Recently, I wondered whether Final Cut Pro exported faster if you rendered the timeline before exporting. The answer surprised me!
My test system was an M2 Max Mac Studio, connected to an OWC Thunderblade SSD RAID. Background rendering was turned off.
WHAT I DID
I created a ten-minute (bottom red arrow) 4K project (top red arrow) composed of 44 different ProRes 422 4K clips; with effects as shown in the screen shot above.
The primary storyline contained ten 4K clips, using straight cuts and no effects.
Compound clip 1 contained sixteen 4K clips with the following effects:
Compound clip 2 contained eighteen 4K clips with the following effects:
(The Project Settings window in Final Cut Pro.)
I then measured how long it took to export this project in three different ways, using five different ProRes codecs.
For extra credit, I also timed how long it took simply to render the project, without exporting.
WHAT I LEARNED
Fasten your seatbelts, this is pretty stunning.
When this project was unrendered, (top line in the table above) it took the same amount of time to export it into:
When the default ProRes 422 render setting was used (second line in table), export times were exactly the same as if the project was unrendered, except when exporting as ProRes 422.
Even more surprising, it took the same amount of time to render this project without exporting as it did to render and export the project across all five codecs! (Bottom line in the table above.)
NOTE: ProRes Proxy is not available as a render setting.
However, if the project is fully rendered using the same codec as the export format, export times are significantly faster. (Third line in the table above.)
In this screenshot from Activity Monitor, the key readings are in the lower-left corner:
Notice that regardless of the export format, rendering required essentially the same import data bandwidth. Export bandwidth increased based on codec file size.
NOTE: What this suggests is that FCP always re-renders from source media whenever the export format does not match the project render format.
However, when a project was already rendered in the same format as the export format, output was MUCH faster – 3 – 5X. For example, in this screen shot FCP was transferring media at almost 2 GB per second for ProRes 4444! (ProRes 422 was only a bit slower at 1.5 GB/second.)
NOTE: Actual export speeds will vary by computer system and storage bandwidth.
I wasn’t expecting this result. My take-away is this: To export at the fastest speed, set the project render codec to match the format you need to export.
Then, to save time, turn background rendering on to render as you edit. If you leave background rendering off, don’t worry about rendering before you export because it won’t save you any time.
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