On 05/08/2012 05:07 AM, Egor Sanin wrote: > Hi folks. Hi Egor,
> I've got a question about SMPTE frames and jack period size. > In the "worst case" of 30 frames/second, each frame spans 1/30 seconds. > Does that mean that if jackd is called such that (period size)/(rate) > ≥ (1/30) seconds, we will drop SMPTE frames? s/drop/skip/ JACK does not know anything about SMPTE, does it? It counts audio-frames. JACK-transport timecode (as returned by jack_transport_query()) increases in steps of the period size. It depends on the application what to make with this. jack_frame_time() OTOH estimates the time and includes the offset jack_frames_since_cycle_start(); but I don't know how accurate this is. @Paul, Fons,..: does it use a PLL or simply return the difference from clock_gettime() since the beginning of the cycle? IIRC Fons reworked some of jack timing functions not too long ago when writing zita-a2j, zita-j2a, but don't know if they also affect the transport API. > Large period sizes are rare these days, but this is still a possible > scenario and I want to understand it properly. Where does the SMPTE come into play? MTC? robin _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev