spamming about the export_null module

Hi again,

as per my previous email, the following command worked for audio extraction:

transcode -i /dev/dvd -x dvd -T 1,1,1 -a 1 -y null,tcaud -N 0x1 -m 
track1.pcm

but it seems to be wasting a lot of CPU in the tcdecode module for video 
signal, which is instead supposed to be driven by the "export_null" module

I was wondering, why is the video decoding process needed (consuming 
CPU) if the only thing we wanted (looking at the command line) is audio 
data?

thanks for clarifying :)