Oh my goodness! I have the same problem as you too! This has been happening to my VirtualDubMod ever since the sounds of my comp went berzerk on me. Can you help me please? I use VirtualDubMod to hardsub and split videos and then I upload them to youtube. I really want to upload the rest of the drama that I’m currently uploading, Sweet Spy. But VirtualDubMod keeps on showing that warning issue. Csn you PLEASE help me?
how do u hardsub videos using virtualdubmod?
Try this besides FFDSHOW : http://www.free-codecs.com/download/ffvfw.htm
Thank you Alex for the link
[digging up this thread]
Those are probably encrypted with its DRM. Throw them away unless you know a solution to deal with them.
thank you Alex for the link 
my virtual dub worked just fine for two weeks looking for best output settings for my HDD player now it just freezes have tried changing settings nothing jams half way through the movie i hav already converted four times wanted to try one more setting set then bam it just doen’t convert it jams
mitty, download k-lite codec pack FULL and do a FULL install for everything. fixed xvid issues for me
Very late reply to woxx & Kalin...
Your problem is the DRM-encryption of several WMV files.
Hi,
I’ve got similar problem like people before. I want to compress uncompressed .avi to MPEG-1 and MPEG-2. It is possible but when I want to open compressed MPEG-1 (or MPEG-2)file created by me error message is written (Couldn’t locate decompressor for format 'MPEG'(unknown). VirtualDub requires a Video for Windows (VFW) compatible codec...).
Can somebody help me please?
Thank you.
Just downloaded the application and all’s well
http://www.free-codecs.com/Nic_XviD_Codec_download.htm
i have the same problem but the alex asnwer worked to me
Help! i can’t open any avi file with VirtualDub, I get alex’s error message: “Couldn’t locate decompressor for format `WMV3` (unknown)VirtualDub requires a videro for Windows (VFW) compatible codec to decompress video. DirectShow codecs, such as those used by Windows Media Player, are not suitable."
i tried installing wmv9VCMsetup and codecs in steps 8 and 9 linked above but i get always that error, can anyone help me? thanks
(to wmyrtle)
Are you sure VirtualDub asked for WMV3 for the fourcc? Are you sure you downloaded the right file + the download completed? The file is exactly 693,840 bytes. Redownload it just in case.
http://www.microsoft.com/windows/windowsmedia/download/AllDownloads.aspx
(On first drop-down menu select “Codecs Installation Packages” and on the second one pick “For Windows Media Video 9 VCM).
Make sure you install the file after you download it (we once had someone complain they couldn’t play Indeo files after they downloaded the codec - only to find out it was because they didn’t install it...) You should see “Setup Complete!" when you’re done with the installation. Maybe reboot once. Then try opening the file in VirtualDub.
“Couldn’t locate decompressor for format `xvid` (unknown)
VirtualDub requires a videro for Windows (VFW) compatible codec to decompress video. DirectShow codecs, such as those used by Windows Media Player, are not suitable.
Can somebody help me?
I found a lot of media files required this codec to run
can somebody help me. I’m having problem with my virtual dub. Everytime I tried saving a file, virtualdub crashes and I keep on getting this message.
An out-of-bounds memory access (access violation) occurred in module 'fun_avcodec'...
...reading address 00000018.
what does it mean?
thanks alex