Enhancement Opus compression_level and qscale

[artofit]

For the sake of standardisation, would welcome

ffmpeg -i input.wav -c:a libopus -q:a 5 ouput.mkv

instead of currently

ffmpeg -i input.wav -c:a libopus -compression_level 5 ouput.mkv

This already applies to other audio codec such as mp3 or aac.

Ref:

​http://trac.ffmpeg.org/wiki/Encoding%20VBR%20%28Variable%20Bit%20Rate%29%20mp3%20audio

​http://trac.ffmpeg.org/wiki/AACEncodingGuide

[redneb]

I don't think mapping comp to the -q flag is a good idea: comp refers to the encoding computational complexity (i.e. encoder speed), not the audio quality. So this like the lame -q flag (which ffmpeg maps to -compression_level) and not the -V lame flag (which ffmpeg maps to -q). So I think the current mapping of comp to -compression_level is correct and consistent with other lossy audio codecs. I believe this issue can be marked as invalid.