5k imac video editing advice sought.

Discussion in 'iMac' started by Squirkytunkle, Dec 1, 2014.

  1. Squirkytunkle macrumors member

    Dec 1, 2014

    I'm new to this forum. I've been trying to find users on the net with experience with editing 4k video footage, or editing magic lantern hacked raw 5d iii video on the-new imac. I know a Mac Pro is going to be the obvious choice here, but still, I'd be very curious to hear some real world results from users who have done so. I can find very little info in this area.

    I work primarily as a photographer and sound designer and for these my 2009 i7 imac is still going good for my needs. Recently however, I've begun to blend my sound and visuals with experiential time lapse work and doing the odd bit of video.

    Working with the latter is why I need to upgrade now, but as I'm not sure how much video work I'll end up doing, I don't want to go with a Mac Pro if I can get away going with the 5k imac (maxed out) I would like to use the Magic Lantern hack on my 5d iii for video work or maybe shoot 4k next year for whatever video work I'll be doing. This May or may not end up been quite little- I would be happy to work with proxies in FCPX and I'll be adding a RAID 5 setup soon. My videos will be all under 10 minutes max. I do however seem to work with three or four layers at a time.

    Would I better off looking at a 6 core Mac Pro (the most I could afford).

    Any help is much appreciated.
  2. yjchua95 macrumors 604

    Apr 23, 2011
    GVA, KUL, MEL (current), ZQN
    If you're not using it for full-time video editing, the 5K iMac will do you fine.

    I've got a 5K with 4GHz i7, 32GB RAM, 512GB SSD and 4GB R9 M295X, and it's pretty smooth in 4K video editing. The fans will whir up softly though, but that's about it.

    I shoot 4K footage with a EOS-1Dc.
  3. Squirkytunkle thread starter macrumors member

    Dec 1, 2014
    That's great to know. Thanks most kindly for the reply.
  4. fathergll macrumors 65816

    Sep 3, 2014
    I think generally performance isn't too much of a concern with the new iMacs its more to do with if you're doing a lot of heavy lifting on it with video..etc then heat could be a concern.
  5. Squirkytunkle thread starter macrumors member

    Dec 1, 2014
    Yeah, that's something i'm kind of wondering about. As i might be blending two to three layers of video at a time, then maybe that could be deemed as a bit on the heavy lifting side. As a might end up doing little video however, then maybe i might be fine with the iMac. I'm just not sure where i'm going with video as yet, or whether i'll end up doing much of it at all. I'm still doing far far more photography and sound work at the moment.

    Thanks very much for the reply. I'll be keeping this in mind.
  6. joema2 macrumors 65816


    Sep 3, 2013
    I shoot and edit lots of 5D3 1080p video on my top-spec 2013 iMac. It works fine. I've edited some 4k H.264 material from a Lumix GH4 which also works, although it's about 3x the data rate.

    As you know Magic Lantern raw video is totally different and a vastly higher data rate. I have not tried that because I do documentary and event work and cannot risk it in the field, esp. with the storage requirements. 1080p raw is about 90 megabytes/sec, so a 32GB CF card would last about 5 min.

    If your final product is 10 min and if your shooting ratio is only 10:1 (low by today's standards) your total raw footage would be about 540GB, really not that bad.

    5D3 raw video via ML is very impressive, and if you're shooting scripted narrative, can afford multiple takes, and a more complex post-production workflow, maybe it's OK. If you're shooting event/documentary work, it's not as good a fit.

    In general if you want 4k I'd recommend a 4k camera like the GH4.

    I do lots of time lapse work from either DSLR or GoPro material and it works fine on the iMac using FCP X and Quicktime 7 Pro. Technique is discussed here: https://www.youtube.com/watch?v=2kgN5mJaHy0

    I use an 8TB Promise Pegasus R4 Thunderbolt. It works fine but there are other options such as the OWC Thunderbay 4 and SoftRAID.

    The dilemma is a 4Ghz top-spec retina iMac is about as fast on many things and faster on others. The iMac is vastly faster on single-pass H.264 rendering using FCP X or Handbrake since the CPU has Intel's Quick Sync on-chip transcoder.

    It's good to think about total system and total budget. You must examine what you can buy for x dollars. If you will need a RAID5 array and other HDDs to back that up, that adds to the total budget. If you'll need a 4k monitor and don't have one, that adds to the total budget, etc.
  7. marvguitar macrumors member

    Mar 12, 2011
    I edited a R3D project this weekend in PPcc2014 and colored with Resolve and it was smooth butter using a single G-RAID drive (Non-ssd)

    I edited / colored at 1/4th and rendered PR422HQ 4K - Playback is smooth at 4K as well and looks stunning on the New Retina iMac.

    My specs: 4.0Ghz / 32GB / 295X

    I also did some de-noising in AE and simple VFX at 4K and was very surprised how fast AE rendered at 4K.

    You can do amazing things with this computer and it won't slow you down.
  8. Squirkytunkle thread starter macrumors member

    Dec 1, 2014
    Thanks for that.

    I have no doubt that if i stick with video, i'll be looking at a camera capable of shooting 4k at some point. I'm not going to use the Magic Lantern hack till it is out of bleeding edge- i'm not that adventurous a person even if it is unlikely to cause any problems.

    For me shooting RAW video isn't much of an issue as i'm creating work for myself as an experimental artist rather than working for clients with deadlines to meet.

    Yeah i'm pretty sure i'm going to go with the Thunderbay with software RAID 5 for my setup. I think when i look at it from the way you mention taking 4k monitors into account and such along with RAID enclosures and drives to back that up, the Mac Pro seems more financially unmanageable.

    Thanks for the reply.


    Now that's the kind of reply i was hoping to hear. That definitely makes me strongly consider the 5k iMac.

    Thanks very much.
  9. Ski13 macrumors newbie

    Dec 3, 2014
    marvguitar, how has Resolve preformed on the Imac. I do a lot of editing (Avid) and a good deal of grading in Resolve, and whilst I have little worry for the editing performance I do however worry that the GPU will run out of memory very quickly doing some mildly complicated grades. Have you run into this?

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