Why can't After Effects have realtime playback?

What's holding it back?

The nature of the application, that's what.  AE was never, ever intended to work like an editing application.  It was always intended to be a desktop effects, motion graphics and compositing application, working with virtually unlimited layers of footage.

If you tried to do what AE does in Premiere, it would come to a screeching halt and need to render.  If you look at similar applications like Apple's Motion, you won't be playing anything back in real time, either.

Now, that's not to say that there are NO applications that can composite and play in real time: I believe either Flame or Smoke by Autodesk can do it.  The downside: you have to follow Autodesk's precise hardware specifications including pricey and proprietary hardware, you need a boatload of extremely fast storage, and you can't buy Autodesk software: you can only rent it for a 1-year period for a cost of five figures.

Taking that into consideration, I don't think AE looks too bad in comparison.

It's just the way it is and has been forever. It's getting better, though. If and when it works, Fast Preview in CS6 is jaust as good, it's just limited to playing back footage mostly. Any effect still makes things a lot slower...

Mylenium

The GPU makes some things a little bit faster, but the GPU in AE isn't used to render everything where in Premiere it is.  I'm pretty sure AE still runs videos through the CPU and it doesn't use the Mecury Playback/Render engine on anything but the raytraced stuff.

I have a feeling that if adobe wanted to, they could implement a lot of the DirectX 11 features like particles and DoF and stuff that are in the newest or high end realtime technology such as Unreal Engine 4... however, this would leave Mac users out in the cold as Macs don't run DirectX... Sooo... blame Macs.

[cue the rage]

Heck, on my Z820 some projects playback in realtime when I view them as a ram preview (as it renders the first time)..

Bring footage captured in one format into a Premere Pro sequence setup with another format and you'll have to render for realtime playback too. The only time PPro doesn't have to render a preview is when the playback engine and the footage codec match closely enough that the frames don't have to be rendered.

After Effects is specifically designed to mix all kinds of media and as such it breaks down what ever is sent to the timeline into raw pixel values. There was never an attempt to send a codec to a playback engine because AE isn't designed to be a NLE, it's designed to composite mixed media.

Pixels are blended (simple arithmetic mostly) and a new image is constructed a pixel at a time. That's why footage from a highly compressed, cup intensive codec like MPEG4 takes longer to ram preview than a footage from an easy to decompress format like Animation QT. There's less work to do to break the data into pixel values.

Faster processors and GPU acceleration helps this process so AE is faster than it used to be. On my MBPro I get real time preview from 50% sized HD footage from the space bar with a production codec source file unless there are more layers to process. If they are, the preview is very quick and then I can playback as much footage as the available ram will allow.

Same here actually. I'm using Win7 with 8 gigs of RAM and a GTX560 with 2gigs of RAM (with the GFX hack) and a single video plays fine.

The thing I don't get is why when inside a comp, things playback fine, but when you pre-comp that, they go all slow.

And I know AE isn't meant to be an NLE... but something tells me that the fact it can't do some things faster because of of the fact that it's NOT an NLE sounds like an excuse.  That's almost like saying "Well 3DS Max/Maya/Blender can't move quickly because it's not meant to be quick, it's meant to render really high end 3D graphics... If that's the case then I feel like it SHOULD move fast so that the VFX team can hurry and get done wht they need to get done.

ESPECIALLY if I'm just using partical plugins and stuff.

I wonder how AE would work if I had an i5 or i7 CPU with at least 4 HGz, 16 gigs of 1396 DDR3 RAM and an NVIDIA GTX 690. THEN will it be real time?

Dreamcube017 wrote:

 

I feel like it SHOULD move fast so that the VFX team can hurry and get done wht they need to get done.

 

ESPECIALLY if I'm just using partical plugins and stuff.

 

I wonder how AE would work if I had an i5 or i7 CPU with at least 4 HGz, 16 gigs of 1396 DDR3 RAM and an NVIDIA GTX 690. THEN will it be real time?

Actually, particle effects are some of the slowest things to render. Think about it; it's having to animate hundreds of thousands or even millions of things at once. Okay, maybe you're not doing particle effects that are as complicated as mine, but still it's probably thousands of things at once. That's still a lot.

No computer will be real time with After Effects for high end effects. There are basic things you can do (and even some simple particle effects) that will render close to real time on a higher-end machine. I have dual six-core Xeons in my work system with 48 GB of RAM and it's still slow on some of the particle effects I do. It's significantly better than the one I have at home though (single six-core processor, 36 GB of RAM).

The problem is that you have no sense of perspective. It was only a few years ago that a render would take overnight whereas that same effect now renders in about ten minutes (and it even looks better). We have come a very long way in a very short amount of time.

David_MB wrote:

I don't expect it to playback a comp with a ton of layers and effects, but something simple like one chroma keyed video clip and a background should be able to be played back realtime without trouble. It would really speed up the workflow if it did.

Perhaps exerpts from a post Rick Gerard made some time ago on another thread will help explain things to you:

"Sony Vegas, Premiere Pro, Final Cut, Avid are all NLE's (Non Linear Editors) and they are specifically designed to playback a video stream. With any of them, if you stack enough layers or effects on the video, they will have to render a new video stream based on the pixel-based calculations for every pixel in the stack. This rendering, especially for HD sources or for complex plugins, will take a bit of time.

 

After Effects, Flame, Fusion, Shake -- are all pixel-based image processing applications that act very much like Photoshop. They calculate the values of every pixel in every frame, come up with a new pixel, and then play those pixels back as a video stream.

 

AE and all the other pixel-based compositing apps, always work internally with completely uncompressed pixel data. NLE's rely on codecs (and in some cases hardware) to playback the video. It's an entirely different way of working with moving images."

If your workflow requires a real-time playback, use Premiere! It's got a great keyer (or two) in it. And it plays back a video stream without needing to calculate each pixel. If you need to do some more involved keying work, once you've done your edit, import your Premiere project into After Effects and do the keying there. This script can make things even easier.

Note: the advice in this thread is from some very seasoned experts in the field. Mylenium, Rick Gerard, and Dave LaRonde have been working with After Effects for many years before I was - and I've been working in video for over a decade!

Dave LaRonde, you said Motion 'won't be playing anything back in realtime, either'.  Motion does play back in real time and has since it was first created.  I personally use both After Effects and Motion all the time, and After Effects does not play back real time which is the biggest drawback to me.  Motion has to downsample and lower the frame rate, but it does so automatically/dynamically which is a huge benefit.  At just $50, it's surprising that Motion can do this and After Effects can't.  If After Effects would implement this, that would be a huge benefit to the community, thanks!

Oh, you mean the little play button on the viewer that shows you a few seconds before and after the  cursor's current position?  THAT Play button?

Why do you think it moves so slowly until it plays through the that duration one time?  It's building its own RAM Preview.

Apple's Motion has a play button right under the video playback.  You can also press the space bar to start playing.  And it plays in real time, with audio, without having to do a preview.  I use the program every day and it's a big time saver.  If you have effects, replicators, parameters, particle effects, it will play it all back in real time.  The more effects you add, the lower the frame rate gets, but it's surprising how many effects you have to add before the frame rate is an issue.  It's great. Not to mention, you can set your project to loop, and then make your edits as the video plays.  You can edit text in real time, effects, etc.

Motion caches the render in the background while you are working. Motion also gets bogged down very quickly as you stack things up. You can do a lot of things in motion. I actually use motion a lot for some simpler projects, but when you need the power of AE, for now at least, you have to live with the render times. Even on my top of the line, fully decked out MacBook Pro Retina display, motion will drag to sluggish slow to render, not playing back in real time app when a project starts approaching the complexity of most of my AE work.

I have to agree that Motion is great for some things. It's just hopelessly out gunned by AE when the project gets complex.