19 Mar
2005
19 Mar
'05
12:29 p.m.
On Fri, Mar 18, 2005 at 11:34:34PM +0100, Jens M
Andreasen wrote:
correct. SMPTE provides positional sync with a resolution of 1 SMPTE
frame (on the order of 1/30th second) - in other words, appalling for
audio synchronization.
MIDI SPP provides positional sync with a resolution based on a tempo
map. Nice for musical sync, terrible for audio.
Do jack-transport support SMPTE
Do jack-transport support MIDI song pointer
(guessing yes to above)
actually i beleive the answer is mostly no, although perhaps
its best to consider smpte and midi as paralle rather than
being supported by jack-transport. Fons Adriaensen was working on this. Theoretically,
smpte lock
between 2 stable systems could be quite tight, but not only is
it not as tight as Jack, it is way too complicated and cpu intensive.
not entirely true. using a DLL for this is not very expensive and can
be rather accurate. but you are right that it still cannot provide
sample level sync.
the reason i asked about jack-transport in relation to
bio2jack
is that there are several unasked question on the mplayer lists
re how to get this working. People dont realise that bio2jack
only provides "jack 1.0 simple" or whatever you want to call it.
but thats for a very obvious reason: there is nothing in any of the
blocking i/o models that bio2jack is there to assist with that
corresponds to the notion of a transport model. what OSS or ALSA calls
would an application be making to do something like this? answer:
none. therefore, bio2jack doesn't so much provide "jack 1.0 simple" as
"blocking i/o via JACK". if you want transport stuff, you need an API
that has no analog in OSS or ALSA. AFAIK, for Linux at least, JACK is
the only API that provides such a concept.
--p