Synopsis
		sffourvc < in.rsf > out.rsf eps=0.01 pad=n1 pad2=2*kiss_fft_next_fast_size((n2+1)/2) verb=n nv= dv= extend=4 v0=

Parameters
		float dv= velocity step size   float eps=0.01 regularization   int extend=4 trace extension   int nv= velocity steps   int pad=n1 padding for stretch   int pad2=2*kiss_fft_next_fast_size((n2+1)/2) padding for FFT   float v0= starting velocity   bool verb=n [y/n] verbosity flag