VirtualDub captures at 53.33 Fps From 60 Fps Firewire Camera

[kmlee]

Hi to all

Appreciate all the great tips posted by the powerusers here. Thanks a heap!

I'm using a Basler Firewire camera which can give 60fps at 640*480 24-bit colour uncompressed over IEEE1394. But it comes in at 53.33 fps in VirutualDub 1.6.15, even after I set the fps in VDub's dialog.

The latest version of the Basler software has a filter which allows it to be used with DirectShow-aware capture software.

VirtualVCR does the same thing, sad to say, but the basic AMCAP from MS gives an AVI file with the correct rate. However, AMCAP's interface is a bit too basic for my needs.

Any suggestions about what the problem may be?

Thanks in advance for any help

[Cornucopia]

I only see 5 choices:

1. Use AMCap to capture, then use Virtualdub for all the rest.
2. Use Virtualdub to capture, then change the fps with AVIFrate, then do Virtualdub for the rest.
3. Contact the manufacturer of the camera and have them write correct drivers.
4. Get a different camera (DV?)
5. Live with it being the wrong framerate.

Scott

[kmlee]

Hi to all

Thanks to Scott for the reply.

Well, I decided to verify what the software was doing by videotaping my watch set in TIMER mode.

For VirtualDub, the fields in the infobar had:
The leftmost - desired(?) capture rate - 53.33 fps.
Rightmost (actual?) - 38 fps.

AMCAP - of course, 60 fps.

Well, guess what, the capture rate is about 30 fps. Back to RTFM and I overlooked the fact that this camera, like most industrial types, you need to set the shutter manually. At defautls, I guess the driver wasn't happy at being forced to work at some unreasonable rate and modified the requested rate without telling the user.

Some tweaking and there it was! But I wanted a higher shutter time...sigh

Moral of the story? VirtualDub's on the fly update of capture rate is wonderful. Would appreciate it if someone could clarify how the two capture rates are computed and perhaps point to it in the code.

Thanks to all and apologies for not doing enough "RTFM"