unit Unit1;

interface

uses
 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
 Dialogs, StdCtrls, MMSystem;

type
 TForm1 = class(TForm)
   Button1: TButton;
   ListBox1: TListBox;
   procedure Button1Click(Sender: TObject);
   procedure FormCreate(Sender: TObject);
 private
   { Private declarations }
 public
   { Public declarations }
 end;

var
 Form1: TForm1;

implementation

uses MSAcm;

var WaveFormatEx : PWaveFormatEx;
   ACMFmtDet : PACMFormatDetails;

{$R *.dfm}

function FormatEnumProc(hACMDrvId: HACMDRIVERID; const NewACMFmtDet: PAcmFormatDetails;
  dwInstance: DWord; fdwSupport: DWord): longbool; stdcall;
begin
  try Result := True;
      NewACMFmtDet^.pwfx^.cbSize:=0;  //÷òîáû íå ñðàâíèâàëî
      TListBox(dwInstance).Items.Add('F'+IntTostr(NewACMFmtDet^.pwfx^.wFormatTag)+
                    ' - C'+IntTostr(NewACMFmtDet^.pwfx^.nChannels)+
                    ' - SPS'+IntTostr(NewACMFmtDet^.pwfx^.nSamplesPerSec)+
                    ' - BPS'+IntTostr(NewACMFmtDet^.pwfx^.wBitsPerSample));
  except Result := False; end;
end;

function DriverEnumProc(hACMDrvId: HACMDRIVERID; dwInstance: DWord; fdwSupport: DWord): bool; stdcall;
var MaxSize: Word;
   hACMDrv: HACMDriver;
begin
 try
  Result := True;
  if (fdwSupport = ACMDRIVERDETAILS_SUPPORTF_CODEC) then
  begin
     FillChar(WaveFormatEx^, SizeOf(TWaveFormatEx), #0);
     FillChar(ACMFmtDet^, SizeOf(TACMFormatDetails), #0);
     hACMDrv := nil;
     if acmDriverOpen(hACMDrv, hACMDrvId, 0) = 0 then
     begin
        MaxSize := MAXWORD;
//acmMetrics(HACMOBJ(hACMDrv), ACM_METRIC_MAX_SIZE_FORMAT, MaxSize);
        if MaxSize < SizeOf(TWaveFormatEx) then MaxSize := SizeOf(TWaveFormatEx);
        WaveFormatEx^.cbSize := LoWord(MaxSize) - SizeOf(TWaveFormatEx);
        WaveFormatEx^.wFormatTag := 0;
        ACMFmtDet^.cbStruct := SizeOf(TACMFormatDetails);
        ACMFmtDet^.pwfx := WaveFormatEx;
        ACMFmtDet^.cbwfx := MaxSize;
        ACMFmtDet^.dwFormatTag := 0;
        acmFormatEnum(hACMDrv, ACMFmtDet^, @FormatEnumProc, dwInstance, 0);
        acmDriverClose(hACMDrv, 0);
     end
      else
         Result := False;
  end;
  except
     Result := False;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  Button1.Enabled:=false;
  acmDriverEnum(DriverEnumProc, integer(ListBox1), 0);
  Button1.Enabled:=true;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  New(WaveFormatEx);
  New(ACMFmtDet);
end;

end.

function DriverEnumProc(hACMDrvId: THandle;
  dwInstance: DWord; fdwSupport: DWord): bool; stdcall;
var MaxSize: Cardinal;
   hACMDrv: THandle;
   ACMFmtDet : PACMFormatDetails;
   ACMDrvDet : TACMDriverDetails;
   p:Pointer;
begin
  Result := True;
  if fdwSupport<>ACMDRIVERDETAILS_SUPPORTF_CODEC then Exit;
  ACMDrvDet.cbStruct := SizeOf(ACMDrvDet);
  hACMDrv := 0;
  try //if acmDriverDetails(hACMDrvId, ACMDrvDet, 0) = 0 then DriverName := ACMDrvDet.szLongName;
      if acmDriverOpen(hACMDrv, hACMDrvId, 0) = 0 then begin
        acmMetrics(HACMOBJ(hACMDrv), ACM_METRIC_MAX_SIZE_FORMAT, MaxSize);
        if MaxSize < SizeOf(TWaveFormatEx) then MaxSize := SizeOf(TWaveFormatEx);
        p:=AllocMem(MaxSize); FillChar(p^, MaxSize, 0);
        New(ACMFmtDet);       FillChar(ACMFmtDet^, SizeOf(TACMFormatDetails), 0);
        ACMFmtDet^.cbStruct := SizeOf(TACMFormatDetails);
        ACMFmtDet^.pwfx := p;
        ACMFmtDet^.cbwfx := MaxSize;
        ACMFmtDet^.dwFormatTag := 0;
        acmFormatEnum(hACMDrv, ACMFmtDet^, @FormatEnumProc, dwInstance, 0);
        acmDriverClose(hACMDrv, 0);
        Dispose(ACMFmtDet);
        FreeMem(p);
      end else Result := False;
  except Result := False; end;
end;