I am rather new to video processing and particularly new to SUPER, so please be clement (at least at first). ;)
Trying to get to grips with the possibilities of transcoding, I am experimenting with all kinds of settings, like bitrate, scalesize, sampling frequency, rotating and joining files etc. Sometimes results are OK, but many output files have no more sound, e.g. if I rotate a video 90° or if I encode a MOV video with a higher bitrate. Is there a general reason for the audio to get lost? A transgression of certain limits?

I could deliver a detailed example, but as it happens with many settings ...
Is there a general online guide somewhere for a greenhorn to study?

All hints much appreciated.