Where is the bottleneck when rendering out of AE CS6?

[Phil Bates]

I am doing some simple rendering of 5K R3Ds, converting them to HD mp4 movies using AE6. My hardware is a relatively new 12 core Mac with 32gb of RAM. We are rendering across a network with gigabit ethernet and only getting 1 frame rendered every 6 seconds. The activity monitor shows no strain on network bandwidth, cpu usage (only using 3-5 cores out of 12) or anything else significant.

What could be the be the bottleneck? I am looking for general answers of known issues, not necessarily a detailed custom troubleshoot.

Would a PC be significantly faster for this application?

Thanks for your help,

Phil

[Alexander Mejia]

You could load the system with bootcamp and run AE CS6 in Windows. I have heard that Adobe products tend to run a little faster in Windows, but I can't imagine the performance difference being any different than 5%

For rendering, try to turn on the multi-core rendering and make sure enough ram is dedicated to each core. Under preferences --> Memory & Multiprocessing change the "Render Multiple Frames Simultaneously" tickbox. Sometimes it speeds up things, sometimes it slows down a render. Always make sure you've dedicated an adequate ammount of ram per background CPU. I would say at least 2gb per process.

Also keep in mind that the render you're describing could have multiple bottlenecks:

How large is the data set for each frame you're trying to pull? Do you have some 3+ layers in a single frame?
How limited is your Disk I/O? Is this a single laptop drive, or a huge raid box?
Is Multiprocessing turned on? You could be choked at just trying to render one frame at a time instead of multiple.
Is the After Effects H.264 encoder multi threaded? I've never rendered anything out of AE except Tiff and DPX sequences.

I've had better performance in some situations rendering to an image sequence, and then packaging up that image sequence as a h.264 render in Premiere. This requires a lot of Disk I/O so make sure you are attached to a fast raid or SSD cluster if you go this route.

[PatrickFaith]

I have a render in AE that is running around the same rate today (7 seconds per frame) ... I normally find it's some ae effect that makes things go linear (i.e. some of the camera blurs have a huge difference from normal blurs). Anything to do with stabalization or time differencing can do that (i.e. if you have movement blur checked on the output). My current render needs to do two time differences, pipelined with two keys, which is the reason why it's going slow ... but if you have motion blur checked that also requires frame differencing. Sometimes openexr and png serializes things on output (so you don't use all the cpu's ... depending on how your pipeline is hooked up - normally try to have enough composites chaining that this isn't my slow point).

I am still waiting for my 1.5 minutes to render ... been waiting 5 hours ;) [this entire run is just to modify some glass glare ... ughh ]

[Les C.]

I have a render in AE that is running around the same rate today (7 seconds per frame) ... I normally find it's some ae effect that makes things go linear (i.e. some of the camera blurs have a huge difference from normal blurs). Anything to do with stabalization or time differencing can do that (i.e. if you have movement blur checked on the output). My current render needs to do two time differences, pipelined with two keys, which is the reason why it's going slow ... but if you have motion blur checked that also requires frame differencing. Sometimes openexr and png serializes things on output (so you don't use all the cpu's ... depending on how your pipeline is hooked up - normally try to have enough composites chaining that this isn't my slow point).

I am still waiting for my 1.5 minutes to render ... been waiting 5 hours ;) [this entire run is just to modify some glass glare ... ughh ]

You might try RSMB and see if that speeds you up, or at least gives you better quality for your long render?

http://www.revisionfx.com/products/rsmb/overview/

[Danko Dolch]

Hi Phil,

the bottleneck is AE itself - it's a motion graphics and compositing app dev. to render 100 frames here and 200 frames there but not to process large sets of clips. Of course it could be really fast if it would use things like the Adobe MPE - but currently it doesn't.

"...some simple rendering of 5K R3Ds, converting them to HD mp4 movies using AE6..."

Don't use AE for that. If you just want to make mp4 encodings use Adobe Premiere instaed and ensure that you are using the GPU accelerated Mercury Playback Engine - otherwise you need some additional hours just for the propper rescaling with "Maximum Render Quality".

If you are using a MAC - ensure that your GPU is performant enought for this task.

Adobe Premiere will speedup things dramatically - also think about a RED Rocket card if you need another speed boost...

You could also think about using Adobe Speedgrade to render the R3D to Quicktime and transcode them with Adobe Media Encoder to MP4...

best Regards

Danko

[Phil Bates]

Thanks everyone for your responses. I greatly appreciate it.

We ran a test on an 8-core PC and got better than 2x speed on rendering. We can no longer ignore the difference between Mac and PC, and will be testing on a faster PC to help us learn how to configure some PC rendering stations.

We need to do the MP4 conversions in AE for two reasons: 1. We are using AE to match color correction between multiple plate shots, it's somewhat complex, involves nested comps, etc. Can't do in RCX or Premier. 2. The idea of rendering QT movies in AE, and then converting them to MP4 in another application complicates and slows down our work flow, not to mention the 2GB rendering limit across a network. We need raw rendering speed and it looks like PCs are the best answer.

Again, thanks! :)

Phil

[Danko Dolch]

Hi Phil,

If you have to stay with AE then ensure that you don't have to wait for your HDD and use a fast SSD as AE temp drive - as long as your CPU usage is near 100% all you can do is to get even faster CPU or eventually use a RED Rocket card.

A powerful Win7 PC workstation seems to be a good platform to run AE on...

Just to get an idea of what would be possible try to test a R3D to MOV conversion with Speedgrade and a powerful GPU - and Speedgrade only uses one GPU and one CPU... ;-)

[Alexander Mejia]

We need to do the MP4 conversions in AE for two reasons: 1. We are using AE to match color correction between multiple plate shots, it's somewhat complex, involves nested comps, etc. Can't do in RCX or Premier. 2. The idea of rendering QT movies in AE, and then converting them to MP4 in another application complicates and slows down our work flow, not to mention the 2GB rendering limit across a network. We need raw rendering speed and it looks like PCs are the best answer.

Be super careful of using color management in After Effects. I believe you can render non rec.709 video to your .mp4 file. It will most likely not state what color space you rendered in, and to make things worse, most applications ASSUME rec.709 is in a .mp4 container, even if metadata is set specifically stating otherwise.

If you render in premiere it will handle the conversion of RAW RGB to rec.709. As long as you render an image sequence with a color space Premiere Pro handles properly, it will make it into that .mp4 as rec.709 without any weird color shifts.

Now if you're trying to render to a .mov container, throw any logic out the window since that's another nightmare to handle.

[Danko Dolch]

Be super careful of using color management in every application where you have to deal with source profiles, working space profiles, display profiles and output profiles - it becomes complex some times ;-)

That means that you have to apply a rec.709 output profile before sending the video to the H.264 encoder.

as long as Premiere isn't color managed it will do nothing at all - if you input and output 10Bit RGB DPX - you can deal with all color spaces you like - if you work with dependent codecs that do internal conversions - assuming you are processing rec.709 you should be careful...

[Phil Bates]

Thanks guys.

We borrowed a powerful PC and found that a 5 hour render on a Mac takes 1 hour on the PC. Definitely worth the investment! So far, no color issues.

Thanks again,

Phil