Как прочитать заголовок wav файла?
Falk0ner, вс, 06/07/2008 - 15:35.
type
TWaveHeader = record
ident1: array[0..3] of Char; // Must be "RIFF"
len: DWORD; // Remaining length after this header
ident2: array[0..3] of Char; // Must be "WAVE"
ident3: array[0..3] of Char; // Must be "fmt "
reserv: DWORD; // Reserved 4 bytes
wFormatTag: Word; // format type
nChannels: Word; // number of channels (i.e. mono, stereo, etc.)
nSamplesPerSec: DWORD; //sample rate
nAvgBytesPerSec: DWORD; //for buffer estimation
nBlockAlign: Word; //block size of data
wBitsPerSample: Word; //number of bits per sample of mono data
cbSize: Word; //the count in bytes of the size of
ident4: array[0..3] of Char; //Must be "data"
end;
TWaveHeader = record
ident1: array[0..3] of Char; // Must be "RIFF"
len: DWORD; // Remaining length after this header
ident2: array[0..3] of Char; // Must be "WAVE"
ident3: array[0..3] of Char; // Must be "fmt "
reserv: DWORD; // Reserved 4 bytes
wFormatTag: Word; // format type
nChannels: Word; // number of channels (i.e. mono, stereo, etc.)
nSamplesPerSec: DWORD; //sample rate
nAvgBytesPerSec: DWORD; //for buffer estimation
nBlockAlign: Word; //block size of data
wBitsPerSample: Word; //number of bits per sample of mono data
cbSize: Word; //the count in bytes of the size of
ident4: array[0..3] of Char; //Must be "data"
end;
With this structure you can get all the information's about a wave file you want to.
After this header following the wave data which contains the data for playing the wave file.
Now we trying to get the information's from a wave file. To be sure it's really a wave file, we test the information's:
function GetWaveHeader(FileName: TFilename): TWaveHeader;
const
riff = 'RIFF';
wave = 'WAVE';
var
f: TFileStream;
w: TWaveHeader;
begin
if not FileExists(Filename) then
exit; //exit the function if the file does not exists
try
f := TFileStream.create(Filename, fmOpenRead);
f.Read(w, Sizeof(w)); //Reading the file header
if w.ident1 <> riff then
begin //Test if it is a RIFF file, otherwise exit
Showmessage('This is not a RIFF File');
exit;
end;
if w.ident2 <> wave then
begin //Test if it is a wave file, otherwise exit
Showmessage('This is not a valid wave file');
exit;
end;
finally
f.free;
end;
Result := w;
end;
const
riff = 'RIFF';
wave = 'WAVE';
var
f: TFileStream;
w: TWaveHeader;
begin
if not FileExists(Filename) then
exit; //exit the function if the file does not exists
try
f := TFileStream.create(Filename, fmOpenRead);
f.Read(w, Sizeof(w)); //Reading the file header
if w.ident1 <> riff then
begin //Test if it is a RIFF file, otherwise exit
Showmessage('This is not a RIFF File');
exit;
end;
if w.ident2 <> wave then
begin //Test if it is a wave file, otherwise exit
Showmessage('This is not a valid wave file');
exit;
end;
finally
f.free;
end;
Result := w;
end;
Взято с Delphi Knowledge Base: http://www.baltsoft.com/
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