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[Reilloch]

Hello there, 
Using Delphi XE2 (Pascal) I have written a  FFT function however i need to be able to pass it data from a microphone signal. So far i have been unable to work out how to use bass to pass the function the next N values for use in the FFT. Is there a simple function/way to do this which i have overlooked or is it more complex than i first thought?

Thanks in advance

[Ian @ un4seen]

If you would like to receive/process the recorded data in fixed size blocks, you can do so by not using a RECORDPROC callback function, ie. passing NULL to BASS_RecordStart. You can then use BASS_ChannelGetData to get the amount of data that you want. Something like this...

recording=BASS_RecordStart(freq, chans, 0, NULL, NULL); // start recording without a RECORDPROC

...

DWORD avail=BASS_ChannelGetData(recording, NULL, BASS_DATA_AVAILABLE); // get amount of data in the recording buffer
if (avail>=wanted) { // the wanted amount is available
BASS_ChannelGetData(recording, buffer, wanted); // get the wanted amount of data
// process the data...
}

[Reilloch]

If you would like to receive/process the recorded data in fixed size blocks, you can do so by not using a RECORDPROC callback function, ie. passing NULL to BASS_RecordStart. You can then use BASS_ChannelGetData to get the amount of data that you want. Something like this...

recording=BASS_RecordStart(freq, chans, 0, NULL, NULL); // start recording without a RECORDPROC

...

DWORD avail=BASS_ChannelGetData(recording, NULL, BASS_DATA_AVAILABLE); // get amount of data in the recording buffer
if (avail>=wanted) { // the wanted amount is available
BASS_ChannelGetData(recording, buffer, wanted); // get the wanted amount of data
// process the data...
}

Thank you very much, i shall try this later today

[Reilloch]

<code>

Function Tform2.Rec;
var
avail:Dword;
begin
repeat
Recording:=Bass_RecordStart(44100,2,0,@NULL,@NULL);//Start recording without Record Proc;
avail:=Bass_ChannelGetData(recording,@Buffer,BASS_DATA_AVAILABLE); // retrieve the ammount of data in the buffer
{if avail>=NB then
BASS_ChannelGetData(Recording,@Buffer,NB);}
until avail>=NB;
BASS_ChannelGetData(Recording,@Buffer,NB);
end;
</Code>

That is the code i have written
with buffer declared in a type like so :
<code>
Buf3 = array [0..NB-1] of extended;
var
Buffer:Buf3;
</code>

This code works however i can't seem to get values other than 0 in the buffer.
Do i need to specify my recording device?
Any suggestions?

Thanks 

[Chris]

Function Tform2.Rec;
var
avail:Dword;
begin
repeat
Recording:=Bass_RecordStart(44100,2,0,@NULL,@NULL);//Start recording without Record Proc;
avail:=Bass_ChannelGetData(recording,@Buffer,BASS_DATA_AVAILABLE); // retrieve the ammount of data in the buffer
{if avail>=NB then
BASS_ChannelGetData(Recording,@Buffer,NB);}
until avail>=NB;
BASS_ChannelGetData(Recording,@Buffer,NB);
end;

bass-recordstart in a while/repeat call makes no sense
should be

Function Tform2.Rec;
var
  avail:Dword;
begin
   Recording:=Bass_RecordStart(44100,2,0,nil,nil);//Start recording without Record Proc;
   while Bass_ChannelIscative(recording)> 0 do
      begin
         avail:=Bass_ChannelGetData(recording,nil,BASS_DATA_AVAILABLE); // retrieve the ammount of data in the buffer
         if avail>=NB then
           BASS_ChannelGetData(Recording,@Buffer,NB);}
      end;
     end;
 end;

[Reilloch]

I have changed it however buffer is still returning 0 to me. Do i need to specify and initialise my recording device? if so how do i do this?

[Chris]

Place after

Recording:=Bass_RecordStart(44100,2,0,nil,nil);//Start recording without Record Proc;

a Bass_ErrorGetCode call to see whats going wrong
Chris

[Reilloch]

Place after

Recording:=Bass_RecordStart(44100,2,0,nil,nil);//Start recording without Record Proc;

a Bass_ErrorGetCode call to see whats going wrong
Chris

I recieve 8   BASS_ERROR_INIT  - any suggestions?

[Chris]

you have to add

procedure TForm2.OnCreate(Sender:TObject);
begin
   Bass_Init(-1, 44100, 0, handle, nil);//-1 the default SoundDevice
end;

procedure TForm2.OnDestroy(Sender:TObject);
begin
   Bass_Free();
end;

[Reilloch]

thank you for your last response

The program now works, However After running the program for a while Bass error code 5 pops up. Not quite sure why - this seems to happen after about 50 loops of my main program. Any suggestions as i would like to be able to loop this indefinatley..

[Chris]

Change it to

Function Tform2.Rec;
var
  avail:Dword;
begin
   Recording:=Bass_RecordStart(44100,2,0,nil,nil);//Start recording without Record Proc;
   while Bass_ChannelIscative(recording)> 0 do
      begin
         avail:=Bass_ChannelGetData(recording,nil,BASS_DATA_AVAILABLE); // retrieve the ammount of data in the buffer
         if avail>=NB then
           BASS_ChannelGetData(Recording,@Buffer,sizeof(Buffer);
      end;
     end;
 end;

[Reilloch]

This all now works perfectly. One last question, is there a way for me to vary the volume of the microphone recording (like using the windows slider under sound in control panel)?

Thanks