Dropped frames stop capture

[Don Watson]

When capturing a tape via firewire from my camcorder to my iMac and Final Cut Pro, if frames are dropped, the capture stops and all capture seems to be lost. A similar thing has happened if capturing live via firewire without recording to the mini-dv tape. Is there a setting change that will allow a certain number of frames to be dropped without stopping the capture? If so, how many frames can be dropped before it becomes noticeable, especially if doing a multi-cam edit? Also, what should I look at to eliminate dropped frames during capture besides cleaning the heads on the camcorder? Any help would be appreciated.

[bladeaudio]

Usually frames are dropped when your computer can't keep up with the capture. What speed hard drive are you capturing to? Is it at least a 7200RPM drive? Is it the same drive as your OS? Usually its best practice to use a secondary drive for capturing video.

Is the drive you are capturing to almost full? As a drive fills up it slows down. You may also need to defragment the drive before capturing so that, so that the file can be capturing in a contiguous location.

Another reason may be RAM, if your system doesn't have enough RAM to keep up with the capture it will drop frames, but usually the hard drive is the main reason.

[cmchamp]

Don
What CPU and specs do you have? Also, what camera and other FW devices connected, if any.
C.

[katanna]

Also, what should I look at to eliminate dropped frames during capture besides cleaning the heads on the camcorder?

This wouldn't do anything to help as the dropped frames come from the software side of the Mac, not the hardware side of the computer.

I was having this problem when I was capturing to the internal hard drive. I got an external drive and it fixed the problem. You can get a 1 TB firewire drive for under $150 (shipped) these days, so even if you buy something smaller there is no reason to not get an external drive. (And remember to get a firewire hard drive... USB isn't fast enough.)

To answer your question: Under "User Preferences" in the "general" tab there is an option to "abort capture on dropped frames" (right hand side, sixth option down). However, I would not suggest doing this as you never know how many frames are dropped... it may be one, it may be 20+.

Matthew

[Don Watson]

Thanks for the replies. The iMac has the 2ghz Intel Core 2 Duo with 1GB of RAM, 40GB left on the 150GB internal drive. I am upgrading to the maximum RAM today to see if that helps. I have tried recording to both the internal hard drive, same one that has the OS, and have recorded to an external USB HD as well as an Iomega HDD1H firewire drive. I originally captured to the firewire drive but capturing via firewire and using a firewire drive didn't seem to work well. There were problems getting the iMac to recognize both devices at the same time (Canon GL2 and Iomega HDD1H - speed unknown). I'll try the firewire drive again along with the increased RAM to see what happens and to refresh my own memory on what problem I had when using the firewire drive.

[bladeaudio]

If you use an external USB drive, it must be 2.0. USB 1.1 does not have enough through put to support DV video capture. So, make sure the external USB drive you were using is USB 2.0 and 7200RPM and it should work fine for capturing.

1GB of RAM should be enough to capture without dropped frames. In a pinch I've captured DV video on my wife's laptop using an external hard drive without any dropped frames, its a 1Ghz with 512MB ram. Using the USB2.0 ports for the hard drive and the firewire for the camera input.

I would also second the comment earlier that you don't want to "turn off" the stop on dropped frames setting. Dropped frames are very ugly!!

[cmchamp]

Unfortunately, since about 2000, Apple only puts 1 firewire bus in their machines. That said, Canon's don't play nice with the other FW devices, so if you use an external drive onto which you capture, it must be USB2.0.
I don't have any trouble with Panasonic or Sony cameras, but the Canon XL1's, GL1's and GL2's I've had to use over the years just won't play nice with other FW devices.
C.

[bladeaudio]

but the Canon XL1's, GL1's and GL2's I've had to use over the years just won't play nice with other FW devices.

Interesting, I used to run an XL1s in to a PC firewire card AND a DVCAM deck through a Datavideo firewire hub and didn't have any issues. I did this the first time on accident and was surprised that it worked.

[Don Watson]

I'm not sure what made the difference but my capturing of 3 different tapes, plus live capture of the morning service, went fine this week. I used the same USB hard drive (partitioned) that I had in the past but I cleared the one partition of everything. Also, I did upgrade the iMac's RAM to from 1GB to 4GB. I lean more towards the solution being just clearing out the USB drive since I had experienced dropped frames on a Mac Pro with 4GB of RAM using the same drive.

While I am thinking of USB scratch disks, any comments on using a USB flash drive as a scratch disk? With the price of flash drives coming down, along with their small size compared to the 500GB USB drive I am using now, I had considered giving that a try. The smaller drive would mostly be a convenience factor at this time

Thanks again for your help. It is great to get so much input.

[cjlowe]

Originally Posted by cmchamp

Unfortunately, since about 2000, Apple only puts 1 firewire bus in their machines. That said, Canon's don't play nice with the other FW devices, so if you use an external drive onto which you capture, it must be USB2.0.

Seconded! I had a capture to a LaCiE 7200rpm firewire drive failing due to dropped frames (back when 7200rpm was considered great). It took me a fair bit of investigating... basically the Canon camera was streaming video at something like 80mbit/sec to the computer. It was also forcing the firewire bus speed down to 100mbit/sec (FireWire 400 is 400mbps standard, but does have other speeds it can run it, 100mbps being one of them), meaning there was insufficient bandwidth to grab the frames from the camera, then send them back to the firewire drive on the same bus.

The solutions when you hit this problem are unfortunately:
- Use different FireWire busses (but Apple only put one on the computer...), or
- Add an extra FireWire bus with a PCI card (not possible with an iMac), or
- Don't use FireWire cameras (rarely an easy decision), or
- Don't use FireWire disks (eg use a USB or internal disk for capturing, then move it to the firewire disk when done).

(All just mentioned as a conversational thing - your problem probably isn't the above...)

[cmchamp]

CJ
Here's a funny thing. Apple used to make their top of the line CPU's with 2 FW busses. In fact, I still have one of the last in my basement which I use to capture when I can't capture multiple cameras direct to disc.
There's a reason, I keep telling my wife, that I keep a now 11 year old Apple around.

And just for further clarification, I have only had issues with Canon's XL1, GL1 and GL2 series cameras. I have not yet used another Canon to know if it's product range wide. I would only assume that their HD cameras would have updated past a FW100 interface.

C.

[Roxio]

Originally Posted by cmchamp

CJ
Here's a funny thing. Apple used to make their top of the line CPU's with 2 FW busses. In fact, I still have one of the last in my basement which I use to capture when I can't capture multiple cameras direct to disc.
There's a reason, I keep telling my wife, that I keep a now 11 year old Apple around.

And just for further clarification, I have only had issues with Canon's XL1, GL1 and GL2 series cameras. I have not yet used another Canon to know if it's product range wide. I would only assume that their HD cameras would have updated past a FW100 interface.

C.

Which CPU is that in the basement? G4/400? And yes old Canon DV gear sent more packets down FireWire than other brands, but most software had to figure out ignore those packets. BTW, I keep a FCP2/OS9/G4 system around in case I get XL1/GL1 footage that needs the FCP2 Auto Sync compensator that was added once file sizes went past two gigs.

If only today's kids knew how easy they have it...

Rosco