Demux the audio with VirtualDubMod (optional)
Ok, you need to do this step if your video file contains an audio file that TMPGEnc doesn't support, such as AC3 or Ogg Vorbis. So, open the modified version of VirtualDub called VirtualDubMod and go to File menu and select Open video file... and locate your .avi file
Next, go to Audio menu and check that Direct stream copy is selected -- if not, select it. After you've done that, go to File menu again and select Save WAV....
This pops up a new dialog box. From Save as type: dropdown, select All files (*.*). Then enter an easy-to-remember filename for your audio with correct extension -- if your audio is in Ogg Vorbis, use extension .ogg or if your audio is in AC3, use extension .ac3 (you checked the audio compression with GSpot earlier on). Also make sure that your destination directory has at least couple of hundred megabytes of free space, since especially AC3 tends to take quite a lot space. Now, enter something as your filename and remember to use the file extension accordingly. Then click Save button.
Now VirtualDubMod is processing the AC3 and saving it into a separate file for further processing with audio encoders. This takes a while, but shouldn't take "forever".
Fix the AC3 or OGG audio file headers (optional)
Now, since VirtualDubMod tends to add WAV headers to the all audio files it demuxes by using "Save WAV" feature, we need to fix the file headers. We do this by using BeSliced which is basically just a very basic GUI for BeSplit -- which is included inside BeSliced's distribution package.
Launch BeSliced and you'll see a small window with a guy's face on it. That's everything there is :-) Don't try to find anything fancy from the tool, there isn't anything but the guy in there ;-)
Now, find your .ac3 or .ogg file (depends on your audio format you had in your AVI) and drag-n-drop it into BeSliced's window. This pops up a small menu with two options -- select the one that says Fix File!. This opens a good olde command prompt window with BeSplit running on it and fixing the file. After few moments, you'll see a short log file of errors found on the file and that's it -- the file has been fixed to have correct audio headers.
Written by: Petteri Pyyny