View Full Version : Causes of framerate drop in capturing?


Ben Boer
March 10th, 2006, 05:27 PM
If it were PC spec/issues related, please explain what the main causes of a drop in frame rate, during capturing (DV) would be.

Robert M Wright
March 16th, 2006, 09:45 AM
There can be many causes. Multi-tasking your computer during capture can cause dropped frames (don't mash a spreadsheet at the same time you capture). Badly fragmented hard drives can cause dropped frames. Those are two biggies.

David Kennett
March 16th, 2006, 04:45 PM
Make sure DMA is enabled on the capture drive.

David Ellis
March 16th, 2006, 10:01 PM
how do you enable DMA on captured drive?

David Kennett
March 17th, 2006, 09:09 AM
David,

DMA is enabled in BIOS, and is probably enabled by default on newer computers. Getting into BIOS is obscure on my Toshiba laptop - usually hit delete during boot-up.

Before pursuing this further, if you send me an email, I can get your address, and attach a small program that checks drive throughput for DV capturing. I don't see a way of sending attachments through the forum. That pgm will tell you if it's drive performance or something else.

Glenn Chan
March 17th, 2006, 05:02 PM
DMA can also be enabled/disabled in Windows. Windows will try to run the drive in DMA mode, but may drop down its speed if the drive is generating errors (to the PIO interface mode). This can happen easily with CD/DVD drives, since scratched CDs will generate errors.

To make sure Windows hasn't disabled DMA (or the fastest form of it that the drive supports):

Go to control panel
system
hardware tab
device manager
IDE ATA controllers- something like that
expand that branch out
get properties on one of the channels
go into the advanced tab
Read off the transfer rate mode.

Also do that for the other IDE channel (primary/secondary).

2- DMA in the BIOS will almost certainly be on, unless the computer is very old.

3- Are you capturing to an external hard drive? That can sometimes cause problems. Capturing to an internal drive will work in that case (usually).

DMA/PIO is not a problem for external drives.