VirtualDub comes in two versions, the regular 32-bit x86 version, and a 64-bit version for processors that support the AMD64 architecture. The AMD64 version has some differences from the 32-bit version.

There is currently no version for the 64-bit Intel Itanium architecture.

System requirements of VirtualDub for AMD64

In addition to the regular system requirements, the AMD64 version of VirtualDub also requires:

• A CPU that supports executing AMD64 code. As of this writing, this includes the AMD Athlon 64, AMD Opteron, and Intel Xeons with EM64T.
• Windows XP x64 Edition, Vista x64 Edition, or another version of Windows which natively runs in AMD64 long mode.

It is not possible to run the AMD64 version of VirtualDub on a 32-bit version of Windows even if the CPU is 64-bit capable.

Differences between the x86 and AMD64 versions

Not all functionality has been ported to 64-bit, so the selection of video filters is reduced compared to the 32-bit version. In addition, some functionality which is supported is not fully optimized compared to the 32-bit equivalent, so the 64-bit version may or may not be faster than the 32-bit version for your scenario.

Due to an OS limitation, 64-bit programs cannot load 32-bit DLLs, and vice-versa. As a result, use of the 64-bit version of VirtualDub requires 64-bit video codecs and 64-bit video filters; 32-bit video codecs will not show up in the video codec list or be available for opening AVI files, and 32-bit video filters will not load. In addition, AVIFile drivers must be 64-bit to be used on load; in particular, VirtualDub for AMD64 cannot be used with the regular 32-bit version of Avisynth.