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18 HOUR RENDER TIME!!!! Is that normal?

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Jenessa Kenway
18 HOUR RENDER TIME!!!! Is that normal?
on May 30, 2013 at 1:48:00 am

Hi all,

What is a normal amount of time for a high quality export out of FCP 7? I usually work with PremierPro but chose to assemble Mp4 clips created in Premiere in FCP for my final video output. The clips imported and after an initial 6 hour render played without a hitch. The initial render seemed inordinately long time but was successful. I am new to working with HD footage and quickly discovered things often take quite a bit of time to render.

Now I'm ready to export a 20 minute mp4 video out of FCP 1080pHD 29.96 frame rate. After researching appropriate export settings, I chose: MP4, H.264, Data Rate 650. I realize HD footage takes longer but I'm faced with 18 hours and wondering for an export is this normal? or is something potentially really wrong? I've never encountered an export time this lengthy before.

I'm working on a:
2009 iMac OSX 10.8.3 Intel Core 2 Duo
8GB Ram
316 free gb's of space.

Thanks for any help, comments or suggestions.


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Ben Rojas
Re: 18 HOUR RENDER TIME!!!! Is that normal?
on May 30, 2013 at 2:38:38 am

I'm amazed the MP4 files are working at all. Normally anything heavily compressed, like Mp4's, should be transcoded to ProRes, Uncompressed or something less taxing on the system. You're scratching your head right now... "but Premier has no issues with... ", correct, but it's also not legacy software ;o) At this point, what you can do to not wait the 18 hours, export the timeline at whatever format your sequence is at... Once you've got that file, create your deliverable in Media Encoder. I don't use Compressor anymore as I find Media Encoder to be better and faster. Good luck.

Ben Rojas
Editor | Producer

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Shane Ross
Re: 18 HOUR RENDER TIME!!!! Is that normal?
on May 30, 2013 at 4:30:35 am

FCP doesn't work like Premiere. Premiere works with formats natively, FCP does not. FCP likes footage to be ProRes if it is HD. It doesn't work well with MP4 or you can see. You can't approach working in FCP like you do premiere...they are different beasts.

As stated, you need to convert the footage to ProRes before you bring it into FCP. Otherwise you are stuck rendering, like you did. 6 hour render times is long, because you did things wrong.

Might have been easier to stick with premiere from start to finish. WHy did you go to FCP?

Little Frog Post
Read my blog, Little Frog in High Def

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Jenessa Kenway
Re: 18 HOUR RENDER TIME!!!! Is that normal?
on May 30, 2013 at 3:35:27 pm

Hi Shane,

Thanks for the advice. It should have occurred to me that rendering footage that has already been compressed and formatted by another program would have problems and crappy pixelated results.

I would prefer to just complete the project in Premiere. (I'm working with the CS4 version) The reason I hopped into FCP is because I'm having difficulty exporting completed projects from premiere. It works ok with rendering short HD clips but when I try to export the entire 23minute project the export crashes giving me the "unknown error compiling movie" message. I looked deeper into the error message and it said something about "source duration time out" and "insufficient source duration." I interpreted this initially as it didn't like writing the export to the external hard drive but when I switched to the regular hard drive the same thing happened again so I'm not sure what to think. I'd love to hear any ideas as to what might be causing this crash and suggestions for fixing it.

Thanks again!


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Joseph Owens
Re: 18 HOUR RENDER TIME!!!! Is that normal?
on May 30, 2013 at 4:09:28 pm

When you are advised to recompress your H264/mp4 type footage to a format like ProRes, what you are really being asked to do is convert your footage from a "Long-GOP" (Group-of-Pictures) format to an "intra" format.

What this means is that the editing application really wants to deal with a stream of data that is composed of discrete frames -- that is an actual 29.97 frames per second (if that's the format you're working in) rather than the extremely highly compressed GOP strategy of providing 2 whole frames per second with the rest being "difference" predictive and bi-directional data, and that is your MP4-type codec. This also applies to formats like HDV, and is made even more complicated when the camera is producing 24 fps material, but being recorded to 29.97 Long-GOP. Its a nightmare.

The editing software has to create the discrete frames "on-the-fly" when you are trying to work with a GOP format. FCP never really got the hang of it, although what does exist almost works well enough to lull an operator into believing it will work. Another triumph of engineering over common sense. But when the shoe drops at the end of the day, it is time to pay the piper. Creating a low-bitrate MP4 from an HD ProRes timeline takes quite a while by itself, but the double expansion/compression of coming from a long-GOP source, edited on an intra timeline and then recompressed back, with the ibp re-ordering that is involved, is guaranteed to stack up the render big time. Even exporting a 1080P23.98 ProRes 42 minute show will take 14-16 hours if you want it converted to interlaced 29.97. I have seen the same project take up to 26 hours to yield a streaming H.264.


"I always pass on free advice -- its never of any use to me" Oscar Wilde.

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