Firewire and dropped frames when capturing video

When was the last time you defragmented your hard drive? A badly fragmented hard drive can result in dropped frames as the computer scans the surface of the disc for free space to record the data on. Also, what compression are you using for your video? Uncompressed files are much larger than compressed files and can result in dropped frames if the computer can write the files onto the drive fast enough. Use your video capture software to set up the correct compression for your purpose.

I worked with two boxes. One was quite new and therefore I don't think fragmentation was a problem with it. The other has gone a long time without defragmentation and I need to give that a try.

After a few attempts I focused in on using "dvgrab" in Linux. Running from the command line and not doing any compression (as far as I know) made it seem as streamlined as possible. Thus, I was thinking it had the best chance of success.

Will a modern PC compress video fast enough that adding the burden of compression can offset the bottle neck of hitting the hard drive? I was thinking that "save it now, compress it later" was my safest approach. Is that backward?

Thanks,

Bruce

"Will a modern PC compress video fast enough that adding the burden of compression can offset the bottle neck of hitting the hard drive?"

That would depend upon the speed of your computer, the number of background applications running and the size of your RAM. Shut down all unnecessary background applications to free up RAM. When I first tried recording movies on my PC, I tried to capture it uncompressed for highest quality, then compress it down to size. It resulted in a lot of dropped files. When I set my capture device to compress the data though, it resulted in a much smoother capture, with far fewer, if any, frame drops. I hope this helps.

Which Firewire did you buy 400, 600 or 800? Low latency??

What software?

Is this a laptop? Desk top with Q6600 is stability in a box.

What type hard drives and how are the channels configured?

My Firewire card is a PCI bus "no name" card from a clone shop. This may not have been a good choice. In Googling the problem I did not trip accross 400, 600, 800, Low latency or any other specifications that would allow me to judge one Firewire solution against another. I can Google them, but I would appreciate any summary and/or advice you could give me on any specifications I should be looking for.

By chance, does "Low Latency" mean that the card has some buffering on it?

I tried several software packages available in Linux. The command line program "dvgrab" is one I ended up with since I assumed (possibly incorrectly) that no GUI and Linux would reduce my overhead. One box is dual boot, I don't recall for sure if I tried XP, but I think I did.

The box is a desktop. I have two of them with Asus motherboards in them. One is a 2 GHz 32 bit box, the other is a 64 bit box and probably 2.4 GHz. The 64 bit box had an IO Meter report that I couldn't believe. It has been a few months, but I think it was aroung 50 MB/sec. Whatever it was, it was WAY ABOVE the numbers I had seen on other boxes.

Both boxes would go a minute or two without dropping a frame, then drop one or two, possibly drop one or two a few seconds later, and then return to going a minute or two (sometimes 3-5 minutes) without dropping a frame.

I don't know anything about Q6600 or configuring hard drive channels. I will Google them but I would also appreciate any advise, info, key words to search on, etc.

Thank you,

Bruce

I suspected Asus may have been in use. When gaming rocket ship acceleration is wonderful but when processing media "stability" is key. Through put speed is a consideration certainly but stability will get more done effectively and efficiently; akin to the "tortoise and hare" story.

I've heard the term 'boxy station-wagon' used to describe the performance of Intel vs. Asus, but the station wagon (stability) is what's needed for media . In the following links you will notice Asus in use but only by those knowledgeable of system conflicts.

Many of us when initially processing A/V make the mistake in assuming a good gamer is a good media pooter. However an exceptional media pooter can dbl as a gamer if the consideration were a principle during the build, Caveat Emptor!

Regarding hardware/software; anything of value in this world has a price...

Here are some sources for you:

www.adobe.com/designcenter/dialogbox/pshistory.html

www.sonycreativesoftware.com/products/vegasfamily.asp

www.sweetwater.com - contact Matt Adams

www.adkproaudio.com

www.newegg.com

www.matrox.com/video/en/home/

This will get you started.

Q6600 quad core processor with unique audio/video rendering capability, in my opinion.

Thank you, I'll read the links.

Bruce

Oops I forgot to explain low latency; referring to processing within an interface/Video card etc. lessening load upon the CPU

Warning: Do not ever pull the Firewire from the port while in use, a mother board fire can occur.

One thing not yet suggested - could the fault be in the camera or tape?

A small scratch on the tape may not be seen on playback, but throw up an error on the frame when digitalised.

Another option may be too small a buffer within the camera - if built for FW400, and connected to FW600/800, the computer side should know, and alter speed accordingly but may occasionally use up all the buffer.

The clock speed and processes of the computer are not as likely to affect the outcome as with USB, due to the nature of the interface.

USB is controlled from the processor, thus using resources across the computer. Firewire has its own controller, so should be able to operate efficiently unless the destination drive is being used by other programs. Have you tried using a dedicated Video HDD?

Also, check the buffer sizes on both the camera and card, lest they be vastly different.

I am currently digitizing old "normal 8mm" tapes. The old camera is not Firewire. I am using a ADS Tech Pyro A/V Link that I got from videoguys.com. It converts NTSC baseband into Firewire DV. (I will be getting a better camera in the future, but not at the moment.)

Thus, my question of the moment is: Is there any way for me to know if the "dropped frames" are being dropped inside the PC or outside the PC? As I recall the only useful information I get on the screen is "n number of dropped frames".

Bruce

Possibly - you can attach a monitor to the ADS unit, and watch from there. Whether you would spot the odd dropped frames.....

But seriously, reading here, the software is likely to be giving info on the A to D process rather than the firewire link.

You have already had some excellent tips, I am just trying here to fill in a few further areas that might help.

1) Could you accurately describe your PC for us please? Memory size vital, 2 GB or more is best.....fast memory!!!

2) The need for a disk to be defragmented is paramount, even for normal working.

3) in fact you may want to buy a fast SATA disk for all of your video work ONLY. Read the magazines and test results, go for speed and quality/reliability, not just size....(Size is not always important in EVERYTHING.....), but if your C: disk is slooooowwww, you will still get problems when your program (or windows) goes off to find something that resides on the C: disk. You can improve this a bit, if you reinstall the program (not windows) to the new faster SATA disk.

If the C: disk is stillö slow, buy a new C: disk too, or just install a second copy of Windows on the new SAT disk and only boot it for when you want to do Video stuff, keep it mean & lean.

If you are using Linux, read Linux for each time I wrote Windows please....

4) I guess you have an unbuffered Firewire card, you may want to try and buy one with a big buffer on it.....the one you have appears to use your PC memory (you DO have at least 2 GB memory of course??? Less is useless!!) and the PC processor, not a good idea.....

I found a message for Linux users (in German) that a certain Kernel had problems with the buffer sizing, maybe you have the same problem Kernel?:-

[FreeBSD] Schwachstelle im Firewire Treiber des Kernels - FreeBSD-SA-06:25.kmem

Maybe you can find details for it in English somewhere....."Schwachstelle" is weak point,"Treiber" is "Driver", "im" is "in" in English.

For such problem reasons, I bought a Hard Disk video Camera a few years ago with 30GB, I have not regretted the purchase at all. The 30GB does a 2 week holiday for us with time left over, probably a 4 week holiday in fact and takes marvelous still picture (up to 99,000 on the hard disk.....

It allows over 22 hours of video at best quality, naturally much more at a lower quality. SP is also pretty good, but LP is too grainy when moving a lot on some edges....the camera is connected via a USB and I have never ever dropped a single frame.....the files need almost no changes to be burnt on a DVD (except for normal editting of course!)

For those thinking of a purchase of a camcorder:-

My recommendation is NOT to buy Firewire if possible as some people sadly get problems, (just google Firewire on the web and see!!) assuming that some out there may be thinking of buying a new video camcorder.....not having to change cassettes is good.....not having a delicate cassette mechanism is also VERY good.....hard disks are far more robust and almost no chance of getting dirt or sand in the mechanism either.....they also do not jump if jogged either as some cassettes do.....also, no need to buy or transport cassettes of course......wear is minimal on a hard disk!!! But cassettes wear out if used a lot....

I hope this helps.

My recommendation is NOT to buy Firewire if possible as some people sadly get problems, (just Google Firewire on the web and see!!)

Sad! Make a decision based upon what others Google

try it for tires

Quit it

Firewire is a simple affair if certain protocols are observed, bandwidth is wonderful. Most problems occur when the 4-P's are discarded, remember them

USB 2.0 may not be quite as fast as Firewire (when it runs correctly) but at least it seems to be supported well on many mainboards and does not suffer from dropped frames!!!

USB appears to be one of the most reliable and flexible interfaces around.....

Not that this advice will help our original poster, but it might help those thinking of buying in the near future!!

If I recall correctly (no guarantees!) Firewire was a Sony product comparable in the grand cosmic scheme to BetaMax. A superior product in some ways, but limited for all applications, thus susceptible to being ignored by the masses. USB thus relates to VHS...

Generic product is IEEE 1394. Apple used Firewire as its name, and the 6pin connector which also provides power. This is where the risk of fire when removing live devices originates, as 30V and 45W can produce quite a spark.

Sony uses iLink as their trademark, and normally the 4pin version.

Reading the Wikipedia article, there is another possibility for resolving the problem, as XP SP2 limits all Firewire devices to 100Mb. A patch is available to increase speeds, but not as yet for Vista.

I do not understand the relationship that you mention, but USB, in spite of actually being slower, is far more reliable.......therefore picture quality with no dropped frames is far superior.

Therefore I would have swapped the comparisons around as VHS especially in the beginning, had really awful quality. In dact it still has not reacher the quality of the Grundig/Phillips VCR2000 machines, nor has it achieved the length of time for recording, nor can you turn over the cassette and use the other side either.....

I believe VCR 2000 had 8 hours on each side in PAL format!!!! But its a long time ago, maybe someone else can elucidate for us!!

My comparison was more of acceptability than usefulness. BetaMax is long gone, VHS remains (for whatever reason). USB is commonplace, FireWire is an aftermarket add-on from what I've seen.

It is now on most Laptops (Firewire), but I still find USB2.0 personally better, in fact, I have many devices that use it and none have ever given me problems on several PCs, and many Laptops....

Hello BruceFlorida:

You certainly have lots of advice from bwire and andy germany (sorry if I got the names wrong).

I was about to mention the use of a dedicated Hard Drive, and Low latency Memory and as much as your system can take. But Andy got there first.

I can't do any better than the clever advice you have already. Can I just say well done for the brilliant advice from you bwire and andy germany.

babybear