Demuxing mixed 2.0/5.1 channel audio from TS

[uheuheuhe]

I have a standard mpeg2 TS file acquired from a firewire source, and the beginning of the file has 2.0 AC3 audio, for about 20 seconds, and then the entire rest of the file has 5.1 audio. My ultimate goal is to be able to import this video, as well as each discrete audio channel, into Sony Vegas (I have 8 Pro). My problem is that no matter how I try to demux the audio, it is always detected as stereo only. I have tried demuxing with dgindex as well as virtualdub, and I have even tried cutting out the 2.0-only beginning section of the video with murdoc cutter, but it produces no different results. Vegas, MPC, and VLC all detect the demuxed audio as 2.0, *but* VLC can play the original file just fine, switching into 5.1 mode at the correct time (but a demuxed audio file still only plays as stereo). Any ideas would be appreciated. Thanks

[tebasuna51]

Cut the demuxed ac3 with DelayCut.

A first step show you the frame change, like this:
Time 00:00:00.160; Frame#= 6. Some basic parameters changed between Frame #1 and this frame

then cut using a Delay of -160 ms (in this sample)

[streaming machines]

Apparently it sounds that the demultiplexers you used support only stereo thats why the output is stereo only in every case. Many demultiplexers are commercially available which support 5.1 channel audio.