How to normalize audio input?

Hello, does anybody know how wavrecord function scales PCM format (range 0-256 or 0-65536) into -1;1 interval? many thanks for answers

Answer 1

[Daniel Shub]

The wavrecord function does not do the scaling but rather the recsnd function handles the scaling. The recsnd function is/was not a well defined entity since it was a platform dependent mex file and in some cases it used audiorecorder. The wavrecord function is now obsolete and is slated to be removed, so there is no single version...

That said, (x-128)/128 is probably a reasonable approximation of the conversion. Do you have reason to doubt this?

Answer 2

[fei]

Thank you for your answer Daniel, finally I used mapminmax function which uses this algorithm: y = (ymax-ymin)*(x-xmin)/(xmax-xmin) + ymin;

[Jan]

Please post comments in the comment section of the corresponding answer, not as further answer. Thanks.

Answer 3

[Antonio Ferreras]

The problem con mapminmax is that it introduces a continuus bias