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dunnlights
25-06-2008, 02:20 PM
Hey,

I'm running 2 cats in sync, and when I plug and unplug my headphones on the 1st cat, I'm OK, but when I do it on the second cat, it causes the audio to fall out of sync. Any thoughts?

emilianomorgia
26-06-2008, 03:34 AM
Hey,

I'm running 2 cats in sync, and when I plug and unplug my headphones on the 1st cat, I'm OK, but when I do it on the second cat, it causes the audio to fall out of sync. Any thoughts?

I don't know if this changed on lasted release but as far I remember you can't sync two movies if you play it in AUDIO PLAY mode .

Read this :


playing audio on a single computer is easy-

but you cant sync when playing audio and video from a movie file.
it doesnt work.

audio takes total priority - as it should.
this is how this stuff works.

quicktime does all sorts of behind the scenes wrangling to make sure this happens - that i have no access to...



http://chaldee1.gotadsl.co.uk/~richardb/upload/showthread.php?t=945&highlight=audio+sync

SourceChild
27-06-2008, 12:11 AM
I don't know if this changed on lasted release but as far I remember you can't sync two movies if you play it in AUDIO PLAY mode .


Actually, I used to do this all the time and it worked. On G5 machines, it dropped frames like crazy on the slave machines but it still worked.

My suggestions is to not use the sync ID but to have the Audio file output timecode and then sync the other Cat machines to the timecode instead. Then make sure you are using a re-rendered lower rez video file with the audio uncompressed.

If you have Mac Pro machines and fast disks, it should work fine but remember that Catalyst is merely and application of many and not something with dedicated processing priority.

Audio works but be very sure you have a clean machine.


Incidentally, the reason Audio skips on the 2nd Mac is due to a process in the kernel that switches the audio from front to back output. When you plug and unplug, a process has to run to switch the output before the audio can be rendered to it.

The reason you didn't notice on the first machine is that perhaps it switched fast enough to hide any artifacts.

The best suggestion is to use an external mixer with a headphone plug. I have a lexicon box with a high quality ADC and DAC which is connected when I use Audio. This way I can disable the on board audio and increase performance.

If you want to keep to the cost effective solution of continuing to use the mini headphone jack, just remember not to use headphones during a show if you will unplug them.

samsc
27-06-2008, 03:53 PM
I don't know if this changed on lasted release but as far I remember you can't sync two movies if you play it in AUDIO PLAY mode .

Read this :





http://chaldee1.gotadsl.co.uk/~richardb/upload/showthread.php?t=945&highlight=audio+sync

you cant sync in play audio - because apple controls everything in this mode.

samsc
27-06-2008, 03:58 PM
Hey,

I'm running 2 cats in sync, and when I plug and unplug my headphones on the 1st cat, I'm OK, but when I do it on the second cat, it causes the audio to fall out of sync. Any thoughts?

apple is entirely responsible for things like this -

todd suggests a mechanism or a reason - but he might not be correct.

it could be any number of things -its something internal to sound management and quicktime.

SourceChild
28-06-2008, 10:58 PM
todd suggests a mechanism or a reason - but he might not be correct..

Richard is correct. Don't take what I say completely to heart.

My source is articles I read on different forums and apple support. There is no documentation outlining my statements other than a consensus in discussion from Mac users.

The problem with any high level operating system is that sometimes the way objects are called to initiate different applications causes subtle priority changes in how processing resources are allocated and prioritized to the applications.

The two workarounds I suggest are to:


"Leave it alone." Don't change or unplug anything in a show environment.
Keep your system clean and reload a fresh disk image from time to time.


Here is a crude analogy for those who don't really care about the technical workings of an OS. A computer operating system is kind of like a mind. As you change things, new pathways replace older ones and sometimes the new pathways might be more efficient for certain processes and less for others.