[LAD] Deciphering jack-smf-utils -- Jack MIDI stuff

From: M Donalies <ingeniousnebbish@email-addr-hidden>
Date: Sun Feb 17 2013 - 05:33:50 EET

I haven't really looked at the recorder program, but the player is pretty
cool.

To make it easier for me to understand, I simplified the code somewhat (got rid
of lash stuff, reduced output to a single port, etc) so my code excerpts below
don't match up exactly with the original code.

The first question is a rather stupid one: How long is a Jack frame? If we're
running at 44.1 kHz, is a frame 1/44100 sec? Or is it some multiple? Or is it
something else? And does the process callback get called at each frame while
transport is rolling?

process_callback() calls process_midi_output(), wherein we find:
        port_buffer = jack_port_get_buffer(output_port, nframes);
Why the nframes parameter? Is there a separate buffer area for each frame?

A little later in the same function we have:
        last_frame_time = jack_last_frame_time(jack_client);
Is this the time of the end of the last process cycle?

-- 
7:8
_______________________________________________
Linux-audio-dev mailing list
Linux-audio-dev@email-addr-hidden
http://lists.linuxaudio.org/listinfo/linux-audio-dev
Received on Sun Feb 17 08:15:01 2013

This archive was generated by hypermail 2.1.8 : Sun Feb 17 2013 - 08:15:01 EET