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chris walker
extremely slow export
on Apr 2, 2017 at 11:54:27 am

i have fcpx 10.2.1, 8 gigs of ram, 2011 imac, osx 10.10.5. i have an 80 minute 1080p timeline using 4k footage from panasonic g85 and gx85. exporting to prores rather than h264 so i can get better downscaling for dvd. i have done this many times before, using hd footage rather than 4k, and the speed was always reasonable. but this time its extremely slow; its at 2% after 20 minutes. discs have a lot of space, no other programs running. i tried deleting render files and trashing preferences. should it be this slow, just because its 4k? i edite using proxy files, but was careful to change the view ro optized/original before exporting. please help! i cant have the computer tied up for days just to export a file..


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Noah Kadner
Re: extremely slow export
on Apr 2, 2017 at 2:15:58 pm
Last Edited By Noah Kadner on Apr 2, 2017 at 2:16:16 pm

Unfortunately that sounds about correct for those system specs and formats.

Noah

FCPWORKS - FCPX Workflow
FCP Exchange - FCPX Workshops
XinTwo - FCPX Training


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Joe Marler
Re: extremely slow export
on Apr 2, 2017 at 11:43:20 pm

[chris walker] "fcpx 10.2.1, 8 gigs of ram, 2011 imac, osx 10.10.5...80 minute 1080p timeline using 4k footage from panasonic g85 and gx85. exporting to prores rather than h264...i have done this many times before, using hd footage rather than 4k, and the speed was always reasonable. but this time its extremely slow; its at 2% after 20 minutes...should it be this slow, just because its 4k? "

FCPX won't export 4k from a 1080p timeline, so I don't understand that part. However your performance seems very slow. OTOH 4k is 4x the data of 1080p, so if by "always reasonable" before, you mean it was 4x faster when exporting to 1080p, that would make sense. I did several timed export tests of 4k Panasonic H264 content using a top-spec 2015 iMac 27 and FCPX 10.3.2. I then compared this to export time of 1080p H264 material from a 5D Mark III and lastly the export time of H264 4k from Premiere Pro CC 2017.0.2.

The only Panasonic camera I have lots of footage from is the DVX200. I did the following export tests using 30 minutes of 100 mbps UHD 4k H264 material, so you'll need to multiply by 2.66x to equal your 80 min timeline. Note there are three possible resolutions in play (1) resolution of original material (2) resolution of timeline (3) resolution of export.

Export 30 min. 4k H264 from 4k timeline to 4k H264: 21:00
Export 30 min. 4k H264 from 4k timeline to 4k ProRes 422: 21:00
Export 30 min. 4k H264 from 1080p timeline to 1080p H264: 9:18
Export 30 min. 4k H264 from 1080p timeline to 1080p ProRes 422: 12:14 (repeated twice to check)

1080p Export Tests from Canon 5D Mark III using 30 mbps IPB H264 codec:

Export 30 min. 1080p H264 from 1080p timeline to 1080p H264: 5:39
Export 30 min. 1080p H264 from 1080p timeline to 10800 ProRes 422: 5:12

Export test from Premiere Pro CC 2017:

Export 10 min. 4k H264 from 4k timeline to 4k H264 at same output bitrate as FCPX: 26:47 (Premiere is 3.8x slower than FCPX on this test)


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chris walker
Re: extremely slow export
on Apr 3, 2017 at 2:02:16 am

Hi,

I should have made clear that the original footage is 4k but the timeline is 1080p. I'm exporting to prores 1080p, which is a file thats about 100gb in size. This is so when I reduce it down to sd in a separate step to make a dvd, the downscaling looks better. Ive used this workflow a lot with 1080p original footage, and if I export to a 100gb prores file it takes up to several hours. I figured that with 4k footage reduced down on a 108p timeline, it might take several hours more because the 4k has to be transcoded first, but instead its taking much longer than that. Now Im 60% done after 18 hours.

If it is simply that with my relatively old computer and small amount of memory it is typical for it to take this long, I feel like Ive been mislead. Because when I researched this when I was deciding whether to switch to a 4k-to-1080p workflow for better quality, I read articles about how you could even do this on a laptop if you used proxy files, and indeed, the editing process has turned out to be easy when working with these smaller proxy files. But the articles didnt say anything about it taking forever to export the 1080p prores file. Perhaps they were assuming that the export would be to h264, which is a much smaller file size.

So if it is the case that i simply need a faster computer and/or more memory, I'm wondering what workarounds there are. For example, as I get closer to finishing a project, could I periodically switch the view to original/optimized and select a ten-minute section to render overnight? I've noticed that when, in order to check what the final version is going to look like, I do a render of a short section, say 30 seconds, with the view option on original/proxy, that takes quite a long time, so maybe it is transcoding at that point. So if I did these periodic renders, would that mean most of the transcoding would already be done when the time came to export, making the exporting a lot quicker? I will do some tests to see, but does anyone know if that would work? I really dont want to get a new computer if i dont have to..


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Noah Kadner
Re: extremely slow export
on Apr 3, 2017 at 6:40:57 am

Faster computer and/or a camera shooting 4K straight to ProRes. Or an outboard HDMI recorder.

Noah

FCPWORKS - FCPX Workflow
FCP Exchange - FCPX Workshops
XinTwo - FCPX Training


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Joe Marler
Re: extremely slow export
on Apr 3, 2017 at 11:30:20 am

[chris walker] "....the original footage is 4k but the timeline is 1080p. I'm exporting to prores 1080p...so when I reduce it down to sd in a separate step to make a dvd, the downscaling looks better. Ive used this workflow a lot with 1080p original footage, and if I export to a 100gb prores file it takes up to several hours. I figured that with 4k footage reduced down on a 108p timeline, it might take several hours more because the 4k has to be transcoded first, but instead its taking much longer than that. Now Im 60% done after 18 hours...If it is simply that with my relatively old computer and small amount of memory it is typical for it to take this long, I feel like Ive been mislead...I'm wondering what workarounds there are....I really dont want to get a new computer if i dont have to.."

You're saying it takes much longer to export 1080p from a 4k file than from a 1080p file. That is correct -- just because the timeline is 1080p doesn't alter this. The timeline is only for intermediate renders. When you need to generate the final output it must go back and process the original 4k file. If it did not do that, you could not zoom in on content using the original 4k resolution.

On my 2015 iMac 27 it takes roughly 2.4x longer to export 1080p ProRes from a 4k H264 source than a 1080p source. This should not be surprising -- it is 4x the data. If it were 4k output it would be about 4x longer. Exporting to 1080p saves some time, but taking 2.4x longer is expected. This is not unique to FCPX. Premiere Pro CC 2017 running on the same hardware takes 2.3x longer to export to 1080p H264 from a 4k H264 file than from a 1080p file, plus the overall time is 3.8x slower than FCPX.

On my iMac it was a bit faster to export from an H264 source to H264 output than ProRes. You could test this on a small file and see if it applies to yours. Are you certain that a 1080p ProRes file will look better than H264 if downscaled to DVD? Did you actually test this and inspect it, or are you just assuming it might be better? If you test it and can't tell any difference, you could save some time that way.

Handling large amounts of 4k H264 is one of the most difficult things a computer can do -- regardless of what editing software. It can be challenging on a top-spec 2015 iMac 27 or even a Mac Pro. Proxy enables the edit phase to work faster, but when you do the final export, that original 4k content must be processed -- if you want the benefit of 4k. If you don't want that benefit you could shoot in 1080p or externally transcode the 4k to 1080p before importing it.


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