This is a release of "speakerpipe" and "mikepipe", two command-line audio tools for Mac OS X that show how to use audio in and audio out on Mac OS X. The primary reason for release is to make life a little easier for CoreAudio framework users. The audiopipein and audiopipeout objects make it much easier to do simple audio work than does the CoreAudio framework. The resampler is a quick hack to resample audio since the CoreAudio framework only seems to be able to handle 44.1 kHz. The CoreAudio framework runs a callback in another thread to get samples to send to the speaker and to post data from the microphone. This is much more difficult than usual on UNIX, where doing simple things with audio means just dumping bytes down a pipe to play, or reading from a pipe to record. The functions simulate that, and the command-line tools show an example of usage. ------- Example ------- $ ./mikepipe > record.example (interrupt with control-C) $ ./speakerpipe < record.example You should hear back what you just recorded. ----- Usage ----- usage: speakerpipe [-v] [-c channelCount (1 or 2)] [-s|-u|-f] [-b|-w|-l] [-x] [-r rate] -v : show version and exit -s : signed samples -u : unsigned -f : float -b : 1 byte per sample -w : 2 bytes per sample -l : 4 bytes per sample -x : use opposite endian -r : sample rate, defaults to 44.1 kHz mikepipe uses similar options. -------------- Known Problems -------------- Neither audio in nor audio out has working API to halt the asynchronous thread, so each tool must be terminated with control-C. Need to handle mapping from mono to stereo differently. The hack currently in speakerpipe doubles the resample frequency and diverts every second sample to a different channel. If resampling to a different frequency, this yields different output for the left and right channels. ------- License ------- This code is licensed under a BSD-style license. See the header in any file for more information. Comments to Richard Kiss, <him at richardkiss.com>.
richardkiss/speakerpipe-osx
A pair of utilities to "cat" to the speaker and from the microphone on Mac OS X.