Using digital x-ray imaging during silicon carbide (SiC) physical vapor transport process the SiC crystal growth as well as SiC powder source degradation have been monitored online. Using digital image processing we have (i) extracted from the x-ray shots the shape of the crystal growth interface, (ii) determined the crystal growth rate and (iii) analyzed the evolution of the SiC source material by determining its density as a function of progressing process time. The underlying sublimation and crystallization effects are discussed.