On 08/06/2012 06:25 PM, Roger Pack wrote: >> i may be wrong but "-r 1500" might do it > you could extract to images then select every 1500'th image. > -vf select='not(mod(n\,15))' > > might be helpful, too. "n" is frame number I...think... > -r > This one looks interesting! Will try. Thanks, Pb