ACS_Classes

procedure GetData( var Buffer :  Pointer; var Bytes :  LongWord ); virtual

This method retrieves input data.  You specify the number of bytes you want to get, but you may get less and it should not be considered as an end of input indication.  When the end of input is reached GetData sets Buffer to nil and Bytes to 0.

Parameters

Note

Usually you should not call this method directly.

function CopyData( Buffer :  Pointer; BufferSize :  Integer ) : LongWord

Writes no more than BufferSize data into Buffer

Parameters

function FillBuffer( Buffer :  Pointer; BufferSize :  LongWord; var EOF :  Boolean ) : LongWord

The same as CopyData but tries to fill the Buffer.  EOF is set to True if end of data was reached while filling the buffer, the buffer itself may still contain valid data.

Parameters

Returns

procedure Init

This method prepares input component for reading data.  Usually this method is called internally by the output or converter component to which the input component is assigned.  You can call this method if you want to get direct access to the audio stream.  In such a case the sequence of calls should look like this.

InputComponent.Init;
InputComponent.GetData(...); // in a loop
InputComponent.Flush;

procedure Flush

This method closes the current input (opened with Init), clearing up all temporary structures allocated during data transfer.  Usually this method is called internally by the output or converter component to which the input component is assigned.  You can call this method if you want to get direct access to the audio stream.  In such a case the sequence of calls should look like this.

InputComponent.Init;
InputComponent.GetData(...); // in a loop
InputComponent.Flush;

procedure Pause

Pauses the output.

procedure Resume

Resumes previously paused output.

procedure Run

After an input component has been assigned, call Run to start the audio processing chain.  When called, Run returns at once while the actual audio processing goes on in the different thread.  You will get OnProgress events while audio processing continues and an OnDone event when the job is done.

procedure BlockingRun

In some situations, such as console programs or DUnit test units, background processing is not desirable.  In these cases, call BlockingRun to run the output component and wait until all operations are complete before returning from the method.  It is only fair to note that since there is no way to abort, pause, or stop the procedure once it has started, if used improperly this method can lock your program.  If you are unsure which method to use, use the Run method.  Under normal circumstances, call Run to allow audio processing to go on in the background while your application is free to respond to events.

procedure Stop( Async :  Boolean  =  True )

Stops the busy component or does nothing if the component is idle.

Parameters

function SeekInternal( var SampleNum :  Int64 ) : Boolean; virtual; abstract

This abstract method should be overridden with an implementation dependong on whether your input component is seekable or not.  If your component is not seekable then you can write a method like the following.

function TMyComponent.SeekInternal(var SampleNum : Int64) : Boolean;
begin
  Result := False;
end;

If you want to make your component seekable you have to implement real seeking in this function.

function Seek( SampleNum :  Int64 ) : Boolean

This method allows you to change the current playing position in the the input component.  If the input component is stopped or paused, calling Seek sets the sample from which the playback will begin.  Note that not all inputs are seekable.

Parameters

Returns

procedure OpenFile; virtual; abstract

Opens the file or stream if it is not already open.  For performance reasons the file is opened when any of its data is accessed the first time and is then kept open until it is done with.  The descendants’ FileOpen implementations use the FOpened constant to check if the file is already opened.

Note

This method is called internally by TAuInput.Init, you should never call it directly.

procedure CloseFile; virtual; abstract

Closes the file opened with OpenFile.  Sets the FOpened constant to 0.

Note

This method is called internally by TAuInput.Flush, you should never call it directly.

function SetStartTime( Minutes,   Seconds :  LongWord ) : Boolean

This function is a wrapper around StartSample property, provided for convenience.  It allows you to set playback start position in minutes and seconds.

Parameters

Note

SetStartTime(1, 30);

and

SetStartTime(0, 90);

are both allowed.

function SetEndTime( Minutes,   Seconds :  LongWord ) : Boolean

This function is a wrapper around EndSample property, provided for convenience.  It allows you to set playback stop position in minutes and seconds.

Parameters

This method, being a wrapper around <Seek>, simpifies navigation in the input stream.  Calling Jump moves you backward or forward relative to the current position.  Jump may be called either before starting playback (in this case the playback will be started from the position specified) or during the playback.

Parameters

For example calling Jump(-100) always sets the playing position at the beginning of the file.

Note

Use <Seek> for more exact positioning.

procedure StartRecord

Call this method to start recording audio data passing through an audio tap.

procedure StopRecord

Call this method to stop recording.

procedure PauseRecord

Call this method to pause recording.

procedure ResumeRecord

Call this method to resume paused recording.