Re: [Sndobj-devel] SndLoop setting input and resampling

[Victor L. <Vic...@nu...>]

Sounds like a bug. I have never tried switching the input to it and 
then resampling. You
could try just running with some audio, without switching the output 
and then calling
resample() to see if it does what it supposed to do. I have used 
SndLoop like that quite
a lot and never encountered a problem.

When sampling, the input is connected directly to the output, ie:

         PutSample((m_output[m_vecpos] = m_input->Output(m_vecpos)));

PutSample() writes the signal into memory. So you are getting input OK.
Then when you are playing back it switches to this code:


                 m_output[m_vecpos] = GetSample();
             m_point += m_pitch;
             m_rpointer = (long)m_point;
             while(m_point >= m_size) m_point -= m_size;
                 while(m_point < 0) m_point += m_size;

Now the output is connected to memory only (through GetSample()). The
playback speed is controlled by m_pitch. If that is for some reason, set
to 0, you would be stuck in one memory location and would hear nothing
(possibly a click when switching off or on, but nothing else). Make sure
pitch is not 0.

Looking at the code, I can't see what else could be wrong. Calling SetInput()
only points the input object to a different object.

Victor

At 01:30 13/08/2009, Daniel Skinner wrote:
>Hi,
>
>Ive created a SndLoop object with a default input of sndobj.SndIn() 
>with a sample time of 2 seconds. As I understand, at this point is 
>should have sampled 2 seconds of nothing and be playing in a 
>continuous loop. Is that correct?
>
>Afterwards I play back a wav file with SndRead and sometime during 
>the playback i
>
>sndloop.SetInput(sndread)
>sndloop.ReSample()
>
>effectively. As it resamples for 2 seconds I can immediately see the 
>output of the sndloop as it plays back everything it is sampling and 
>then at 2 seconds it stops. No looping or anything. I could also set 
>the input to an oscili and it will produce the same effect. 2 
>seconds of pushing the same sound data to the output during 
>resampling, then silence afterwards, no looping. Im showing no 
>errors on the object and i can repeat the process as many times as i like.
>
>On a side note, its exciting to see with sndobj that i can start 
>sampling any portion of a signal chain that i may have going and 
>start messing with it. This is one of the first things i do when 
>creating ambient background noise for music i mix. Kudos
>
>Thanks,
>Daniel
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Victor Lazzarini
Music Technology Laboratory
Music Department
National University of Ireland, Maynooth