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ADDvanced

macrumors regular
Original poster
Nov 8, 2015
147
23
Hi, I have tried posting and asking questions but nobody can tell me the answer, so I am reaching out. This would take someone less than 3 minutes if they alreayd have the hardware.

If you have a 4.1/5.1 with 12 cores, please do the following:

1. Open activity monitor, turn on CPU history
2. Open iMovie
3. Load ANY clip that is 5 minutes long into the timeline, hit CMD+R to enable the time slider, and compress that clip down to 15 seconds.
4. Play it back.

Questions:
1. Does it play back smoothly? Or is it dropping frames/getting choppy? iMovie lacks the ability to 'render' these adjusted files until it exports, and I'm trying to stay with iMovie since all my projects are done in it, and it's simple/fast for me to use.
2. What is going on with the CPU history? Is it utilizing all 12 cores? Or only 6? I have asked everywhere and nobody can tell me if iMovie is multithreaded.

My machine is a 5.1 3.33 hexcore and my iMovie library is on an NVME drive; I thought bandwidth would be the issue for smoother playback of compressed files but obviously that was not it. It is pegging all 6 cores of my machine at 80-90% during playback within iMovie...
 

ADDvanced

macrumors regular
Original poster
Nov 8, 2015
147
23
Kind of doubt it.

I have a 7970, metal compatible, and it's a decent card; if you think about what I'm asking it to do, it's to take a large file (several hundred megs to a gig), and play it back at high speed; which means lots bandwidth accessing the disk, as well as the CPU being able to keep up with the accelerated playback.
 

amstel78

macrumors 6502a
Aug 12, 2018
517
183
Works fine for me. I normally use Davinci Resolve but I took a 10 minute clip I had and compressed it down to about 15 seconds. Played back without any frame drops. I do have H264 and HEVC hardware encoding/decoding enabled at the OS level via OpenCore though, so I do see a lot of the heavy work is being parsed to my Vega 64.

I copied that library and moved it off my PCIe SSD onto a mechanical RAID volume. That's where I start to see the dropped frames. Disk isn't fast enough.
 
Last edited:

ADDvanced

macrumors regular
Original poster
Nov 8, 2015
147
23
Wait, do did you use iMovie or Davinci? A lot of the 'better' editors will 'render' the sped up file and just play that back.
If you did use iMovie:
So in my case, I have a very fast disk (Nvme), but it could be the combination of fewer cores, and possibly my videocard? I am on mojave without opencore... is there still a way to enable hardware decoding/encoding? I'll start googling.
 

amstel78

macrumors 6502a
Aug 12, 2018
517
183
I tested with iMovie.

I use OC to enable HEVC/H264 hardware acceleration. All of that is offloaded to the GPU.

Edit: I also only tested with a 1080p file.
 

ADDvanced

macrumors regular
Original poster
Nov 8, 2015
147
23
Thank you! That's promising. Just have to figure out if 7970 has h264 encoding via opencore but all I'm finding are people arguing about it, lol.
 

amstel78

macrumors 6502a
Aug 12, 2018
517
183
I have a 7950 in my MP3,1. It does not support HEVC or H264 hardware encoding or decoding natively, or via OC. I think you're gonna be out of luck there.
 

ADDvanced

macrumors regular
Original poster
Nov 8, 2015
147
23
Tested iMovie on the dual quad core, it's using all processors, so I pulled the trigger on a pair of x5680s, we'll see what happens. If that doesn't make a noticeable improvement, I'll go from there.
 

amstel78

macrumors 6502a
Aug 12, 2018
517
183
Tested iMovie on the dual quad core, it's using all processors, so I pulled the trigger on a pair of x5680s, we'll see what happens. If that doesn't make a noticeable improvement, I'll go from there.
I have two X5690's in my MP5,1. The bottleneck is going to be the data bus between processor and storage media as well as GPU. I doubt you'll see too much of a difference with 2 X5680s without a better GPU and an OS to support it.

I can process 4K video fairly well with my current config, Resolve 17, and Mac OS spoofed to allow H264 and HEVC hardware support. But to be completely honest, I'd rather be doing video work on my Windows 10 box with an AMD Threadripper and 1080TI. I'm only using my older Macs because I relocated to my summer home after NYC went BSC last March. Unfortunately my main video machine is at my apartment there.

Put it this way: I've had to stop filming drone footage in 4K while I was here just to make my workflow faster on the MP5,1.
 
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eicca

Suspended
Oct 23, 2014
1,773
3,600
You'll definitely want to enable hardware acceleration through OpenCore. Before I did that, my Final Cut was just laggy all over the place and took over two hours to render a 15-minute 1080p video. Once I enabled GPU hardware acceleration it was much smoother and rendered the 1080p video file in 5 minutes.
 
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ADDvanced

macrumors regular
Original poster
Nov 8, 2015
147
23
Luckily I don't mess with 4k, and yeah windows is fast/cheap but I seriously just like using iMovie. I can use premiere and FCP but there's so many options and I get caught up tweaking stuff so much that it just takes me longer to do anything. iMovie is just quick/simple, poop out a video.
 

eicca

Suspended
Oct 23, 2014
1,773
3,600
This thread is the safest way to implement OpenCore. It'll do it without touching your primary drive, and if you have a problem it's extremely easy to undo.
 
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