Audacity, PortAudio and ALSA/Linux

A question about Audacity, PortAudio and ALSA: Does Audacity look for either a Jack or PulseAudio connection when running under ALSA/Linux? Does Audacity use the following paradigm, talking to the device through ALSA and bypassing a Jack/PulseAudio connection?

Audacity<->Portaudio<->Alsa

Thank you.

Audacity, via Portaudio, searches for all available sound systems. You can then select the host and device in the device toolbar. For example, ALSA devices usually have names such as “device descriptor (hw:0,0)”. To use Jack Audio System, it must be running before you launch Audacity, then select Jack as the “host” and all available jack “ports” will be listed in the input/output selectors of the device toolbar.

I got PortAudio to record audio using ALSA – sort of – despite a major error in the PortAudio documentation. I am still not completely successful in this, however, so I have to ask these questions here because PortAudio recording with ALSA does work on Audacity and I am getting no help on the PortAudio mailing list.

Under ALSA, what are the values Audacity uses for FramesPerBuffer (I’m thinking it is maybe 512?)

What is the suggested latency used for ALSA PortAudio in Audacity? I need to know the exact number of milliseconds, not something like “defaultLowInputLatency”

Thank you.