Droppped Frames = Windows Video Buffers?

[Bstansbury]

I'm having trouble with dropped frames out of my Vdub capture ( like I see that many others are having), so I started reading all of the help in VirtualDub,.. which is very good education for anyone wanting to learn more about video capture.

The help section has a couple of explanation on why there are dropped frames and makes suggestions on how to improve our systems to get rid of them,... such as changing the PIO data rate on individual drives in the Bios, fixing the location on a drive were the data will be faster, etc. etc.

One of the suggestions was to "increase the number of Video buffers". I'm sure this is hidden somewhere in the Registry, since I don't think that Windows ME uses anything like the old "Config" files were we could control buffers. Does anyone know I can go in Windows to change the video buffers???

Also, one other tid bit of info. You can't believe how sensitive the settings are for your processor if you are trying to capture, via MCC, MPEG data. I now know that what I thought was a good processor for everyday work, is a pig for doing video capture. Capturing AVI is no sweat since it hardly every gets the CPu usage above 25%,.. but even at that there are dropped frames, so something else is going on,..like traffic jams. Anyway, my system is a Duron at 700 MHs, 256MB, 80GB hd (7200 ATA 66). In recording an MPEG-1 file, 360x240 @ 0.8 MBs in MMC the dropped frame rate was about 1+%. AT 1.6 MBs it was 10%. I stepped up the processor to 770 MHZ and 117 FSB and the drop rate went down to about 3%. I then dropped the FSB (front side buss) back down to 100 MHZ and jacked the processor up to 800 MHZ. This little change pushed the dropped frame rate up to 12-15%. The Buss has more to do with the capture than the processor.

The bottom line is,,,this show how sensitive our systems are when we don't have a really fast system. I've seen posts from people who have units up in the 1.6 GHZ, 266 MHZ FSB, 80 GB drives with ATA 100,... This is what it takes to really capture MPEG quality data. I wish I knew a year ago when I built this system that I was going to do video. It would have been worth the small amount extra to get me up to where I should be.

I'm going to find every place where I can get the best performance and tune my system, which I really never had to do before,...because it was fast enough to do anything I want to do,.............Yesterday!

[eclipsed4evr]

Yeah i do have a very similar system as you do, and i tried to cap full frame vid(720x480) and had HUGE amounts of dropped frames. CPU was at 100%. I thought a 700MHZ was able to cap in full frame? I'm using the Huffy codec also. Looks like time to upgrad the ol computer or can i make this work somehow???

[Bstansbury]

I forgot to day that if you read a lot of other peoples comments on the forum, you'll see that many others are giving up on trying to capture real time MPEG and going with lossless AVI, editing the AVI data so you can filter it, take out the bad scenes, etc., and then using TMPEGen to render it into a good MPEG stream. Then you can make a VCD, SVCD, whatever,... the answer is that you don't do this in real time on one pass in "Our" systems. A lot of people are still saying that this is the "Only way to go" to get the best quality.

Like I said, I'm still having small problems capturing clean AVI, without jitter, and good sync., but I believe I can solve these problems because I see on the forum that many others with similar system to mine have done it and are far ahead of where I am. There is an enormous amount of information our here,... it just takes time to wade through it because everyone has a differnet CPU, operating system, Video card, and of course, 15 different kinds of software,....and not to mention,... 100 opintions on 10 ideas.