Hard disk space 25 Mbps -v- 35 Mbps at DVinfo.net

Keith Malone · February 3rd, 2008, 08:22 AM

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

Paul Joy · February 3rd, 2008, 08:40 AM

Quote:

Originally Posted by Keith Malone

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.

Keith Malone · February 3rd, 2008, 09:04 AM

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.

Eric Darling · February 3rd, 2008, 11:20 AM

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

Andrew Wilson · February 3rd, 2008, 11:50 AM

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.

Brad Vaughan · February 3rd, 2008, 12:01 PM

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

Not bad!

Keith Malone · February 4th, 2008, 05:42 AM

Quote:

Originally Posted by Eric Darling

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

Hi Eric,

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

Keith

Eric Darling · February 4th, 2008, 05:08 PM

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

Eric Darling · April 22nd, 2009, 07:54 PM

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.

Paul Kellett · April 23rd, 2009, 05:37 AM

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.

Omar Idris · April 24th, 2009, 02:53 PM

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?

February 3rd, 2008, 08:22 AM	#1
Keith Malone Regular Crew Join Date: Jan 2008 Location: Ireland Posts: 63	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 Last edited by Keith Malone; February 3rd, 2008 at 09:28 AM.

April 23rd, 2009, 05:37 AM	#10
Paul Kellett Trustee Join Date: Nov 2007 Location: Bristol UK Posts: 1,273	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. __________________ Round 2 GH5,FZ2000

February 3rd, 2008, 09:04 AM	#3
Keith Malone Regular Crew Join Date: Jan 2008 Location: Ireland Posts: 63	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.

February 3rd, 2008, 11:20 AM	#4
Eric Darling Major Player Join Date: Jun 2006 Location: Savannah, GA Posts: 463	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

February 3rd, 2008, 11:50 AM	#5
Andrew Wilson Tourist Join Date: Nov 2007 Location: Vermont, USA Posts: 123	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.

February 3rd, 2008, 12:01 PM	#6
Brad Vaughan Major Player Join Date: Dec 2006 Location: Va Beach, Va Posts: 241	So it looks like roughly 50min to 1 hour per 16g card in HQ/35M mode. Not bad!

February 4th, 2008, 05:08 PM	#8
Eric Darling Major Player Join Date: Jun 2006 Location: Savannah, GA Posts: 463	That's a good idea, Keith. I'll put that together and post back here in a week or two.

April 22nd, 2009, 07:54 PM	#9
Eric Darling Major Player Join Date: Jun 2006 Location: Savannah, GA Posts: 463	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.

April 24th, 2009, 02:53 PM	#11
Omar Idris Regular Crew Join Date: Mar 2008 Location: Middlesex, UK Posts: 28	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?