GFF/GTF: how to translate CDS genomic coordinates to protein coordinates

Question

[abascalfederico]

Hi,

Starting with a GENCODE GTF/GFF3 file I need to obtain the following information for each CDS entry in the GTF/GFF3 file: cds length (total for the protein), cds start (with respect to the protein, not the chromosome), and cds end.

Anyone knows of a tool to do this (and save me a lot of work implementing something)?

Many thanks! Federico