Do you have El Capitan?
Yes. Honestly, AE CC 2015 is so full of bugs. It's unfortunate, because when it works - it works great. But then everything comes to a standstill.
I can't believe Adobe released this as an alpha product. They forced all of us real-world users to become inadvertent beta-testers - without telling us. It was very poor business policy on the part of Adobe.
The audio implementation is a complete mess. Yes, I know AE is not "audio" software - but it's no longer even possible to time animations to a music scratch-track. And that's just not acceptable in a real-world animation/broadcast design production environment.
I figured. I know a lot of folks on El Capitan are having issues with playback with CC 2015.
Have you tried CC 2014 yet? Your Creative Cloud subscription gives you access to CS6, CC, CC 2014, and CC 2015.
What is the frame rate of your composition? What is the size of your composition. There are lots of folks trying to do 59.94 comps because they are shooting 60P video with their cameras. Personally I think that is a waste of time for most projects. Try this for an HD comp. Set your Zoom factor, the first option on the bottom of the Composition Panel to 50%, set your resolution to Auto, then set the frame rate in the Preview panel to 29.97 (if your comp is 60P or 59.94 fps). If that doesn't solve the problem let us know. If you are trying to preview a 4K comp then set the zoom factor to 25%. If that still doesn't work try skipping 1 frame in the preview panel. I can easily get an older Mac Mini (2011) with 16gb ram and running OS X 10.11.1 to playback a 29.97fps 1920 X 1080 comp in real time.
I might have to go back to CC 2014 (yes, it works) but I actually prefer CC 2015 WHEN it does work. Are there more fixes coming to CC 2015?
I'm not shooting 60p. I've got my audio track, a couple of AE adjustment layers and some imported TIFF sequences from C4D.
Honestly, it's a bug. And it's strictly related to the audio. It has something to do with the sample rate. I tried many different configurations - adjusting both the sample rate of the AE file and the sample rate of the audio file. Sometimes the preview is smooth - mostly it's slowed down and distorted. I can turn off all the other layers (eyeball off) and the audio is distorted - but if I delete the additional layers, it plays smoothly - but only sometimes.
There's something off in the source code of the After Effects app.
One of the guys from Adobe was talking about playback issues and said they needed more info and bug reports from people having problems so they could have better fixes for an update in a couple of months. (Or was it a few months?) If memory (and history) serves, there's usually a sizeable update a couple of weeks after NAB in April, so surely by then!
Yes, it's a bug. Rick was just giving you some ways to work around it in the meantime until it gets fixed.
As you point out, something is awry in AE's code. That's because that's brand new code doing brand new things and it's not done yet. The AE team is completely redoing the core architecture of AE in an attempt to make it take advantage of modern hardware and be faster, but they're not done. If you think of CC 2015 as a kind of beta, I find it's a lot less frustrating. As you've said, when CC 2015 works, it's great! I agree. I use it almost exclusively at my home office. Having the UI and renderer on separate processing threads makes a huge difference in working. We don't have to wait for the renderer to catch up with us; we can just carry on working! Hopefully they'll have the new renderer in place soon so AE can be complete again!