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Jack Transport February 21, 2010

Posted by audaspace in Jack.
comments closed

Yay! It’s done! Blender 2.5 now supports the often requested feature jack transport!

What’s that? That’s an awesome thing with which you can syncronize audio applications over the pro-audio server jack. That means you can edit your animations in blender while having the audio in one of the pro-audio tools that work with jack like ardour. And when you play back, they will be perfectly synchronized.

How to use it:

Make sure you properly set up jack and have the server running. Then in blender set the output device to Jack under the System tab of the User Preferences (Ctrl + Alt + U). Last but not least you have to set the sync mode dropdown in the timeline window to AV-sync.

I wanted to do a short demonstration video, but unfortunately the recording FPS of recordmydesktop are much too low on my PC.


AV-sync February 18, 2010

Posted by audaspace in Jack, Sequencer.
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Hi there!

Got yet another one:

  • Recode of the Sequencer Audio System for better Audio-Video synchronisation.

First I had a quite huge change in mind to the blender timing code: http://wiki.blender.org/index.php/User:NeXyon/TimerAPI . That would perfectly support jack transport. But talking with Ton I realized that it’s not so good to do this way.

So the final implementation was pretty quick and easy, thanks to my hard design work before starting implementation. I’m quite happy that pays off now.

Disadvantage is, that jack transport is not as easy to implement now. But I think I might still be able to do it, so jack fans: Stay tuned.

Summing up, this is an important date for blender 2.5 audio, as all audio features that were supported in 2.49b are back now! Time to celebrate!


Realtime for Jack February 11, 2010

Posted by audaspace in Jack.
comments closed

Yeah, the jack backend of blender is becoming useful with that done. Unfortunately the ring buffer used adds a little latency, so you actually can’t call it “realtime”, but at least you don’t get any xruns anymore, as the process callback of jack is now non-blocking and pretty fast. Moreover the latency added now won’t matter anymore when jack transport is implemented as I’ll be able to remove the latency when it is enabled.

Time to strike through the next point on the todo list:

  • Realtime support.

So we’re one step close to jack transport support. Ton promissed to instruct Brecht and/or Campbell to do an API for external timers to get AV sync working. They will talk to me when that’s going to be worked on. We will then create an API that is just perfect for jack transport and that will bring us just one little step further to jack transport support.