AC3 and DTS playback in avi and wma files

[Skunkmaster]

Hello,
I have a few avi and wma files which I know they contain an ac3 5.1 playback.
i am using creative 7.1 sound card and a harman kardon amp which support the format.
when I play MKV files I get Dolby digital and dts sound correctly, but with all other format i get a stereo pcm transmit.
I also use ac3filter with SPDIF, and when I play MKV files I can see that SPDIF is enabled with all other files I get SPDIF disabled.
can someone help me on that?

[setarip_old]

Hi!I have a few avi and wma files which I know they contain an ac3 5.1 playback.Are you sure you didn't create them with TWO channel .AC3?

[Skunkmaster]

yes those are bluray backups some with 5.1 ac3 some with DTS.
the problem is that instead of passthrough the ac3filter gets it as non dolby digital nor dts but as regular stereo.
I tried to play them with my xbox 360 and the receiver got the signal well but my computer doesn't.