Hard Drives - How fast is a waste?

"Assuming that ProRes is your densest format, given a "typical" editing situation, how fast does a media drive or array have to be so that it is never a bottleneck?"

If you mean regular ProRes 422:

The calculation is simple. If you work with ProRes 422 1080p video at 30 fps you multiply the number of simultaneous streams you need to process by 20 to know how fast your drive setup must be to handle your media without any bottlenecks. Why 20? Because regular ProRes 422 in a 1920x1080 frame size at 30fps has a max. bitrate of 20MB/s (147 Mbps).

In a typical editing situation a decent FireWire 800 dual disk enclosure (nominal throughput 80 MB/s) will be sufficient to handle this format without any bottlenecks. I know someone who has been editing ProRes 422 1080p for some years now only using single disk enclosures, but I would not advise such a workflow except for single layer projects.

Exceptions:
1. ProRes 422 HD multicam editing with more than three video angles will require a faster throughput than FireWire 800 can comfortably provide. For such projects, as for projects with multiple PIPs, you will be better off with an eSATA RAID system or a small dual disk Thunderbolt drive such as the LaCie TB Little Big Disk (nominal throughput of 240 MB/s).

2. For heavy multicam work (9 angles or more) you will need a very fast RAID such as the Promise Pegasus Thunderbolt (nominal throughput of 490 MB/s).

"Does it make a difference if you are exporting to the same drive that holds the source files? - Or if your rendered files are on the same drive as the source?"


Theoretically the answer is obvious: yes. Because when you read and write simultaneously to the same drive you will lose some performance. But on any decent system this difference will be fairly negligible.

Thanks a ton, Ronny.

This is EXACTLY the info I needed.


- And it makes perfect sense, unlike so much info I've been gathering on other threads & other forums. Once again, it's kind of shocking to see how many pros don't really understand what's going on "under the hood."

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So now I figure I need about 100 MB/s to be truly safe with my worst-case projects. (I'm trying to avoid raid data drives, as I use external raid-1 for backup, and I prefer SSD for internal drives as they run cooler.)

I should be able to get that from a single SSD, though now I have to do some more research regarding TRUE SSD i-o, over time, with non-comressible data.

Wel, I'm getting there!

thanks again.