cannam@124: README for PortAudio Loopback Test
cannam@124: 
cannam@124: Copyright (c) 1999-2010 Phil Burk and Ross Bencina
cannam@124: See complete license at end of file.
cannam@124: 
cannam@124: This folder contains code for a single executable that does a standalone test of PortAudio.
cannam@124: It does not require a human to listen to the result. Instead it listens to itself using
cannam@124: a loopback cable connected between the audio output and the audio input. Special pop detectors
cannam@124: and phase analysers can detect errors in the audio stream.
cannam@124: 
cannam@124: This test can be run from a script as part of a nightly build and test.
cannam@124: 
cannam@124: --- How to Build the Loopback Test ---
cannam@124: 
cannam@124: The loopback test is not normally built by the makefile.
cannam@124: To build the loopback test, enter:
cannam@124: 
cannam@124:   ./configure && make loopback
cannam@124:   
cannam@124: This will build the "bin/paloopback" executable.
cannam@124:   
cannam@124: --- How To Run Test ---
cannam@124: 
cannam@124: Connect stereo cables from one or more output audio devices to audio input devices. 
cannam@124: The test will scan all the ports and find the cables.
cannam@124: 
cannam@124: Adjust the volume levels of the hardware so you get a decent signal that will not clip.
cannam@124: 
cannam@124: Run the test from the command line with the following options:
cannam@124: 
cannam@124:   -i# Input device ID. Will scan for loopback if not specified.
cannam@124:   -o# Output device ID. Will scan for loopback if not specified.
cannam@124:   -r# Sample Rate in Hz. Will use multiple common rates if not specified.
cannam@124:   -s# Size of callback buffer in frames, framesPerBuffer.
cannam@124:   -w  Save bad recordings in a WAV file.
cannam@124:   -dDir  Path for Directory for WAV files. Default is current directory.
cannam@124:   -m  Just test the DSP Math code and not the audio devices.
cannam@124: 
cannam@124: If the -w option is set then any tests that fail will save the recording of the broken
cannam@124: channel in a WAV file. The files will be numbered and shown in the report.
cannam@124: 
cannam@124: --- ToDo ---
cannam@124: 
cannam@124: * Add check for harmonic and enharmonic distortion.
cannam@124: * Measure min/max peak values.
cannam@124: * Detect DC bias.
cannam@124: * Test against matrix of devices/APIs and settings.
cannam@124: * Detect mono vs stereo loopback.
cannam@124: * More command line options
cannam@124:    --quick
cannam@124:    --latency
cannam@124:    --duration
cannam@124: * Automated build and test script with cron job.
cannam@124: * Test on Windows.
cannam@124: 
cannam@124: 
cannam@124: /*
cannam@124:  * PortAudio Portable Real-Time Audio Library
cannam@124:  * Latest Version at: http://www.portaudio.com
cannam@124:  *
cannam@124:  * Copyright (c) 1999-2008 Phil Burk and Ross Bencina
cannam@124:  *
cannam@124:  * Permission is hereby granted, free of charge, to any person obtaining
cannam@124:  * a copy of this software and associated documentation files
cannam@124:  * (the "Software"), to deal in the Software without restriction,
cannam@124:  * including without limitation the rights to use, copy, modify, merge,
cannam@124:  * publish, distribute, sublicense, and/or sell copies of the Software,
cannam@124:  * and to permit persons to whom the Software is furnished to do so,
cannam@124:  * subject to the following conditions:
cannam@124:  *
cannam@124:  * The above copyright notice and this permission notice shall be
cannam@124:  * included in all copies or substantial portions of the Software.
cannam@124:  *
cannam@124:  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
cannam@124:  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
cannam@124:  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
cannam@124:  * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
cannam@124:  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
cannam@124:  * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
cannam@124:  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
cannam@124:  */
cannam@124: 
cannam@124: /*
cannam@124:  * The text above constitutes the entire PortAudio license; however, 
cannam@124:  * the PortAudio community also makes the following non-binding requests:
cannam@124:  *
cannam@124:  * Any person wishing to distribute modifications to the Software is
cannam@124:  * requested to send the modifications to the original developer so that
cannam@124:  * they can be incorporated into the canonical version. It is also 
cannam@124:  * requested that these non-binding requests be included along with the 
cannam@124:  * license above.
cannam@124:  */