View Full Version : Dropped frames.

28th February 2002, 09:38
Okey here's my problem, I been working with settings for my card to produce the best quality possible. First I was using WDM drivers with IuVCR, but then yesterday, I decided to test my VFW drivers. The quality was improved on first sight. Although the colors got smudged with YUY2 when using uncompressed. Huffy worked fine but I just don't like the idea of using a compressed format. So I decided to test uncompressed RGB. The quality was awesome, and I then converted it to SVCD and I was overwhelmed. It was better than ever.

Here's the bad part though, I get dropped frames. So I tried rgb-16 and I didn't get any loss. But the quality wasn't good enough.

So here's my question, what might cause this drop? Can it be the HD or something else?

My system's specs:
Athlon 1333 Mhz
12 gig 5400 rpm, and one 40 gig 7200 rpm.

I am capturing to the 40 gig, and I have Windows on the 12 gig.

Any questions, then just ask.

Thanks in advance!

oh by the way, I'm capturing at 480x576 using a Pinnacle PCTV card.

28th February 2002, 10:23
MOst likely it is your HD that can't keep up with the large data rates (20736000bytes/s, I assume you use 25fps PAL :confused: ). Give Huffy another try in RGB mode, it is a lossless compression so it shouldn't affect quality of captures.

28th February 2002, 11:14
I was up quite a long time last night. So I never had the chance to test Huffy with RGB24. I'll test that the first thing when I get home.

If anybody else has any suggestions then I'd be happy to see them :)

28th February 2002, 19:58
how many dropped frames do you get ? too many ?
the pinnacle got an audio input I assume,
so it is probably not the audio recording

if you try to capture a PAL movie with more than 25 FPS you will of course get dropped frames

28th February 2002, 22:33
I don't use the audioinput. I use the sound directly to my line in.

Well it stays at 25 fps for a while, then it starts dropping average frame to about 22-23, and with that. Alot of drops.

I've tried using Huffy with RGB24, but the truth is that it's not as good looking and the interlace is different. Don't ask why. :)

1st March 2002, 08:33
Two more questions:
Win9x or Win2k/XP? I just switched to 2k and my first tries looked very much better performancewise than 98.
What is your CPU usage when you use VirtualDub for capture? If it hits 100% then you have something running in the back that affects your performance.

1st March 2002, 09:01
try capturing without audio

this almost looks like the buffer gets filled and not cleared anymore
on the other hand 23 fps sounds like your source is ntsc film

anyway, try capturing without audio

1st March 2002, 11:08
I'm not capturing an NTSC, it was an example. It drops from 25->22 and then it might go up again.. and then down to 21. It varies.

I am using Windows 2000 when capturing and the CPU usage % is 25.

1st March 2002, 18:16
Hi there,

I've tried iuvcr in the past and it kinda works sometimes i did a 5min cap but that was about the limit before sound totally desynced and I even tried raid but the fps go up and down :(

Anyway I heard on irc you can now use avi_io with wdm driver and get full vertical resolution by running a patch on the driver I hav'nt tried it yet but it's at


good luck!

1st March 2002, 20:06

sorry was just an idea...
anyway did you try a capture without audio yet ?

1st March 2002, 20:58
Thanks for your post unit,
but as I stated in the post, I am now using my VFW drivers, and thereby VirtualDub :)

I haven't tested capturing without audio yet, I'll do it... any hour.

2nd March 2002, 10:36
I just tried disabling the sound while capturing... no success.

Still the same "results". Drops after a while of capturing... varies between 15-45secs.

5th March 2002, 10:28
okay, at least its not the audio ;-)


5th March 2002, 10:37
I have the same problem as you. A large frame dropping that occurs with pinnacle's vfw drivers only under win XP/2000, whereas they work finely under win98. I believe this is a bug issue of these drivers.

One solution that worked for me is to remove the drivers and reinstall them. Capture then works correctly until reboot.

Another solution is to capture under win98.

Another solution is to use wdm drivers.

5th March 2002, 11:13
I've tried WDM drivers. The colours look better and it seems to work, but the interlace is... strange. It seems to change pattern more often than the VFW does.

Oh dear, I'm all lost in the forrest of capturing.