'fmt ' Identifier }
7       fLen: longint; { Fixed, must be 16 }
8       wFormatTag: word; { Fixed, must be 1 }
9       nChannels: word; { Mono=1, Stereo=2 }
10      nSamplesPerSec: longint; { SampleRate in Hertz }
11      nAvgBytesPerSec: longint;
12      nBlockAlign: word;
13      nBitsPerSample: word; { Resolution, e.g. 8 or 16 }
14      dId: array[0..3] of char; { 'data' Identifier }
15      dLen: longint; { Number of following data bytes }
16    end;
17  
18  procedure WritePCMWaveFile(Filename: string; Resolution, Channels, Samplerate,
19    Samples: integer; Data: Pointer);
20  var
21    h: TPCMWaveHeader;
22    f: file;
23    databytes: integer;
24  begin
25    DataBytes := Samples;
26    DataBytes := DataBytes * Channels; { double if stereo }
27    DataBytes := DataBytes * (Resolution div 8); { double if 16 Bit }
28  
29    FillChar(h, SizeOf(TPCMWaveHeader), #0);
30    with h do
31    begin
32      rID[0] := 'R';
33      rID[1] := 'I';
34      rID[2] := 'F';
35      rID[3] := 'F'; { 1st identifier }
36      rLen := DataBytes + 36;
37      wID[0] := 'W';
38      wID[1] := 'A';
39      wID[2] := 'V';
40      wID[3] := 'E'; { 2nd identifier }
41      fId[0] := 'f';
42      fId[1] := 'm';
43      fId[2] := 't';
44      fID[3] := Chr($20); { 3rdidentifier ends with a space character }
45      fLen := $10; { Fixed, must be 16 }
46      wFormatTag := 1; { Fixed, must be 1 }
47      nChannels := Channels; { Channels }
48      nSamplesPerSec := SampleRate; { Sample rate in Hertz }
49      nAvgBytesPerSec := SampleRate * Channels * trunc(Resolution div 8);
50      nBlockAlign := Channels * (Resolution div 8); { Byte order, see below }
51      nBitsPerSample := Resolution;
52      dId[0] := 'd';
53      dId[1] := 'a';
54      dId[2] := 't';
55      dId[3] := 'a'; { Data identifier }
56      dLen := DataBytes; { number of following data bytes }
57    end;
58    AssignFile(f, filename);
59    ReWrite(f, 1);
60    BlockWrite(f, h, SizeOf(h));
61    BlockWrite(f, pbytearray(data), databytes);
62    CloseFile(f);
63    { The rest of the file is the wave data. Order is low-high for left channel,
64        low-high for right channel, and so on.
65        For mono or 8 bit files make the respective changes. }
66  end;