PortAudio.jl

This module offers realtime audio input and output in Julia based on the PortAudio library. It is still under heavy development and not well documented, yet. See the examples/ folder to get an idea of how to use it. Feedback and contributions are welcome!

Basics

• use PortAudio.list_devices() to print an overview of available devices and their device IDs
• use PortAudio.get_devices() to retrieve an array of device info structures
• PortAudio.initialize() and PortAudio.terminate() will be called
  automatically by all PortAudio.jl high-level API functions. However, it can be called manually to trigger device initialization at a specific instant, too.

NOTE: Buffer underflows/overflows may occur when a script is run for the first time due to JIT compilation.

Playback

# create a random noise signal
x = convert(Array{Float32}, randn(MersenneTwister(),sample_rate*3,2))
x = x ./ 10

# simply play a single buffer
play(x, sample_rate)

# open a stream and play the audio
devID = -1 # default device
stream = open(devID, (0, 2), sample_rate, buf_size)
write(stream, x)
close(stream)

Recording

# simply record a few samples
y = record(2*sample_rate, 2, sample_rate)

# open a stream and record a few seconds
devID = -1 # default device
stream = open(devID, (2, 0), sample_rate, buf_size)
z = read(stream, 2*sample_rate)
close(stream)

Simultaneous playback and recording (duplex stream)

# create a random noise signal
x = convert(Array{Float32}, randn(MersenneTwister(),sample_rate*3,2))
x = x ./ 10

# simply play a single buffer and record simultaneosly
y = playrec(x, sample_rate)


# use default device
devID = -1
# or retrieve a specific device by name
#devID = PortAudio.find_device("default")

# open a duplex stream (not supported on all host API...)
# and read and write at the same time
stream = open(devID, (2, 2), sample_rate, buf_size)
z = readwrite(stream, x)
close(stream)

Credits

Most parts of the low-level PortAudio interface was taken from the AudioIO.jl module.