Nyquist prompt/audio export

[stratblue]

Hi there.

I found this post:

Regular Interval Labels - By Sample Length?

Audacity tends to slow down quite badly if there are a vast number of labels, so you will probably need to work in sections rather than all in one go. I’d guess that you should be OK with with 1000 labels, so this code sets a limit of 1000 labels (line 3). This code can be run in the Nyquist prompt. I think it is fairly self explanatory, but feel free to ask questions: (setq num-samples 98304) (setq step (/ num-samples *sound-srate*)) (setq max-labels 1000) (setf labels ()) ; initialise an em…

which did exactly what I needed so thanks for that, Steve, much appreciated. However being a programming know nothing I have no idea how to change it to do what I need now which is very similar but I just need to extend the length of the exported audio. Say my number of samples was 1000, that’s where the label markers go but I want the audio exports to be 1200 samples long meaning that 200 samples of audio would be exported twice, the last 200 of audio export A would also be the first 200 of audio export B. ‘Paging Steve, Steve to the courtesy phone please, thank you.’

[steve]

@stratblue

Say my number of samples was 1000, that’s where the label markers go but I want the audio exports to be 1200 samples long meaning that 200 samples of audio would be exported twice, the last 200 of audio export A would also be the first 200 of audio export B.

To get an overlap like this:

------------
          ------------
                    ------------
                              ------------

then the labels need to be overlapping by 200 samples.
This code should do it:

(setf stepsize 1000)  ; Number of samples per step
(setf overlap 200)  ; Amount of overlap in samples

(setf maxlabels 1000)  ; Maximum number of labels

(let ((labels ()))  ; initialise an empty list
  (setf overlap (/ overlap *sound-srate*))
  (do* ((counter 1 (1+ counter))
        (ii 0 (+ ii stepsize))
        (jj stepsize (+ jj stepsize)))
       ((> jj len) labels)
    (psetq start (/ ii *sound-srate*)
           end (+ (/ jj *sound-srate*) overlap))
    (push (list start end (format nil "~a" counter))
          labels)))

[stratblue]

Nice one, Steve. Much appreciated. I’ll give that a go ASAP.