[Jack-Devel] Introducing delay into simple_client.c

Hi everyone,

I'm brand new to JACK and its implementation, so please bear with me.
I'm looking to modify the example script simple_client.c to introduce
a predetermined time delay from the input to the output.  I.e.,
unmodified, simple_client.c simply copies the input to the output, and
instead, I would like to take the input, delay it by t seconds, and
then send it to the output.

To do this, I thought I would declare an array of type
jack_default_audio_sample_t and then store the input into that array
until the critical time where it should start playing it to the
output. The new input then overwrites the old input by cycling through
the array from the beginning.

Here's my process callback (with comments on my reasoning):

//Initialize counting integers
int i = 0;
int j = 0;

//Initialize storage array
jack_default_audio_sample_t *prev[200]; //Note: 200 is just a test number

int process (jack_nframes_t nframes, void *arg)
{
   //For the first 200 cycles, store input into array, don't output anything
    if (i<200){

        prev[i] = (jack_default_audio_sample_t *) jack_port_get_buffer
(input_port, nframes);
        i++;
    }

    //For all following cycles, play the input, starting from the
beginning of the array
    else {

    jack_default_audio_sample_t *out = (jack_default_audio_sample_t *)
jack_port_get_buffer (output_port, nframes);
    memcpy (out, prev[j], sizeof (jack_default_audio_sample_t) *
nframes); //Note: j is the new counting variable

   //Overwrite recently played input with new input:
    prev[j] = (jack_default_audio_sample_t *) jack_port_get_buffer
(input_port, nframes);
    j++;

   //Reset array counter to 0 when it reaches the end
    if (j = 200){ j = 0; } //reset j
    }

return 0;
}

If this looks way off (as in I'm missing the point of how JACK, etc.
works), I'd appreciate any resources that might help me get started
with regards to understanding how this all works.  I have gone through
the tutorials listed on the JACK site, and have a lot of troubles
trying to find anything else.

Regards,
Jason

1351580380.29863_0.ltw:2,a <CAMMKq3RLON1LkUgpLzjvRhT+f9eDN2NY=wOcDvC1eZQA5_bC8g at mail dot gmail dot com>