Hard disk space 25 Mbps -v- 35 Mbps
 

My EX1 is due to arrive this week but I was wondering if somebody can tell me how much hard drive space is taken up with:

- a 10 minute clip shot at 25 Mbps
- a 10 minute clip shot at 35 Mbps

Thanks,
Keith

I'm no expert at the math behind this so I may be totally wrong, but I think it works something like this:

35 Mbps = 4.375 MBps. So 10 mins (600 secs) = 2.625 GB
25 Mbps = 3.125 MBps. So 10 mins (600 secs) = 1.875 GB

Bare in mind though that HQ mode uses a variable bitrate and the audio is on top, so it will depend on the content.

Thanks Paul, your calculations look right. So taking the higher bit rate of 35 Mbps, 2 hours of footage only takes up approximately 32 gigs of hard disk storage. This seems very reasonable to me. The compression codec must be very efficient. I was always led to believe that HD footage would take a LOT more space than standard DV.

For anyone who needs to do these sorts of calculations regularly, you might want to download my free bitrate calculator (BitRate Calc). There's a Mac and a Windows version available here: http://www.ethreemedia.com/news.html

Don't forget that SP is a CBR codec and the HQ is VBR so your mileage will vary with the HQ codec.

EDIT: I just read Paul's whole post... so, what Paul said.

So it looks like roughly 50min to 1 hour per 16g card in HQ/35M mode.


Not bad!

Hi Eric,

Thanks for your bitrate calculator which I just downloaded. Do you have another version coming that supports terabytes?

Keith

That's a good idea, Keith. I'll put that together and post back here in a week or two.

Better late than never, I suppose. Version 2 of Bitrate Calc is now completed and available for free download for either Mac or Windows. The new version supports Terabits and Terabytes. Just visit the news section of our web site, and you can find it there.

The answer is on the cards, 16gb card at HQ/35 setting (any) is 58 mins on the camera's screen.
So (roughly) 58 mins divided by 6 gives 10 mins (roughly)
So 16gb divided by 6 is 2.66.....

Paul.

Actually a 16GB card isn't really 16GB but ~15.04GB. The capacity on these cards is a bit misleading because they assume 1GB is 10^9 instead of 2^30 as is the case for computers. For smaller numbers the difference isn't that great but as they get bigger, it gets larger faster.
KB---> 2.4%
MB---> 4.86%
GB---> 7.37%
And so on.
Don't you just love the marketing hype?