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Help! Unusual long render time in AE CS3

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Tung Bui
Help! Unusual long render time in AE CS3
on Sep 22, 2009 at 7:46:04 am


I'm having a very frustrating problem rendering out a clip in AE CS3.

The situation:
- the input clip format is .m2v (MPEG2-Bluray format), it's about 4 minutes long
- the comp has 2 layers (one is the clip, another is some simple text)
- no other effects are applied
- no motion blur
- My PC specs: Core i7 920 CPU, 6 GB of DDR3 RAM, nvidia 9800gx2, Win Vista x64 Ultimate

The problem:
- render time is almost 6 hours.. I'm rendering out to the MPEG2-Bluray preset
- even though I still get very good speed with RAM preview
- I have done similar renders before and they only took about 1-2 minutes

What I've tried:
- I tried restarting AE and the PC several times... no luck
- I've created another empty comp, throw in some footage and render out, it doesn't matter what format they are, AE renders at about 5-10 seconds per frame!
- I've tried rendering to different physical hard drives, the results are the same!
- I tried cleaning the AE cache, no luck
- Turned on and off multiprocessing, no luck

I really do not have the faintest idea what caused this problem... as far as i can tell, the harddrives are fine, the hardwares are fine (I still get very smooth RAM preview), it is not because of the comp (the comp is very simple, also I've tried other comps with no luck). The only thing that I could think of that I haven't tried is reinstalling AE or even Windows... it'd be very unconvenient.

Does anyone have a clue? Please help.


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Nick Hill
Re: Help! Unusual long render time in AE CS3
on Sep 22, 2009 at 12:59:53 pm

have you tried rendering to, say, Photoshop image sequence first, then importing that and rerendering to mpeg2? I find it's better to render to image sequences with anything complex, then if it crashes or hangs you can pick up where it left off.

only other thought is - have you checked task manager > processes? sometimes you might have a process which is eating all the cpu power.

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Tung Bui
Re: Help! Unusual long render time in AE CS3
on Sep 22, 2009 at 2:10:07 pm

Thank you very much for the response.

After I made that post I tried again rendering out the comp to AVI uncompressed (the resulting file was 32 GB), then I ran the AVI file through ProCoder to convert it back to MPEG2 HD format for easier viewing and save space. The whole process took about 20 mins (10 mins render and 10 mins converting) so it's acceptable.

What baffles me is that I have done similar renders before (rendering a .m2v clip with simple text straight to a new .m2v file) and they never took that long (10 mins top for a 4-5 min clip). Maybe someone messed around with AE on my comp or made some changes that caused this. I had Nucleo Pro installed for a while and it was fine until today. I tried uninstalling it but nothing changed so I guess that's not the problem.

Also thanks for the tip about image sequence, it'd be great to be able to resume cus rendering is never totally stable :D

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Dave LaRonde
Re: Help! Unusual long render time in AE CS3
on Sep 22, 2009 at 2:53:03 pm

I'm not surprised at the long render times if it's an m2v file, which is a variety of mpeg2. Read on:

Dave's Stock Answer #1:

If the footage you imported into AE is any kind of the following -- footage in an HDV acquisition codec, MPEG1, MPEG2, mp4, m2t, H.261 or H.264 -- you need to convert it to a different codec.

These kinds of footage use temporal, or interframe compression. They have keyframes at regular intervals, containing complete frame information. However, the frames in between do NOT have complete information. Interframe codecs toss out duplicated information.

In order to maintain peak rendering efficiency, AE needs complete information for each and every frame. But because these kinds of footage contain only partial information, AE freaks out, resulting in a wide variety of problems.


Furthermore, you are doing yourself NO favors by trying to render mpeg2 out of AE. AE doesn't do a good job of compressing to mpeg2. You're much better off rendering a high-quality file out of AE, then using other compression software to do the compression. Apple's Compressor, Adobe Media Encoder and MPEG Streamclip come immediately to mind.

"Oh, but the files are so big!" That's life in AE-Land. Get used to it.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA

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Tung Bui
Re: Help! Unusual long render time in AE CS3
on Oct 31, 2009 at 4:20:58 am

Thank you for the answers.

I have now changed my workflow to render to uncompressed AVI in AE, then encode it back to HDV format for delivery using TMPGEnc. How is TMPGEnc encoding compared to the softwares you have mentioned?

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