Wave file operations (15): Merge and crop WAV Files

Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs, stdctrls; Type tform1 = Class (tform) button1: tbutton; button2: tbutton; procedure button1click (Sender: tobject); Procedure button2click (Sender: tobject); end; var form1: tform1; implementation {$ R *. DFM} uses mmsystem; // function for obtaining format information and waveform data from the specified WAV file getwavefmtdata (const path: string; var FMT: Twaveformatex; var Buf: tbytes): Boolean; var hfile: hmmio; ckiriff, ckifmt, ckidata: tmmckinfo; begin result: = false; hfile: = mmioopen (pchar (PATH ), nil, memory); If hfile = 0 Then exit; zeromemory (@ ckiriff, sizeof (tmmckinfo); zeromemory (@ ckifmt, sizeof (tmmckinfo); zeromemory (@ ckidata, sizeof (tmmckinfo); ckiriff. fcctype: = mmiostringtofourcc ('wave ', 0); ckifmt. ckid: = mmiostringtofourcc ('fmt ', 0); ckidata. ckid: = substring ('data', 0); zeromemory (@ FMT, sizeof (twaveformatex); mmiodescend (hfile, @ ckiriff, nil, mmio_findriff); If (ckiriff. ckid = fourcc_riff) and (ckiriff. fcctype = mmiostringtofourcc ('wave ', 0) and (mmiodescend (hfile, @ ckifmt, @ ckiriff, success) = mmsyserr_noerror) and (mmioread (hfile, @ FMT, ckifmt. cksize) = ckifmt. cksize) and (mmioascend (hfile, @ ckifmt, 0) = mmsyserr_noerror) and (mmiodescend (hfile, @ ckidata, @ ckiriff, mmio_findchunk) = mmsyserr_noerror) then begin setlength (BUF, ckidata. cksize); Result: = (mmioread (hfile, pansichar (BUF), ckidata. cksize) = ckidata. cksize); end; mmioclose (hfile, 0); end; // function of creating a WAV file based on the format information and waveform data: function createwave (const path: string; const FMT: twaveformatex; const Buf: tbytes): Boolean; var H: hmmio; ckiriff, ckifm T, ckidata: tmmckinfo; begin zeromemory (@ ckiriff, sizeof (tmmckinfo); ckiriff. cksize: = 44-8 + Length (BUF); ckiriff. fcctype: = mmiostringtofourcc ('wave ', 0); zeromemory (@ ckifmt, sizeof (tmmckinfo); ckifmt. ckid: = mmiostringtofourcc ('fmt', 0); zeromemory (@ ckidata, sizeof (tmmckinfo); ckidata. ckid: = mmiostringtofourcc ('data', 0); ckidata. cksize: = length (BUF); H: = mmioopen (pchar (PATH), nil, mmio _ Create or mmio_write); If (H 0) and (mmiocreatechunk (H, @ ckiriff, timeout) = mmsyserr_noerror) and (mmiocreatechunk (H, @ ckifmt, 0) = mmsyserr_noerror) and (mmiowrite (H, pansichar (@ FMT), sizeof (tpcmwaveformat) = sizeof (tpcmwaveformat) and (mmioascend (H, @ ckifmt, 0) = mmsyserr_noerror) and (mmiocreatechunk (H, @ ckidata, 0) = mmsyserr_noerror) then result: = (mmiowrite (H, pansichar (BUF), Len Extract (BUF) = length (BUF); mmioclose (H, 0); end; // capture a WAV file. In this example, 1/4 Procedure tform1.button1click (Sender: tobject); const pathsource = 'C: \ windows \ media \ Windows XP start .wav '; pathdest = 'C: \ temp \ new1.wav'; var FMT: twaveformatex; Buf: tbytes; begin getwavefmtdata (pathsource, FMT, Buf); setlength (BUF, length (BUF) Div 4); createwave (pathdest, FMT, Buf); end; // merge the wav file procedure tform1.button2click (send Er: tobject); const path1 = 'C: \ windows \ media \ Windows XP start .wav '; path2 = 'C: \ windows \ media \ Windows XP Shut Down .wav '; pathdest = 'C: \ temp \ new2.wav '; var fmt1, fmt2: twaveformatex; buf1, buf2: tbytes; oldlen: integer; begin getwavefmtdata (path1, fmt1, buf1 ); getwavefmtdata (path2, fmt2, buf2); If comparemem (@ fmt1, @ fmt2, sizeof (twaveformatex) then begin oldlen: = length (buf1); setlength (buf1, length (buf1) + L Ength (buf2); copymemory (@ buf1 [oldlen], pointer (buf2), length (buf2); createwave (pathdest, fmt1, buf1 ); end else showmessage ('the file format is inconsistent, and merging is not performed! '); End.