Working with stereo and mono track

For the stereo track it shows two channels in which the position of sample points differ, is there any way to select any single channel, either left or right ?
We want to work on the selected channel so can you please tell us the nyquist code for selecting the channel.

Thanking you.

The easiest way to work with one channel of a stereo pair is to split the pair into two separate tracks. See:

To work with stereo tracks in Nyquist, use the AREF command
See here for more information:

By the way, how are you getting on with:

We have retrieved the time values at a particular instance refering to the topic “Beats Per Minute”.

Moving to my next query, I want to get 44100 samples per second. How do i get those many samples?
And also, after getting those many samples, how do i iterate through each of the sample? snd-fetch does not satisfy my need.

I have put this code in the do loop so that i iterate through the samples

(setq p (< v thres))
  (setq time (+ time 0.001))
  (setq v (snd-fetch s2)))

I expect 441 samples in 10 milli seconds but I am getting only 12.

So how do I proceed with the coding to achieve the result?

Thank you :slight_smile:

Look at your usage of SND-FETCH
What values is it actually getting and where is it getting them from?

Can u please explain us the exact use of snd-follow & force-srate in your own words. We already reffered the links, but we are not getting it.
Please can u help us with this ?

FORCE_SRATE changes the sample rate of the sound to the specified sample rate.
(force-srate 1000 sound)
changes the sample rate of “sound” to 1000 samples per second.

SND_FOLLOW produces a control signal that rides over the top of the peaks of a sound.
This takes several parameters to define precisely how it does this, but the basic idea is to create an “envelope” that follows the contour of the sound waveform.

(let ((floor 0.001)
      (risetime 0.1)
      (falltime 0.5)
      (lookahead 4410))
    (snd-follow s floor risetime falltime lookahead))

The upper track shows the input sound. The lower track shows the resulting “envelope”.
Note how the envelope “follows” the shape of the input audio, but is offset by 4410 samples.


Thank you so much for guidance. I located the beats for different rhythms.And also calculated tempo(beats per minute). Is there any function available to take more than one sound clip as a input? I want to take more than one sound clip as a input and calculate tempo of those then sort according to their increasing tempo and create a playlist. Please can you help me?

Thanking you.

In Audacity you can only select one “region” at a time, but you can select the same time region in multiple tracks (see:

When using Nyquist effects, the audio from one track is sent from Audacity to Nyquist for processing and Nyquist then returns a “result” (which may be a sound, labels, text, or nothing). If there are multiple tracks selected, this is repeated one track at a time for each track.