CSC111 Basic JES Sound Functions
--D. Thiebaut (talk) 10:16, 24 February 2014 (EST)
JES Sound Functions
This is just reference material taken from Depaw U. that you may want to play with.
A sound is treated as a collection of sample values, much as a picture is a collection of pixels. Here are the functions on sounds:
| makeSound(file) | Return a sound loaded from a WAV, AU, or AIFF file |
| makeEmptySound( noSamples) | Return a blank sound (all samples values are 0) with that number of samples |
| writeSoundTo(s, file) | Save s in the given file; uses the same format as when loaded (makeEmptySound creates a sound in WAV format) |
| openSoundTool(s) | Open the sound exploration window for s |
| play(s) | Play sound s in the background |
| playAtRate(s, r) | Play s at speed r--1.0 is normal, 2.0 is twice as fast, etc. |
| playInRange(s, b, e) | Play s from sample number b to e |
| playAtRateInRange(s, r, b, e) | Play s from b to e at speed r |
| blockingPlay(s) | Play s and wait for it to finish (also, blockingPlayInRange and blockingPlayAtRateInRange) |
| getSamples(s) | Return the collection of samples in s (not quite a list, but indexable and usable in a for loop) |
| getLength(s) | Return the number of samples in s |
| getSamplingRate(s) | Return the number of samples per second in s |
There are also some useful methods on sound and sample objects:
| s.getSampleValue(i) | Return the (left channel, if stereo) value of the ith sample in s (the first sample is at index 1) |
| s.getLeftSampleValue(i) | Return the left channel value at index i |
| s.getRightSampleValue(i) | Return the right channel value at index i |
| s.setSampleValue(i, v) | Set the (left) value of sample i to v; the range of sample values is -32,768 to +32,767 |
| s.setLeftSampleValue(i, v) | Same |
| s.setRightSampleValue(i, v) | Guess what? |
| s.getSampleObjectAt(i) | Extracts the sample object at index i, without creating a whole collection of samples |
| samp.value | Return the value of sample samp; change the value by assigning to this |
| samp.left | Return or change the left channel value of samp |
| samp.right | Return or change the right channel value of samp |
Finally, JES provides a simple function to play a MIDI note:
| playNote(n, dur, vol) | plays note number n (middle C is 60, C-sharp is 61, etc.; the range is 0-127) for dur milliseconds at volume vol (maximum is 127). |
The function pauses execution until the note is finished. For much more complete support of MIDI music, see the next section.
