Planned flags:

--level LEVEL_NUMBER

From 1 to 10, ouch should "translate" that range for each format, considering that some formats use higher numbers than others.

--fast

Less intensive compressing, we can seek for the best defaults aiming for 50% of time taken (run in half the time).

--slow

More intensive compressing, takes longer, we shall look for defaults that take up to double the time, but also, we'll need to establish a RAM limit.

Some compression methods have a memory usage table that explains how much a certain level can use.