Sustained Transfer Rates for DV transfer.....

[jennyandgreg]

I have heard a few different numbers here but what is the minimum sustained transfer rate needed on a hard drive to transfer DV from a digital camcorder?

[ktnwin]

Quite simple math, one hour of DV video eats up 13GB of HDD space, so the sustained transfer rate for DV video is:
13 x 1024 (MB) / 3600 (sec) = 3.677 MB/sec

[jennyandgreg]

And DV is a constant as far as quality goes right? At that recording rate I get near DVD quality output correct? I guess where I get confused is based on that level of throughput why would anyone consider RAID for DV capture? It seems like HUGE overkill.......

[The village idiot]

For standard definition DV (DV25) it is gross overkill. Even DV50 is well under most of those requirements.

[flaninacupboard]

correct me if i'm wrong, but the important aspect of RAID is the error protection/backup aspect? i would imagine that's why professionals use it. the only other reason higher transfer is useful, is if you are editing. in orer to mix two scenes and output it in real time (which decent edit suites can do) you've got to lift and drop 11 megabytes a second, more if there's more scene transitions, and even more if you're mixing music as well as the original sound.
however, for straight captruing, you've no worries.

[jennyandgreg]

Whats DV 50?

For standard definition DV (DV25) it is gross overkill. Even DV50 is well under most of those requirements.

[Jester700]

True RAID is redundant, and good for data security. But most PC geeks nowadays think of RAID type 0 as "RAID" when it's not redundant at all. It is a way of sharing 2 drives to increase throughput. But it is LESS safe, as any problem on either disk will hose the data. These are performance geeks, after all.

RAID 0 is not necessary for the low requirments of DV, but IS a great thing for uncompressed or Huffyuv compressed video, which have a much larger throughput requirement. I don't use these, but IIRC the data rates are in the neighborhood of 10MB/s for Huffy and twice that uncompressed.

DV50 is "pro DV". It has twice the data rate of DV (also known as miniDV or DV25). It has less compression artifacts and better color reproduction. It is also mucho expensive, as the cheapest cams are in the several thousand $ range.

[jennyandgreg]

Well that helps, DV50 is definately not what I am looking for. As for the RAID stuff it seems to me that a dedicated drive for raw video capture, and a dedicated drie for processed output video would be the ebst combination. By doing this I would think when I am processing the final product one drive (the raw captured video) is only sending data out, while the other drive (the end product) is only taking data in. Wouldnt this give me the best result with no drive having to deal with the shifts between in and out??

[arcorob]

In a nutshell, YES.

I have two 120 GiG hard drives I use as follows

1) Capture the DV - Formatted NTSF (because files will be larger than 4gig)
Edit using various tools, etc.

2) Render drive - This second drive is what I render to to insure I am not hitting the same drive as the source. I render as DV AVI here because again, it will be large (greater than 4 gig) and I then feed from this drive to TMPGenc to convert to MPEG 2

3) Drive 3 -Uh OH - how many drives does this guy have ? Drive 3 is half of an 80 gig drive, 40 and 40 , both formatted as FAT32. 1/2 of the drive is a backup to my C: drive (drive 4 !!! ) , the other 4 gig is where I store final rendered MPEGS.

4) The 40 gig C: drive, clean of all work files, etc. it is the software heart of the machine.

So in all, I have 4 drives, 5 partitions.

C: 40 gig
D: G: 80 Gig Drive partitioned in 2 halfs
H: 120 Gig drive
J: 120 Gig drive

what is really essential here is my backup of the C: Drive to the D: drive, seperate drive. A drive failure on C: could cost me thousands in software. The half of the 80 gig drive I use as pure backup is basically a 40 dollar insurance policy and WELL WORTH IT. I also keep a DVD backup (Norton Ghost - takes 3 disks) of that drive IN CASE my whole machine gets toasted. Again, cheap redundancy. 6 dollars in offisite disks could save me my business.

Rob A.