renaming files

[Bill]

Hi,

I am trying to make a video from jpg files.  The files are in the 
correct order but there are gaps in the sequence and the sequence should 
start at 1.  This can be done manually but this is both tedious and 
error prone.  Is there a utility that does this.  I tried PyRenamer but 
it seems that this doesn't  do what I want.

example:

before:  test 5, test 6, test 7,  test 10, test 20

these files should be renamed as

after:    test 1, test 2, test 3,  test 4, test 5

Thanks for any hints