Fading out the audio in a video

So I downloaded this video where it has 2 audio’s playing at once. So one in english which sounds like the background of the video and the overlapping russian audio. I want to fade out the russian audio out of the video.
How do I go about this? It’s basically a english video which has been translated into russian but I can still here the english in the video, and only want that part.
Answer #1
Have a look with Mediainfo and see if it has two separate audio tracks…
If it has ,you could demux it and then remux it using only the English audio using the apps in MKVToolnix.(for mkv)
http://forums.afterdawn.com/thread_view.cfm/510996
http://mediainfo.sourceforge.net/en
Paste the text output of Mediainfo here if you are not sure..
Answer #2
yeah I’m not sure so here it is:
complete name : C:\avi
Format : AVI
Format/Info : Audio Video Interleave
File size : 476 MiB
Duration : 49mn 42s
Overall bit rate : 1 340 Kbps
Video
ID : 0
Format : MPEG-4 Visual
Format profile : Simple@L1
Format settings, BVOP : No
Format settings, QPel : No
Format settings, GMC : No warppoints
Format settings, Matrix : Default (H.263)
Codec ID : DIVX
Codec ID/Info : Project Mayo
Codec ID/Hint : DivX 4
Duration : 49mn 42s
Bit rate : 1 199 Kbps
Width : 720 pixels
Height : 576 pixels
Display aspect ratio : 4:3
Frame rate: 25.000 fps
Standard : PAL
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Compression mode : Lossy
Bits/(Pixel*Frame) : 0.116
Stream size : 426 MiB (89%)
Writing library : avc2.0.11.1110
Audio
ID : 1
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 3
Mode : Joint stereo
Mode extension : MS Stereo
Codec ID : 55
Codec ID/Hint : MP3
Duration : 49mn 42s
Bit rate mode : Constant
Bit rate : 128 Kbps
Channel(s): 2 channels
Sampling rate : 48.0 KHz
Compression mode : Lossy
Stream size : 45.5 MiB (10%)
Alignment : Aligned on interleaves
Interleave, duration : 24 ms (0.60 video frame)
Answer #3
Only one audio track, so I guess the audio has all been mixed up together, so not much you can do unless you were lucky enough to find one in the left channel and the other in the right!