streaming sound in realtime

I want to stream sound from the microphone,perform some processing on it(though i have done nothing in this code here) and play it back.The lower the phase lag the better it serves me(less than a millisecond(For when i'm using 1000 HZ audio)is needed).(Initial phase i haven't taken care of that much though it can be reduced)To achieve that i tried the following code, but if you run it u may see that the phase lag is increasing as time goes on!!! and that should be also because of 600 additional data in 13 line is introduced! But if i don't do that the buffer runs out of data. So what do you suggest?

clc

clear all

close all

ao = analogoutput('winsound');
addchannel(ao,1:2);

data=wavrecord(11025,11025,1);

set(ao,'SampleRate',11025);

set(ao,'SamplesOutputFcnCount',1);

putdata(ao,[data data]);

start(ao)

for i=1:100000

    clear data

    data=wavrecord(5512,11025,1);

    data=[data;data(4912:5512)];

    putdata(ao,[data data])

end

Answer 1

[Daniel Shub]

You will probably have better control if you use the DAQ toolbox for everything (i.e create an analogoutput and an analogutinput object) instead of mixing it with wavrecord. That said, if you want reasonable good sound streaming you have to switch to port audio.

Answer 2

[Walter Roberson]

Please see this previous discussion

Short answer: 1 ms is not feasible with that configuration.

[Partha Ghosh]

ok if 1ms is too short for matlab, lets forget about the phase shift. CAN YOU MAKE SOMETHING WICH WILL STREAM AUDIO SMOOTHLY? i mean some way in which i neednt do the following silly thing!!

data=[data;data(4912:5512)];

about 400 false data eachtime!!

thanks