URN's in house low latency outside broadcast receiver/transmitter for Linux and OSX. OB One uses the OPUS codec to reduce tranmission size at relative low cost to audio quality.
Tested on Debian and Arch based Linux Distributions. RX tested on Raspberry Pi models B+ and 2. For TX capabillities an additional soundcard such as Cirrus Logic Audio Card required.
Tested on OSX 10.10 (Yosemite).
Opus Codec http://www.opus-codec.org Portaudio http://www.portaudio.com ALSA (Linux only) http://www.alsa-project.org
For a quick installation of dependecies on Linux use your package manager, for example for Debian based distros:
apt-get install libopus-dev libasound2-dev portaudio19-dev
and for OSX users (who have macports installed)
port install portaudio libopus
Clone reposity via git clone https://github.com/urn/ob_one.git and browse into the operating system directory of choice. From the terminal run the command:
make
and then sudo make install
tx [options] [destination]
rx [options]
Flags follow standard GNU convention.
-b -B -c -d -f -p -q -r -v
b: Bytes per frame per channel (default 96) Sets the desired size of bytes OPUS should convert a frame of audio.
B: Buffer size (RX only, default 50) Sets the size of the playback buffer in milliseconds.
c: No. Channels (default 2) sets between mono and stereo.
d: Device (default 0) integer value which selects the audio output to send audio to. Set this value to 0 use the OS default (which can be set in your OS sound settings).
f: Frame size (default 480) set in bytes the size of the audio frame to be passed onto OPUS for conversion. For example a 480 byte frame with a sample rate of 48000 Hz equates to 10 ms of audio. Note: Due to OPUS contraints the frame size can only be 120,240,480,960,1920 or 2880 bytes.
p: Port No. (default 1350) Set the port number to send the tranmission/listen to the transmission on. Only one TX/RX per port.
q: Quiet mode.
r: Sample rate (default 48000) sets the record and playback sample rate of hardware in Hz.
v: Verbose mode.