Losing frames with Firewire IEEE 1394A

[Drelletje]

Hi all

Using Firewire IEEE 1394A, when I capture video from my digital cam a couple of frames go missing (around 2% in total) at fixed intervals .

Could this be a driver problem? If so, any idea where I could get a better driver?

Tx a lot in advance!!

D.

[VideoMann]

Could be many things:

1.CPU not fast enough
2. Other processes/programs running in background (Turn-off Antivirus)
3. Hardrive not fast enough (should be 7200 RPM)
4. Other component that shares the same IDE slot is slowing things down
5 IRQ conflict (2 components are conflicting)
6. Graphic capture card not fast enough (may help to lower the resolution on the monitor or relieve some of the workload by changing parameters)
7. May be a faulty or handicapped 1st Generation Firewire card
8. Not enough RAM
9. Lower the video size (picture size) to decrease the load on the capturing. Slow computers may drop many frames when the capturing resolution is 720x480 but may do fine at 300x240 .
10 Hardrive needs to be defragmented so it can put the video chunks all closer together otherwise your hardrive takes too long to find empty spaces to write causing drop frames.

Items in bold are the most common causes that I can think of

[Drelletje]

Tx a lot Videomann , I'll try and make adjustments then, corresponding to the possible causes you outlined, starting with the ones in bold face.

D.

[jtor]

I'd suggest you check recommendation #10 first (defragment), then #2 (background apps running), then (or) #5 (IRQ conflicts); whichever is easiest for you to check first between #2 and #5.

I've done firewire transfers on a 500MHz machine, with 128MB RAM and a single HD (which was a 5400RPM), on-board video with 4MB video mem, with no problems. I think your system is OK, as firewire is NOT as demanding as analog capture.

You might want to check Canopus website, as they have some type of benchmarking utility, just to see your system's capability.

Can you provide the details of your hardware (what firewire card, what software you used, etc)?

[Thorn]

I'd agree that defragmenting and endsuring nothing is runing in the background are the first (and easiest) to take care of.

Since DV is only 3.4MB/s few defragmented HDs should have problems. Programs that periodically read or write to the HD can be a serious problem because they hog the system for a few seconds with no consideration. Microsoft's fastfind and similar programs (especially AV programs) tend to be terrible.

Also, I don't know what program you're using to cap, but I know Virtualdub (just drawing a parallel to the analog world) has an option to disable write buffering. Buffering can cause problems because a bunch of stuff is written when the buffer fills up, but something can get lost while the write occurs.