VirtualDub 1.6.8

Build 28346 (1.7.8, stable): [February 12, 2008]
[bugs fixed]
* Capture: Fixed crash when starting capture from command line with filters
and preview acceleration enabled.
* Capture: Fixed issues with custom DirectShow filters not reconnecting.
* Capture: Added workaround for audio source switching to "no audio" in UI
due to DirectShow crossbar goofiness.
* Capture: Changing the audio source manually now asks to turn off auto-
switching.
* Capture: Audio source now saves properly when set to "no audio."
* Fixed crash when previewing beyond end of selection with IVTC enabled.
* Added workaround for XviD decompression crashes.

[regressions fixed]
* Filters receive distinct source frame numbers for null frames again.