I have a clarification, an inverter converts DC to AC using for example SPWM, but can the DC input be as below
or it should only be a straight line?

 

Cycloconverters do take the rectified waveform that you show, but the resultant output can only be a integer sub harmonic of the input frequency.
Otherwise, it has to be straight line DC, or with a low ripple.

 

I have a clarification, an inverter converts DC to AC using for example SPWM, but can the DC input be as below
View attachment 367954or it should only be a straight line?

Just add suitably sized capacitor and it will, presuming that it was created by rectifying AC. If not, you would need a diode as well.