Calculating Hard Drive Space needed for HD Render?

Jeff Cooper wrote on 9/6/2009, 2:50 PM
Hello folks,

I have a distributor that wants me to render two 95 minute films and a 14 minute documentary in HDV 720-30p intermediate, and they want it send to them on a hard drive.

I'm trying to figure out what size hard drive to buy.

Does anyone know if there's a formula I can use to figgure out how much hard drive space this will require?

Thanks, Jeff

Comments

Guy Bruner wrote on 9/6/2009, 3:06 PM
HDV in 720p has a bitrate of 19 Mega bits per second (Mbps). Or, 19 divided by 8 bits per byte = 2.34 Mega Bytes per second (MBps).

2.34 MBps times 60 seconds/minute = 140.4 Mega Bytes per minute.

95 + 95 + 14 = 204 minutes

140.4 MBpm x 204 minutes = 28,642.6 MB or 28.643 GB

So, you should be able to fit it on a 40 GB hard drive. Why not 30 GB? Because the storage capacity of hard drives is specified in 1000 bits per KB instead of the binary 1024 bits per KB in which we are dealing above. A 30 GB hard drive only holds a true 29.3 GB (even less after formatting). So, go with the larger drive.

Actually, why bother with a hard drive at all? Put it on a USB Flash drive. (I know they specified hard drive, but Flash is so much more convenient.)
Jeff Cooper wrote on 9/6/2009, 3:15 PM
Wow! Thanks for all of that Guy!

Actually, I was thinking I'd put it on a flash drive...

Cheers, Jeff
Guy Bruner wrote on 9/6/2009, 3:19 PM
Yeah, a 32 GB flash drive at Newegg.com is $75, only about $20 more than a 40 GB hard drive (if you can find one). That should give you a 1 GB margin for your files (Flash memory is specified the same way as hard drives).
John_Cline wrote on 9/6/2009, 4:27 PM
Most Flash drives are formatted as FAT32 which has a 4GB file size limit. In other words, no single file may exceed 4GB.

You can format a USB drive as NTFS, but there is a downside. NTFS is a journaling files system and reads and writes to files much more often than other file systems like FAT and FAT32. This is because disk transactions are logged separately on the disk as they occur. This produces a lot more wear and tear on the flash drive and cause it to wear out much faster. Flash drives have a limited number of read/write cycles.

If you still want to do it, here's how...

Right click "My Computer" and select "Manage." Open the "Device Manager" and find your USB drive under the Disk Drives heading. Right click the drive and select "Properties", then go to the "Policies" tab and select the "Optimize for performance" option and Click OK.

Once you do that, open up My Computer and right click on the flash drive and select Format. There you will see that you now have the option to format to NTFS in the File System dropdown box.

After you do this, from now on you MUST "Eject" or "Safely Remove" the drive. Just pulling it out of the USB port can cause data loss.

Another way to get files larger than 4GB on a FAT32 flash drive is to use a file splitter and split the file into 4GB chunks and recombine them later. WINRAR also has a somewhat automated method for doing this.
Guy Bruner wrote on 9/6/2009, 4:41 PM
Good points, John. I believe if you render from Vegas to a file on a FAT32 hard drive or Flash drive, it adjusts the files into 4 GB blocks. So, a Flash drive could be left formatted as FAT32 without causing problems if Vegas is used for editing. NTFS would be better, as long as the drive will be used in a Windows system, because there would be no practical limit to the file size and it would take months or years before the drive wore out from repeated use. If the client is using Apple equipment, leave it as FAT32.
John_Cline wrote on 9/6/2009, 7:55 PM
Guy,

I had completely forgotten about Vegas' ability to split video files into chunks. It's been a long time since I've dealt with FAT32 drives for video purposes. The original poster said that he was generating HDV files. I assume that Vegas will split an HDV render into 4GB chunks like it will with an AVI render but I've never had an occasion to try that.

As to the longevity of flash drives, the new flash-based SSD drives have an algorithm that distributes writes to the drive to maximize their lifespan, USB "thumb" drives do not. That said, I've used a lot of USB thumb drives and have yet to kill one because it wore out.
Chienworks wrote on 9/7/2009, 5:07 AM
I know Vegas doesn't split MPEG renders into 4GB chunks so i would expect that it probably won't do HDV either.

As far as the number of reads & writes, this is probably not much of an issue in this case. Think of it as a one-shot project and the cost of the thumb drive is merely an expense of doing the project.

If you're really concerned about drive longevity then one could pick up a 300GB pocket sized external USB hard drive off the shelf at WalMart for about $65 and have room to store 10 of these projects. That's an even lower cost than the 32GB solid state drives.