encoding 1080p wmv9 + 6ch wma wmv to 480p x264 + 6ch aac mp4

[chros]

I have tried to encode (with the help of megui) this trailer (it's a self-extracting exe, no drm, 1:53, 126MB) from microsoft, but I have 3 problems:

1. video duration
I have used this script (in MPC the decoders are: WMVideo decoder DMO and WMAudio decoder DMO ):

DirectShowSource("Alexander_Trailer_1080p.wmv", audio=False, fps=23.976)
crop( 0, 132, 0, -132)
LanczosResize(848,352)

In this case at the end of the resulted mp4 is a repeated section of the trailer (the end). It's like avisynth knows the duration (1:53), but the encoded frames are much less and then it repeats a section to correct the duration.

If I'm using the convertfps=true parameter too (to dssource function), then there are freezed frames: like avisynth adds still frames to get the correct duration.

If I'm using the seek=false parameter too, then I get a video as in the 1st case, but not repeated section in the end: so the duration is about 1:38 ...

(Of course the original wmv is perfectly played in MPC)

I have tried to create a graph with graphedit, like this:

file  -->  WMVideo Decoder DMO

No changes in the results (both 3 cases).
And I also tried to change the WMVideo DMO to ffdshow in the graph (enabling wmv3/wmv9 decodeing): resulting the same ...

So what can be the problem, and how can I get rid of that?

2. washed out colors
It's like when I switch from Overlay to VMR7 in MPC.
Can I do about it something or the original encode is just simlpy bad.

3. couldn't convert 6ch audio
2 channel works fine, but 6ch doesn't.
In MPC AC3filter connects to WMAudio DMO and results 6ch audio, but when I create the same graph it's only 2 channel. Strange ...

file  --> WMAudio DMO  -->  AC3filter

I have removed AC3 filter from the graph, but it resulted only 2ch.
I checked the PIN out0 info of WMAudio DMO in MPC:

- Connection media type:
Audio: WAVE_FORMAT_EXTENSIBLE 48000Hz 6ch 6912Kbps
...
- Enumerated media type 1:
Audio: WAVE_FORMAT_EXTENSIBLE 48000Hz stereo 2304Kbps
...
- Enumerated media type 2:
Audio: PCM 48000Hz stereo 1536Kbps

So what does it mean?
Is it means that the decoder can produces different outputs?
If it is, then in MPC AC3 filter can connect to 6ch waveformat_ex but not in graphedit ... Strange ...

Any idea ?
Thanks