We have investigated the influence of the driving force and motion of the vortex lattice on the vortex depinning and dissipation in vibrating (Formula presented) superconducting films. At high enough driving force our results show a motional narrowing of the depinning transition. In this regime the temperature dependence of the energy dissipation can be quantitatively understood with the diffusion model without free parameters. Additionally, the simultaneous measurement of the vibrating superconductor with its (Formula presented) characteristics shows that the depinning temperature coincides with the so-called “glass” transition temperature. © 1999 The American Physical Society.