BSPlayer and InterVideo AC3 filter
 

How can I make them work together? I've re-registered the filter, set all BSPlayer settings to use it - and still ac3 won't open, as if the filter didn't exist!

But when you play a video file with AC3 sound, in filter menu what is displayed (rightclick->options->filters with the file loaded) ? Odio dekoda ? FFDshow ? AC3Filter ? If so, try to uninstall the other filter used. If it is FFDshow, first check if it is not the default decoder for video too, in same filter section.

It does not play neither video with ac3 sound nor ac3 files alone, because I have deliberately turned AC3Filter off to try to use InterVideo's filter - which, as I have already said, refuses to function. So ac3 files won't even open, as if there were no ivivideo.ax etc. registered!

ivivideo.ax is for video decoding not for audio. You need iviaudio.ax to decode audio streams.

I know. I said "et cetera" - that is I've got all InterVideo filters registered, unregistered and re-registered many times (including iviaudio.ax). BSPlayer still acts as if they did not exist.

Strange thing. I have also an "user kit" for intervideo (I personally don't use it anymore, I use Elecard decoder because of large number of files on wich intervideo decoders failed to work properly) that includes iviaudio.ax and mpgaudio.ax. But when I run the registering command from hdd:

regsvr32 /s iviaudio.ax
regsvr32 /s mpgaudio.ax

filters get registered and I can use them. Do you have the package on hard drive or on a removable media ? Be sure you don't remove the files from your system.