Export segmentation is a new feature in Final Cut Pro 10.7 that becomes available when you upgrade to macOS Sonoma.
Export segmentation accelerates H.264 and HEVC compression in Final Cut or Compressor by splitting export files across multiple media engines in supported Apple silicon SoCs. (This feature doesn’t affect ProRes exports.)
NOTE: Supported chips are the M1 Max & Ultra, M2 Max & Ultra and M3 Max.
I tested this new feature and discovered that, while it does make exports faster, it also has other benefits – and limitations.
EXECUTIVE SUMMARY
Export segmentation does speed exports, but less than I expected. For example, it reduced encoding times in Compressor an average of 14%. While this feature works in both Final Cut and Compressor, it is better in Compressor. For example, when compared to exporting the same file in Final Cut, Compressor was about 25% faster.
NOTE: Part of this speed difference may be that projects were unrendered in FCP, while Compressor was compressing finished movies.
There are limitations to using Export Segmentation in Final Cut, the biggest is that, while Apple’s Help files indicate this feature supports using File > Share > Export Media, I could not get this to work. This limitation means there are restrictions on export frame sizes in FCP.
A pleasant surprise, though, was that when Export Segmentation was turned on, compressed file size was reduced an average of 27% when using default settings in Compressor.
My recommendation is to use Export Segmentation in Compressor, rather than Final Cut. For maximum performance, though, be sure to also enable additional Compressor instances in Compressor as well as Export Segmentation.
THE TEST SYSTEM
I ran these tests on an M2 Max Mac Studio with 64 GB of RAM, running macOS Sonoma 14.2.
My FCP test files were four Final Cut projects ranging in length from seven to 35 minutes. I used ProRes 4444 exports of these projects for my tests in Compressor. All these projects/files had a non-standard frame size of 1600 x 900, which I use for my webinars, at 30 frames per second. All projects were unrendered.
I first tested the speed of exporting a single file – the 35 minute project. Then, I exported the three shorter files as a group. The results were similar for both the single file and the group.
FINAL CUT PRO
According to the Help files, Final Cut is supposed to support export segmentation when using File > Share > Export Media. However, as this screen shot illustrates, I could not get it to activate; not for a selected project in the Browser or timeline, nor in Preferences > Destinations.
This is important because this is the only export option in Final Cut which supports non-standard frame sizes.
I could enable export segmentation when exporting using the Share setting for Apple Devices 720p or 1080p, but that forced a frame size change to the project. While export segmentation was 10% faster in Final Cut when it was enabled, this speed improvement was not worth resizing the project.
NOTE: If all your projects are 720, 1080 or UHD in size, this limitation does not apply.
Another “problem” with using export segmentation in Final Cut is that it creates a compressed master file. Seeing as we often need to create multiple compressed versions of the same master file for different distribution outlets, this means that we constantly need to go back into Final Cut to re-export the media.
A MUCH! better and, ultimately, faster way to work is to export a ProRes master file from Final Cut, then compress it using export segmentation in Compressor. The benefits to this workflow are:
COMPRESSOR SETUP
Depending upon the chip inside your computer, Compressor supports running multiple Compressor instances. (This feature applies to both Apple silicon and Intel systems.)
This means that if you are compressing multiple files at the same time, Compressor will compress them in parallel, thus saving time. This is illustrated in the screen shot above where all three files are being encoded at the same time.
To enable this, open Compressor, then go to Compressor > Settings > Advanced and click the “Enable” checkbox. (It is off by default.) I recommend setting the number of instances to the maximum, which varies by chip.
NOTE: If performance degrades too much, lower the number of instances.
To enable export segmentation, select a compression setting applied to a clip or in the Custom Settings panel.
Go to Inspector > General and make sure both Allow export segmentation and Optimize for Network Use are checked. (Optimize is generally off by default.)
NOTE: You can’t change these settings for a default compression setting, but they can be changed for custom compression settings or any setting applied to a clip.
Finally, click the Inspector > Video text button in the Inspector, scroll down near the bottom and uncheck Multi-pass. (It is enabled by default.) If this is checked, it disables hardware acceleration which is the exact opposite of what we want to do here.
THE RESULTS
When I apply the default Social Platform > HD 1080p setting to my test files, which supports variable frame sizes, encoding times are reduced 10-16%, while still preserving the non-standard frame size.
What’s MORE impressive is that compressed file sizes are, on average, 26% smaller when using a default compression setting and export segmentation is enabled. When I apply one of my custom settings, which are tuned for small file size, compressed files are still smaller by about 1%.
SIDE NOTE ON SYSTEM RESOURCES
(Click to view larger image.)
The reason for the speed increase is that FCP/Compressor offloads the encoding to additional media engines which are a separate section of the Apple silicon SoC.
Notice in this screen shot that:
SUMMARY
Export segmentation is faster, without question. But it works best when used with Apple Compressor, rather than Final Cut Pro. Since this is a Compressor/Final Cut Pro feature, rather than macOS, you won’t see the same results using Adobe Media Encoder or Handbrake.
NOTE: An M-series Ultra SoC, because it has four media engines, rather than two in the Max, would be significantly faster, but, as I don’t own an Ultra computer, I don’t have a way to test this.
8 Responses to Export Segmentation in Final Cut 10.7 and Compressor – Faster But…
Well…..I have a MacBook Air M2, so this does not apply.
I would love to try this.
LJ:
Great info as always. I have a mac mini m2 pro running on Sonoma. As you cite above, Allow export segmentation is not an option for me.
DJ
This thing that separates the video into two parts and then you have to export them again together, this causes a slight loss of quality, checked, and therefore could it be that this is why there is a change in size with respect to the export? without segmenting?
Liborio:
Your understanding is not quite correct. What this does, in essence, is divide and export a movie as multiple sections, compress these sections simultaneously, then join those sections into a single movie. No duplicate exporting is used. My GUESS as to the smaller file size is more efficient use of hardware encoding, but I haven’t done any testing to verify this.
Larry
I see my comment is a total mess.
What I mean, is compressor/FC divide the project in creates 2 parts, excactly same length, then combine them again in ine final file, I see the bit rate is slighty different in both files, so my understanding is, the final file is compressed from the 2 separated previous files, or as it is VBR, do 2 files with different bit rate can be combine in one file without rendering them again?
[In other words,] first, the apps compress the project in 2 separated movies/segments, then, merge the movies/segments and compress it again in a final one.
Iiborio:
The segments created by FCP/Compressor do not need to be the same length. As long as the segments are joined at an I-frame, the length is immaterial. Also, compression bit rates can vary by frame within the same movie with no problems.
When using variable compression, that which determines bit rate – assuming the frame size and frame rate remain constant – is the amount of movement between frames and the amount of detail in each frame. (Solid colors compress very small, leafy trees waving in the wind require high bit rates.)
The compressed segments are simply merged, without further compression, when the final movie is assembled during the compression process. All compression is done from the master (high-quality) file, and is only performed once. Compressed segments are NOT recompressed into the final assembled compressed movie.)
Larry
[…] Larry Jordan notes that this feature works in Compressor, too. As he notes, “Export segmentation is faster, without question. But it works best when used with Apple Compressor, rather than Final Cut Pro.” […]