Perfect looping possible?

[Cluq]

Hi

I'm using the AudioPlayer to play a looping wave file. The looping works, but not perfectly. There is a very small silence before the wave starts over again and I would like it to loop without that silence. I have checked the wave file - it loops perfectly in SoundForge.

This is the simple code I've been using:

-----------------
type
TForm1 = class(TForm)
CheckBox1: TCheckBox;
AudioPlayer1: TAudioPlayer;
procedure AudioPlayer1Deactivate(Sender: TObject);
procedure CheckBox1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.AudioPlayer1Deactivate(Sender: TObject);
begin
AudioPlayer1.Active := checkbox1.Checked;
end;

procedure TForm1.CheckBox1Click(Sender: TObject);
begin
AudioPlayer1.Active := checkbox1.Checked;
end;
------------

Have any of you a better idea to get perfect looping?

Best regards,
Cluq.

[Kambiz]

Hi,

You can use LiveAudioPlayer. In the event hanlder for supplying the wave data, you can specify the number of loops.

Cheers,
Kambiz

[Cluq]

Ok, thank you very much.

I've been looking at the LiveAudioPlayer Demo (the receiver part). I get the part that the variable WaveFormat is where the actual wave data is loaded into, right? But how would you go about loading wave data from a local wave-file on your harddrive?

/Cluq

[Kambiz]

Use a TWaveStorage instance.

Code: Select all

procedure TForm1.LiveAudioPlayer1Format(Sender: TObject;
  out pWaveFormat: PWaveFormatEx; var FreeIt: Boolean);
begin
  FreeIt := False;
  pWaveFormat := WaveStorage1.Wave.WaveFormat;
end;

function TForm1.LiveAudioPlayer1DataPtr(Sender: TObject;
  out Buffer: Pointer; var NumLoops: Cardinal;
  var FreeIt: Boolean): Cardinal;
begin
  FreeIt := False;
  NumLoops := $FFFFFFFF; // infinite
  Buffer := WaveStorage1.Wave.Data;
  Result := WaveStorage1.Wave.DataSize;
end;

By the way, set LiveAudioPlayer.BufferCount to 1 and LiveAudioPlayer.BufferInternally to False.

[Cluq]

Ahh...of course...I'll be trying that out...

Btw, if I get positive results from this, I will most likely use this in my freeware game I'm writing... It is almost done, except for the sound. I have been using another unit for playing sound, but it had memory leaks and other crappy things wrong with it, so I'm looking for a better unit.

But this is looking quite nice so far...

/Cluq

[Cluq]

I have now done exactly as you said, but the sound doesn't loop. It only play once... LiveAudioPlayer.Active remains true - there is just silence...

The audio file is PCM 44,100 kHz, 16bit, Stereo...

[Cluq]

Have I found a bug?

[Kambiz]

Yes, there's a bug. Open the WaveOut.pas file and look for

Code: Select all

WHDR_BEGINLOOP or WHDR_BEGINLOOP

then replace it with

Code: Select all

WHDR_BEGINLOOP or WHDR_ENDLOOP

By the way, you can leave the NumLoops as zero. Because when a buffer finished, the OnDataPtr event will be raised once more, until your return zero as result. If you set the NumLoops parameter, in the next call of the event you should return zero. So, my prevoius code is wrong.

Solution 1:

Code: Select all

LiveAudioPlayer1.BufferInternally := False;

procedure TForm1.LiveAudioPlayer1Format(Sender: TObject;
  out pWaveFormat: PWaveFormatEx; var FreeIt: Boolean);
begin
  FreeIt := False;
  pWaveFormat := WaveStorage1.Wave.WaveFormat;
end;

function TForm1.LiveAudioPlayer1DataPtr(Sender: TObject;
  out Buffer: Pointer; var NumLoops: Cardinal;
  var FreeIt: Boolean): Cardinal;
begin
  FreeIt := False;
  Buffer := WaveStorage1.Wave.Data;
  Result := WaveStorage1.Wave.DataSize;
end;

Solution 2:

Code: Select all

var
  AlreadyFed: Boolean = False;

LiveAudioPlayer1.BufferInternally := False;

procedure TForm1.LiveAudioPlayer1Format(Sender: TObject;
  out pWaveFormat: PWaveFormatEx; var FreeIt: Boolean);
begin
  FreeIt := False;
  pWaveFormat := WaveStorage1.Wave.WaveFormat;
end;

function TForm1.LiveAudioPlayer1DataPtr(Sender: TObject;
  out Buffer: Pointer; var NumLoops: Cardinal;
  var FreeIt: Boolean): Cardinal;
begin
  if not AlreadyFed then
  begin
    FreeIt := False;
    NumLoops := $FFFFFFF; // Infinite
    Buffer := WaveStorage1.Wave.Data;
    Result := WaveStorage1.Wave.DataSize;
    AlreadyFed := True;
  end
  else
    Result := 0;
end;

I'm sorry for being so late.

[cozturk]

when I load a stream from a file the loop is excellent.
unfortunately my stream is not static. For example
Buffer := filebuf4.Memory;
Result := filebuf4.Size;
NumLoops := $FFFFFFF; // Infinite
yes it plays continuous. But I need to clear the stream and load new data. To playing live audio stream which comes from a hardware

But it can not be done this when player loops .

If It plays the stream for once only, how can I load new data ? LiveAudioPlayer disable, and load new data and Enable again? It can be interrupted.

Is it possible to modify TAudioRedirector to fed with my stream?

[Kambiz]

cozturk,

There was a missing method in TLiveAudioPlayer for breaking the loop. I added it (BreakLoop), and you can download the update from the site.

After calling the BreakLoop method, the player continues with the next buffer if any.

Here is a sample (suppose all waves are same format):

Code: Select all

object Form1: TForm1
  Left = 192
  Top = 114
  Width = 696
  Height = 480
  Caption = 'Form1'
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'MS Sans Serif'
  Font.Style = []
  OldCreateOrder = False
  PixelsPerInch = 96
  TextHeight = 13
  object CheckBox1: TCheckBox
    Left = 96
    Top = 24
    Width = 97
    Height = 17
    Caption = 'Active'
    TabOrder = 0
    OnClick = CheckBox1Click
  end
  object Button1: TButton
    Left = 208
    Top = 24
    Width = 75
    Height = 25
    Caption = 'Break Loop'
    TabOrder = 1
    OnClick = Button1Click
  end
  object LiveAudioPlayer1: TLiveAudioPlayer
    PCMFormat = Stereo16bit22050Hz
    BufferInternally = False
    OnActivate = LiveAudioPlayer1Activate
    OnDeactivate = LiveAudioPlayer1Deactivate
    OnDataPtr = LiveAudioPlayer1DataPtr
    Left = 40
    Top = 64
  end
  object WaveCollection1: TWaveCollection
    Waves = <
      item
        Name = 'chimes'
        Data = {
                // Data is removed to simplify the view...
        }
      end
      item
        Name = 'ding'
        Data = {
                // Data is removed to simplify the view...
        }
      end>
    Left = 40
    Top = 16
  end
end


Code: Select all

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, mmSystem, WaveUtils, WaveIO, WaveOut, WavePlayers, WaveStorage,
  StdCtrls;

type
  TForm1 = class(TForm)
    LiveAudioPlayer1: TLiveAudioPlayer;
    CheckBox1: TCheckBox;
    WaveCollection1: TWaveCollection;
    Button1: TButton;
    function LiveAudioPlayer1DataPtr(Sender: TObject; out Buffer: Pointer;
      var NumLoops: Cardinal; var FreeIt: Boolean): Cardinal;
    procedure CheckBox1Click(Sender: TObject);
    procedure LiveAudioPlayer1Activate(Sender: TObject);
    procedure LiveAudioPlayer1Deactivate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

function TForm1.LiveAudioPlayer1DataPtr(Sender: TObject;
  out Buffer: Pointer; var NumLoops: Cardinal;
  var FreeIt: Boolean): Cardinal;
begin
  FreeIt := False;
  if (Tag >= 0) and (Tag < WaveCollection1.Waves.Count) then
  begin
    Buffer := WaveCollection1.Waves[Tag].Wave.Data;
    Result := WaveCollection1.Waves[Tag].Wave.DataSize;
    NumLoops := $FFFFFFFF;
    Tag := Tag + 1;
  end
  else
  begin
    Buffer := nil;
    Result := 0;
  end;
end;

procedure TForm1.CheckBox1Click(Sender: TObject);
begin
  LiveAudioPlayer1.Active := CheckBox1.Checked;
end;

procedure TForm1.LiveAudioPlayer1Activate(Sender: TObject);
begin
  Tag := 0;
  CheckBox1.Checked := True;
end;

procedure TForm1.LiveAudioPlayer1Deactivate(Sender: TObject);
begin
  CheckBox1.Checked := False;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  LiveAudioPlayer1.BreakLoop;
end;

end.

Cheers

[cozturk]

thanks. I tested your demo and understood that:
We must load the next buffer before calling the BreakLoop method.
Here is example(mentioned above) to easy testing or modifiying for other members:
http://s6.ultrashare.net/hosting/fs/94708f65b808b2c9/

I wish www.delphiarea.com have Project(or examples) Sharing Area

[Pherreira]

Hello,
I was testing the function and the delphi is complaining over this line, the property Data doesn't exist .
Can you please help me?
I am using Delphi XE2 with Windows 7

Code: Select all

function TForm1.LiveAudioPlayer1DataPtr(Sender: TObject;
  out Buffer: Pointer; var NumLoops: Cardinal;
  var FreeIt: Boolean): Cardinal;
begin
  FreeIt := False;
  if (Tag >= 0) and (Tag < WaveCollection1.Waves.Count) then
  begin
    Buffer := WaveCollection1.Waves[Tag].Wave.Data; // <- here is the error
    Result := WaveCollection1.Waves[Tag].Wave.DataSize;
    NumLoops := $FFFFFFFF;
    Tag := Tag + 1;
  end
  else
  begin
    Buffer := nil;
    Result := 0;
  end;
end;

[Kambiz]

Hello Pherreira,

I'm sorry but currently my computer is broken and I can check the code. However, as I remember the WaveAudio package has no issue with Delphi XE3.