portaudio

I have a lab project that uses mainly PyAudio and to further understand its way of working I made some measurements, in this case time between callbacks (using callback mode). I timed it, and got an interesting result (@256 chunk size, 44.1k fs): 0.0099701;0.0000365;0.0000201;0.0201579 This pattern goes on and on. Between two longer calls, we have two shorter calls and sometimes the longer call is shorter (mind you I don't do anything else in the program than time the callbacks) . If we average this out we get our desired callback time: 1/44100 * 256 (roughly 5.8ms) Here is my measurement

I'd like to query my audio device and get all its available sample rates. I'm using PyAudio 0.2, which runs on top of PortAudio v19, on an Ubuntu machine with Python 2.6. In the pyaudio distribution, test/system_info.py shows how to determine supported sample rates for devices. See the section that starts at line 49 . In short, you use the PyAudio.is_format_supported method, e.g. devinfo = p.get_device_info_by_index(1) # Or whatever device you care about. if p.is_format_supported(44100.0, # Sample rate input_device=devinfo['index'], input_channels=devinfo['maxInputChannels'], input_format

I'm using PyAudio under the Enthought Python Distribution (Python 2.6.6) in Ubuntu 10.10 x64. >>> import pyaudio >>> pa = pyaudio.PyAudio() >>> pa.get_default_input_device_info() Traceback (most recent call last): File "<pyshell#24>", line 1, in <module> pa.get_default_input_device_info() File "/usr/lib/python_epd/lib/python2.6/site-packages/pyaudio.py", line 936, in get_default_input_device_info device_index = pa.get_default_input_device() IOError: No Default Input Device Available This is the same error I get if I try to open an input stream. There is the corresponding error "IOError: No

I want to make a program that would record audio data using PortAudio (I have this part done) and then display the frequency information of that recorded audio (for now, I'd like to display the average frequency of each of the group of samples as they come in). From some research I've done, I know that I need to do an FFT. So I googled for a library to do that, in C, and found FFTW. However, now I am a little lost. What exactly am I supposed to do with the samples I recorded to extract some frequency information from them? What kind of FFT should I use (I assume I'd need a real data 1D?)? And