mmslow.pas

一套及时通讯的原码

{========================================================================}
{=                (c) 1995-98 SwiftSoft Ronald Dittrich                 =}
{========================================================================}
{=                          All Rights Reserved                         =}
{========================================================================}
{=  D 01099 Dresden             = Tel.: [phone]                   =}
{=  Loewenstr.7a                = [e-mail]                     =}
{========================================================================}
{=  Actual versions on http://www.swiftsoft.de/mmtools.html             =}
{========================================================================}
{=  This code is for reference purposes only and may not be copied or   =}
{=  distributed in any format electronic or otherwise except one copy   =}
{=  for backup purposes.                                                =}
{=                                                                      =}
{=  No Delphi Component Kit or Component individually or in a collection=}
{=  subclassed or otherwise from the code in this unit, or associated   =}
{=  .pas, .dfm, .dcu, .asm or .obj files may be sold or distributed     =}
{=  without express permission from SwiftSoft.                          =}
{=                                                                      =}
{=  For more licence informations please refer to the associated        =}
{=  HelpFile.                                                           =}
{========================================================================}
{=  $Date: 20.01.1998 - 18:00:00 $                                      =}
{========================================================================}
unit MMSLow;

{$I COMPILER.INC}

interface

uses
{$IFDEF WIN32}
    Windows,
{$ELSE}
    WinTypes,
    WinProcs,
{$ENDIF}
    SysUtils,
    Classes,
    Controls,
    MMSystem,
    MMRegs,
    MMObj,
    MMDSPObj,
    MMUtils,
    MMPCMSup,
    MMFX;

type
   EMMSimpleLowPassError = class(Exception);
   TMMFilterType = (ftNone,ftSoftLowPass,ftLowPass);

   {-- TMMSimpleLowPass -------------------------------------------------}
   TMMSimpleLowPass = class(TMMDSPComponent)
   private
      FEnabled   : Boolean;
      FOpen      : Boolean;
      FPFilter   : PSimpleFilter;
      FFilterType: TMMFilterType;

      procedure SetEnabled(aValue: Boolean);
      procedure SetFilterType(aValue: TMMFilterType);

   protected
      procedure SetPWaveFormat(aValue: PWaveFormatEx); override;
      procedure Update; virtual;
      procedure Opened; override;
      procedure Closed; override;
      procedure Started; override;
      procedure BufferReady(lpwh: PWaveHdr); override;
      procedure BufferLoad(lpwh: PWaveHdr; var MoreBuffers: Boolean); override;

   public
      constructor Create(aOwner: TComponent); override;
      destructor Destroy; override;

      procedure Open;
      procedure Close;
      procedure Process(Buffer: PChar; Length: integer);

   published
      property Input;
      property Output;
      property Enabled: Boolean read FEnabled write SetEnabled default True;
      property FilterType: TMMFilterType read FFilterType write SetFilterType default ftNone;
   end;

implementation

{== TMMSimpleLowPass ====================================================}
constructor TMMSimpleLowPass.Create(aOwner: TComponent);
begin
   inherited Create(aOwner);

   FEnabled    := True;
   FOpen       := False;
   FPFilter    := nil;
   FFilterType := ftNone;
end;

{-- TMMSimpleLowPass ----------------------------------------------------}
destructor TMMSimpleLowPass.Destroy;
begin
   Close;

   inherited Destroy;
end;

{-- TMMSimpleLowPass ----------------------------------------------------}
procedure TMMSimpleLowPass.SetEnabled(aValue: Boolean);
begin
   if (aValue <> FEnabled) then
   begin
      FEnabled := aValue;
      if FEnabled then Update;
   end;
end;

{-- TMMSimpleLowPass ----------------------------------------------------}
procedure TMMSimpleLowPass.SetFilterType(aValue: TMMFilterType);
begin
   if (aValue <> FFilterType) then
   begin
      FFilterType := aValue;
      Update;
   end;
end;

{-- TMMSimpleLowPass ----------------------------------------------------}
procedure TMMSimpleLowPass.SetPWaveFormat(aValue: PWaveFormatEx);
begin
   if (aValue <> nil) then
   begin
      if not (csDesigning in ComponentState) then
         if not pcmIsValidFormat(aValue) then
            raise EMMSimpleLowPassError.Create(LoadResStr(IDS_INVALIDFORMAT));
   end;
   inherited SetPWaveFormat(aValue);
end;

{-- TMMSimpleLowPass ----------------------------------------------------}
procedure TMMSimpleLowPass.Open;
begin
   if not FOpen then
   begin
      if pcmIsValidFormat(PWaveFormat) then
      begin
         FPFilter := InitSimpleLowPass(PWaveFormat);
         if (FPFilter = nil) then OutOfMemoryError
         else
         begin
            FOpen := True;
            Update;
         end;
      end;
   end;
end;

{-- TMMSimpleLowPass ----------------------------------------------------}
procedure TMMSimpleLowPass.Close;
begin
   if FOpen then
   begin
      FOpen := False;
      DoneSimpleLowPass(FPFilter);
   end;
end;

{-- TMMSimpleLowPass ----------------------------------------------------}
procedure TMMSimpleLowPass.Process(Buffer: PChar; Length: integer);
begin
   { process the buffer trough the filter }
   if (FPFilter <> nil) then DoSimpleLowPass(FPFilter, Buffer, Length);
end;

{-- TMMSimpleLowPass ----------------------------------------------------}
procedure TMMSimpleLowPass.Update;
begin
   { setup the filter with the params }
   if FOpen then
   begin
      SetSimpleLowPass(FPFilter, Ord(FFilterType));
   end;
end;

{-- TMMSimpleLowPass ----------------------------------------------------}
procedure TMMSimpleLowPass.Opened;
begin
   Open;

   inherited Opened;
end;

{-- TMMSimpleLowPass ----------------------------------------------------}
procedure TMMSimpleLowPass.Closed;
begin
   Close;

   inherited Closed;
end;

{-- TMMSimpleLowPass ----------------------------------------------------}
procedure TMMSimpleLowPass.Started;
begin
   Update;

   inherited Started;
end;

{-- TMMSimpleLowPass ----------------------------------------------------}
procedure TMMSimpleLowPass.BufferReady(lpwh: PWaveHdr);
begin
   if Enabled and FOpen then
   begin
      Process(lpwh^.lpData, lpwh^.dwBytesRecorded);
   end;

   inherited BufferReady(lpwh);
end;

{-- TMMSimpleLowPass ----------------------------------------------------}
procedure TMMSimpleLowPass.BufferLoad(lpwh: PWaveHdr; var MoreBuffers: Boolean);
begin
   inherited BufferLoad(lpwh, MoreBuffers);

   if Enabled and FOpen then
   begin
      Process(lpwh^.lpData, lpwh^.dwBytesRecorded);
   end;
end;

end.