Multiple Subject Question, Replacing audio

[cocteau32]

Hi-
I have an episode of a TV show which has had the original music replaced with generic elevator muck.
It is only in the last 5 minutes of the ep that I want to make a change.
I have:

1. the original video (with generic audio) in AVI (but I also have original DVD).
2. a copy of the ep with the correct audio in lower quality AVI only (but which cuts off about 30 seconds before the end!)
3. an mp3 of the complete song which finishes the episode

What I have been trying to do is to meld all 3 elements together by replacing the last 45 seconds of #1 with portions of the audio from #2 and #3.
So far I can't find the right software to accomplish this. I've tried extracting the audio from #1 & #2 but Audacity doesn't seem to like it. Then, once I've done the editing, can I just use Virtual Dub to replace the section on #1?
I'm not too bothered about sound quality as I can always reduce the gain a bit.
Sorry if this is poorly explained but maybe someone out there would like a challenge.
As I will probably do this only once or twice, a freeware solution would be great, even if it means a few more steps.

[redwudz]

Not sure why Audacity 'doesn't seem to like it'? If you extracted the audio as a WAV using VirtualDub in full audio processing mode, Audacity should accept it. Then if you can slice and dice the file and save it out as a MP3 or whatever format you need, and mux it back with the video, should work. But it's not uncommon that those different audio files may have different durations and sync may be a major problem.

And welcome to our forums.

EDIT: And cocteau32, in the future please use a more descriptive subject title in your posts to allow others to search for similar topics. I will change yours this time. From our rules:

Try to choose a subject that describes your topic.
Please do not use topic subjects like Help me!!! or Problems.

Thanks,
Moderator redwudz

[cocteau32]

Thank you for the welcome.
I may have solved the problem after all; it seems that I needed an FFmpeg library in order for Audacity to import the WAV file.
Before this, even when it loaded, all I could get was white noise.
It seems to have loaded now...
Do I use VirtualDub or VirtualDub Mod to mux the audio back onto the AVI file?
Could you give me a quick tutorial?

[redwudz]

I usually open the file in VD Mod, then save out as a WAV with full processing, then open that in Audacity. Never had to install ffmpeg for that, but I have it installed anyway. I leave VDM open, process the file with Audacity, then save out as mp3 most times, then add it back in, then save both the audio and video with Direct stream processing. Only takes a few minutes.

I use VD Mod more often as I like the way the audio settings are laid out. Just use 'Add' in the audio selection window and select the Audacity file, move the new file to the top, select and delete the old one. Click OK, then save the muxed file. This won't damage the original file unless you save with the same name and overwrite it. I'd play it first before closing VDM using VLC or MPC as VDM isn't a good player.

I use WAV format most times as some files are VBR audio and VDM doesn't like them. WAV fixes the problem.