4K Playback stutter on Mac Pro late 2013

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Level 1

35 points

4K Playback stutter on Mac Pro late 2013

Hi,

I have a mac pro late 2013. 3.5ghz 6 core with 64 gig of ram and AMD FirePro D500 3072MB - not sure if that's dual cards or one card that takes two slots. I have two displays attached, one is an Eizo 30" SX3031W and the other is a Samsung 47.5" 4K TV via HDMI.

I record 4K on a Sony A7R Mk II and if I play that video back directly from the camera to the Samsung 4K TV over HDMI, the video plays perfectly. But if I import the video file (drag and drop to built in SSD, no transcoding) from the camera to the Mac and try to play it on either monitor using Quicktime or VLC, it stutters. Similarly if I import the file into FCP it stutters, and if I then export it with compressor, it stutters.

I am really scratching my head: I purchased this machine in order to do this sort of work but only recently got the 4K capable shooting gear and just assumed that with this spec it would work.

Any ideas?

Mac Pro, OS X Mavericks (10.9.2)

Posted on Aug 19, 2015 4:26 AM

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Answer 1

Oct 30, 2015 5:19 AM in response to shmuleyhoffman

Rather than Thunderbolt vs HDMI, I believe the issue may be slightly different.

The Mac Pro has 3 Thunderbolt buses, and the HDMI port is in fact in Thunderbolt bus 0 (along with the two lower TB ports).

The two top ports on the left are on bus 1, and the two top on the right are on bus 2.

I bet that as long as you connect your two displays on separate buses, you'll be all right.

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Answer 2

fox_m

Level 6

13,282 points

Aug 20, 2015 2:12 AM in response to Tim Ashley

Sorry to hear that! Have you Optimized the footage in FCPX? ... and if you need to optimize, have you updated the ProRes codecs? There were supposed to be a lot of improvements regarding XAVC in the last 6 months or so.

XRef: Import Sony XAVC and XDCAM media in Final Cut Pro X - Apple Support

and Pro Video Formats 2.0.1

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Answer 3

Aug 21, 2015 3:01 AM in response to Tim Ashley

Tim Ashley wrote:

Thanks for the suggestions but I'm afraid those possibilities don't apply; I have only one monitor plugged in via thunderbolt, the other is via HDMI.

The HDMI port also on Thunderbolt bus 0.

See here:

Mac Pro (Late 2013): Using multiple displays - Apple Support

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Answer 4

Russ H

Level 7

22,432 points

Aug 19, 2015 8:38 AM in response to Tim Ashley

That is surprising. From what I've heard, it should work well without transcoding.

Three thoughts: 1) run the Apple Diagnostics and DU Verify Disk to see whether any hardware issues are reported. Then do a Safe Boot. Log in and restart; 2) In FCP Viewer Options, Quality, choose Better Performance to see what difference that makes (although that doesn't explain why the clips don't play right on VLC); 3) disconnect one of the displays and test playback.

Russ

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Answer 5

Tim Ashley Author

Level 1

35 points

Aug 19, 2015 11:27 AM in response to Russ H

Thanks for the suggestions Russ, all tried, nothing really works: the HDMI>4K tv works better when it is the only connected monitor but it still stutters. The file is running at 84 mbits/s. It isn't really possible to to see how well it is playing when the regular computer monitor is connected because there's automatic downscaling going on for the lower resolution.

I've even tried loading the file onto an SDXC card and playing it directly to the TV via a USB3 card reader and the TVs inbuilt media player. That works perfectly.

There's something wrong with the Mac and actually the more I search the more I see that plenty of other people have had similar problems but so far Apple hasn't acknowledged it or done anything about it, as **** as I can discover...

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Answer 6

Aug 19, 2015 11:53 AM in response to Tim Ashley

Stuttering is typically a hard drive issue but that SSD should be plenty fast enough.

Check out this web page on which ports to plug your Thunderbolt 2 devices in:

http://www.tekrevue.com/tip/mac-pro-thunderbolt-performance/

That Mac has 3 Thunderbolt busses. You want to plug each monitor into a different bus.

Have you tried unplugging the 4K TV from the HDMI port to see how it performs in FCP X? You want to set the display pane to Performance instead of Best Quality.

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Answer 7

Tim Ashley Author

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35 points

Aug 19, 2015 1:54 PM in response to Scot Walker

Thanks for the suggestions but I'm afraid those possibilities don't apply; I have only one monitor plugged in via thunderbolt, the other is via HDMI. I've tried all other possibilities and permutations, isolated each monitor, fiddled with settings in FCP etc but please note, this is not just in FCP: it is also in Quicktime and VLC.

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Answer 8

Tim Ashley Author

Level 1

35 points

Aug 20, 2015 1:20 AM in response to fox_m

It's far less than half full. I think this is likely a general problem with Late 2013 Mac Pro and HDMI/4K sadly - there are plenty of other reports of people with stuttering video. It seems a number of people who rely on high-end macs for their livelihood are sorely disappointed....

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Answer 9

Tim Ashley Author

Level 1

35 points

Aug 20, 2015 2:53 AM in response to fox_m

The stuttering occurs on any footage, whether optimised or simply dragged and dropped form the camera's SD card and whether played through QT or anything else and whether located on the internal SSD or an external RAID. As for updating ProRes codecs, I assume, possibly incorrectly, that this would be achieved any time I update FCP?

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Answer 10

Oct 29, 2015 4:55 PM in response to Tim Ashley

Ok guys. I found the problem. Went to apple store checked their latest iMacs with my project that stuttered like heck in 4k. Couldn't find out why my Sony 4k footage wouldn't play smoothly on my Mac Pro 2013.

Here is what you need to do:

If you work on 2 monitors as I do we usually put both monitors on thunderbolt, right? Thats where the hick up starts to happen. The only way of playing 4k footage with two monitors WITHOUT a seperate i/o set up is that your working monitor needs to be hooked up to thunderbolt. Meaning to say the one where you display the timeline of FCPX. Your control monitor the one where you display the viewer of FCPX NEEDS TO BE HOOKED UP VIA HDMI ONLY!!!

If you do this then you get smooth playback and the Mac Pro together with FCPX is like a beast again. If you put them both on thunderbolt they work like a macbook Air.

Hope this helps and I wonder that even at apple store genius they couldn't tell me that.

I fished the info from the apple website and deciphered their lingo.

Shmuley

EntreFilmmaker.com

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Answer 11

Oct 30, 2015 5:38 AM in response to Luis Sequeira1

I have a 4K monitor and a thunderbolt monitor connected to 2 different TB busses as described above. I edit 5K native RED footage just fine. It plays back in real time at 100% on the secondary monitor (the 4K) and my timeline and UI is on my Thunderbolt Display.

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Answer 12

Tim Ashley Author

Level 1

35 points

Aug 19, 2015 4:31 AM in response to Tim Ashley

BTW OS is 10.10.3

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Answer 13

fox_m

Level 6

13,282 points

Aug 19, 2015 9:02 PM in response to Tim Ashley

How "full" is your SSD? The OS needs at least 10% headroom of every disk for various system operations (like paging, etc.) If your disk is almost full, that can slow everything down, SSD or not.

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Answer 14

fox_m

Level 6

13,282 points

Aug 21, 2015 10:34 AM in response to Tim Ashley

There have been several (perhaps all) ProRes updates that have been separate downloads from the FCPX updates. They're not just for FCPX.

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