If your script is mpeg2source/ffvideosource/dss2, then you don't have the audio loaded in avisynth. If you need the audio, then you can load it like so:
Code: Select all
audiodub(mpeg2source("blabla.d2v"),wavsource("blabla.wav"))
Generally speaking you can try using ffaudiosource for any non wav audio. Failing that, a good alternative would be
bassaudiosource which does however require you to also have the dll for the format you need to open in the plugins directory. Another option is just loading the audio with directshowsource.
If you are loading with avisource and it still is giving you trouble, I suppose you can just try the "audio from other file" option. Also, keep in mind that Lame (at least in my experience) doesn't like when you try to compress your audio to a Hz amount different to the input. You might have exported your audio as 48000Hz and so trying to compress it as 44100Hz would fail.