>[...] >> UST = Unadjusted System Time > >I believe this is a good introduction to UST/MSC: > >http://www.lurkertech.com/lg/time/intro.html
i read this a year or two ago. it was a major impetus in the design of JACK, because i believe that almost all of it is based on a complete misconception of how to do this stuff, and some of it is just plain wrong. Its worth noting that SGI's "DM" API has never really taken off, and there are lots of reasons why, some technical, some political. the most fundamental problem with SGI's approach to audio+video is that its not based on the desirability of achieving low latency for realtime processing and/or monitoring. its centered on the playback of existing, edited, ready-to-view material. the whole section at the end of that page about "pre-queuing" the data makes this point very clear. SGI tried to solve the problem of the Unix read/write API mismatch with realtime streaming media by adding timestamps to data. CoreAudio solves it by getting rid of read/write, and acknowledging the inherent time-basis of the whole thing, but for some reason keeps timestamps around without using them in many cases. JACK follows CoreAudio's lead, but gets rid of the timestamps. --p
