Fully Loaded imac dropping frames during multicam editing (Using proxies)

I am editing a music video and I have 6 different angles I put them all into a multicam clip and whenever I open angle viewer fcpx starts to drap frames during play back. I even have it set to use proxys to prevent lagging so I don't know what else to do...Any ideas?

I have a brand new fully load imac so I don't know what it is dropping frames

-27" iMac (5K Retina, late 2015)
-OSX 10.11.5 (El Capitan)
-4 GHz Intel Core i7
-3TB Fusion Drive
-32 GB RAM (4 8GB 1600 MHz DDR3 modules)
-Graphics Card: AMD Radeon R9 M395X 4096 MB

Is your media on the Fusion drive? It needs to be on a fast external drive. Fusion is not good for video.

I have a Lacie d2
3 TB
7200RPM HDD
Connected via Thunderbolt 2

Write speed 199 MB/s
Read speed 207 MB/s

...Will that work better than my built in fusion drive to fix my issue?

Yes.

ok thanks! so is that my only option towards fixing this problem?

Probably.

You probably already tried to set the playback to "performance" instead of "quality"?!

nils.dettmann wrote: You probably already tried to set the playback to "performance" instead of "quality"?!

Yes I already tried that, In fact when you switch to proxy it doesn't even allow you to choose better performance or quality because proxy is automatically lower quality but better performance

mgmartino wrote: I am editing a music video and I have 6 different angles...

Is this 1080p or 4k?

mgmartino wrote: I have a Lacie d2
…
Write speed 199 MB/s
Read speed 207 MB/s
…

This is a superb drive - but imagine, what's going on, when you use it for Multicam:
For a MC, FCPX demands all streams simultanously.
So, poor read/write-head inside that box, has to quiver between six different places on the platter, search it, find it, lock to it, change track, and again.....

I'm using a near-specs-bottom setup (MacMini, i5, 16GB) - but several mechanical drives = no stutter.

1080p

joema wrote:

mgmartino wrote: I am editing a music video and I have 6 different angles...

Is this 1080p or 4k?

1080p

Karsten Schlüter wrote:

mgmartino wrote: I have a Lacie d2
…
Write speed 199 MB/s
Read speed 207 MB/s
…

This is a superb drive - but imagine, what's going on, when you use it for Multicam:
For a MC, FCPX demands all streams simultanously.
So, poor read/write-head inside that box, has to quiver between six different places on the platter, search it, find it, lock to it, change track, and again.....

I'm using a near-specs-bottom setup (MacMini, i5, 16GB) - but several mechanical drives = no stutter.

I might not be understanding the terminology of "mechanical drivers" but how is your computer able to run a 6 angle multicam clip with no stutter with much lower specs than mine?

mgmartino wrote: ...
I might not be understanding the terminology of "mechanical drivers" but how is your computer able to run a 6 angle multicam clip with no stutter with much lower specs than mine?

sorry, 'drives' .... ok, that superflouos 'r' made my reply completey undecipherable ...

read again my description what your single mechanical drive has to accomplish.
now, spread your 6 sources onto 6 individual platters (just in case: means 'drives') - ... = my method.

And 'mechanical', 'cause a hdd utilizes basically the same techniqué as a record player from 1920. Unlike SSDs, I'm using too two ext. SSD as media-drives.

(although double-checked, text can contain spells&grammars)

So with multicam shoots you are putting every angle on a different drive?
Interesting concept but some more organisational work.

I hope this isn´t two far OT but it´s interesting how every article, test and review is concentrating on the throughput of storage and rarely talks about seek times.

nils.dettmann wrote: So with multicam shoots you are putting every angle on a different drive?
Interesting concept but some more organisational work....

hmm, not really, depends on the formats in use:
I have to transfer from cam/card anyhow, then in FCPX 'leave files in place'. That easy.
me lazy to search myself:
you'll find an older post of mine "4k 4xMulticam on Macmini"… no real use, more a stunt, but fun to show APr on Windows users... :evil:

As mentioned, I'm on a very low spec system (and an even lower budget, it's hobby!).
I'm less interested in abstract speed-tests, prefer the 'real life' numbers. (such as BruceX)

And my 70€ platters don't deliver that fast, not speaking of the connection speed, but 'from platter to screen'

BM Diskspeed tells me ~70mbps for my 2.5" drives, ~120mbps for my software raid0, and ~420mbps for my ext.SSDs => without limiting mechanics, my method of 'MultiCam/MultiDrives' isn't needed anymore.

btw: I use a diff. drive for exports too ... same story here, intHDD is for OS&app, cache, sources and export on separte media.

On a lame Mac like mine, smart media management gives noticeable improvements... :woohoo:

mgmartino wrote: ...I might not be understanding the terminology of "mechanical drivers" but how is your computer able to run a 6 angle multicam clip with no stutter with much lower specs than mine?

As Karsten said, speed degrades a lot due to conflicting concurrent I/O streams. You have six streams of 1080p proxy media, which are each 1/2 the linear resolution and 1/4 the total resolution per frame of the original content. So instead of H264 frames of 1920 x 1080, each frame is lower-compression ProRes at 960 x 540.

Combining the lower proxy resolution with the lower compression ProRes encoding, this produces files very roughly 1/2 the size, which equates to roughly 1/2 the I/O rate of the original files.

An additional major savings is lower CPU burden from not decoding the highly compressed H264 format, even though your Mac does have Quick Sync decoding assistance. So using proxy vs H264 reduces both I/O load and CPU load, which is why it's so advantageous.

If you have ever copied a group of files between hard drives, it is obvious it's faster to do them sequentially than in parallel. Copying six files in parallel will be far slower than doing them in sequence, because the HDD must rapidly seek between each one. There may also be adverse buffering issues, or "cache thrashing" on both drive level and by the file system buffer. This can cause a drastic exponential degradation in I/O performance.

A six-angle multicam is essentially copying six files at once. Having all that content on a system boot drive (even if Fusion) will probably not yield good performance. They need to be on a fast external drive, series of drives or RAID array capable of supporting that I/O rate.

Note if your media is on an external drive but the library (containing your proxy files) is on your boot drive, it will do most of the I/O to the library so having the external drive will not benefit greatly. You can move the library to the external drive.

People sometimes overstate the importance of I/O, as if that will solve anything. However this is likely not one of those cases. With large multicam projects, I/O is very important, and more than aggregate transfer rate is needed -- I/O operations per second in a random seek workload is important.

I have a much less robust system than you and I do 4-6 angles of 4K in proxy on a regular basis with no real performance issues. I don't know what the problem is, but you shouldn't be having any trouble. I edit off of G-Tech portable USB-3 7200rpm drives, so the throughput on the thunderbolt should be faster than what I have. Maybe the drive is faulty or there is some bad hardware or a bug involved. But there is no reason that you should have that problem with your setup. Maybe try a different external, and if the problem persists contact Apple.

Another possible issue is effects. If he has a significant number of effects applied, especially computationally-intensive ones, this can slow down almost any computer.

One way to test this is fully render the timeline of the multicam project, then try to scrub forward and backward in the timeline. If it is fast then but slow with an unrendered timeline, the problem may be the CPU/GPU load, not I/O.

I thought we were talking about frame drops in the multicam editor when all angles have to be streamed in parallel.

One factor is also the datarate of the sources at least in non-proxy-mode.