LZScene

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//
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// This unit is part of the GLScene Engine https://github.com/glscene
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//
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{
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   Support for MP3 format.
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	 History :  
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       25/07/09 - DaStr - Added $I GLScene.inc  
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       06/05/09 - DanB - Creation from split from GLSoundFileObjects.pas
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}
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unit GLFileMP3;
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interface
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{$I GLScene.inc}
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uses
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  Classes, GLApplicationFileIO, GLSoundFileObjects;
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type
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   // TGLMP3File
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   //
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   { Support for MP3 format.
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      *Partial* support only, access to PCMData is NOT supported. }
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   TGLMP3File = class (TGLSoundFile)
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      private
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         data : array of Byte; // used to store MP3 bitstream
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      protected
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      public
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         function CreateCopy(AOwner: TPersistent) : TGLDataFile; override;
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         class function Capabilities : TGLDataFileCapabilities; override;
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         procedure LoadFromStream(Stream: TStream); override;
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         procedure SaveToStream(Stream: TStream); override;
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         procedure PlayOnWaveOut; override;
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	      function WAVData : Pointer; override;
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         function WAVDataSize : Integer; override;
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	      function PCMData : Pointer; override;
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	      function LengthInBytes : Integer; override;
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   end;
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implementation
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// ------------------
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// ------------------ TGLMP3File ------------------
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// ------------------
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// CreateCopy
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//
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function TGLMP3File.CreateCopy(AOwner: TPersistent) : TGLDataFile;
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begin
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   Result:=inherited CreateCopy(AOwner);
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   if Assigned(Result) then begin
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      TGLMP3File(Result).data := Copy(data);
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   end;
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end;
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// Capabilities
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//
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class function TGLMP3File.Capabilities : TGLDataFileCapabilities;
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begin
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   Result:=[dfcRead, dfcWrite];
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end;
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// LoadFromStream
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//
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procedure TGLMP3File.LoadFromStream(stream : TStream);
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begin
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   // MP3 isn't actually, just loaded directly...
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   Assert(Assigned(stream));
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   SetLength(data, stream.Size);
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   if Length(data)>0 then
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      stream.Read(data[0], Length(data));
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end;
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// SaveToStream
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//
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procedure TGLMP3File.SaveToStream(stream: TStream);
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begin
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   if Length(data)>0 then
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      stream.Write(data[0], Length(data));
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end;
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// PlayOnWaveOut
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//
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procedure TGLMP3File.PlayOnWaveOut;
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begin
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   Assert(False, 'MP3 playback on WaveOut not supported.');
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end;
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// WAVData
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//
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function TGLMP3File.WAVData : Pointer;
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begin
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   if Length(data)>0 then
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      Result:=@data[0]
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   else Result:=nil;
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end;
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// WAVDataSize
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//
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function TGLMP3File.WAVDataSize : Integer;
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begin
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   Result:=Length(data);
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end;
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// PCMData
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//
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function TGLMP3File.PCMData : Pointer;
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begin
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   Result:=nil;
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end;
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// LengthInBytes
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//
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function TGLMP3File.LengthInBytes : Integer;
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begin
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   Result:=0;
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end;
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initialization
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  RegisterSoundFileFormat('mp3', 'MPEG Layer3 files', TGLMP3File);
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end.
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