SuperCollider: Buffers & Samples

Buffers are a tool to hold data arrays on the server and can be used for recording, loading and playing audio files (SC Documentation on Buffers).

SuperCollider comes with a couple of builtin audio samples, which are used in most of the SC helpfiles and examples. The following snippets work with extra audio samples that can be downloaded here: http://ringbuffer.org/download/audio/MFB-522/ They need to be located in the current SC working directory.

Reading Mono Files

The following code creates a client-side object b, that points to a buffer on the default server s - and loads the wav-file kick_1.wav into the buffer:

b = Buffer.read(s, 'kick_1.wav');

When the wav-file has been read, we can get information on the buffer and the sample inside. Like nodes and buses, buffers are known to the server only by their index - the buffer number. We can query this buffer's number:

b.bufnum

There is more information we can get about the sample once it is loaded on the server:

b.numChannels;
b.sampleRate;
b.numFrames;
b.path;

Single Shot Sampler

The sampled audio file in a buffer can be played with the PlayBuf UGen. Since the wav's sample rate and the sample rate of the SC server are not necessarily the same, we need to take care that the playback-rate is adjusted accordingly. The buffer-to-server ration can be calculated in the language (b.sampleRate/s.sampleRate) or using a dedicated UGen:

// PlayBuf args: numChannels, buffer (buffer number), rate
x = {Out.ar(0, PlayBuf.ar(1, b, BufRateScale.kr(b))) }.play;

Note that the node remains on the server and needs to be freed with x.free.