FFMPEG audio question

[DDF]

Is there any way you can do a ffmpeg conversion of a file containing several audio tracks..(2.0 on track 1+2, 5.1 on 3,4,5,6,7,8 etc.. and specify which tracks to use in the conversion.. AND down-mix them as a multiplex track. So 1&2 is one stereo track... and 3,4,5,6,7,8 is one multiplex track.

Help MUCH appreciated

Best,
Peter

[ProWo]

Post a mediainfo report (text mode) from your file here.

[pandy]

You can select each audio track separately by using numeric descriptor e.g. '-c:a:0?' (recommends to add '?' mark for higher script flexibility) combined with '-map 0:xx?' and '-filter_complex' (if there is difference between number of inputs and outputs).
This can be bit tricky so you need to prepare for some learning effort