let name = format!("{}out{:02}_{:08}.ppm", pfx, strno, num);
let mut ofile = File::create(name).unwrap();
if let NABufferType::VideoPacked(ref buf) = frm.get_buffer() {
let name = format!("{}out{:02}_{:08}.ppm", pfx, strno, num);
let mut ofile = File::create(name).unwrap();
if let NABufferType::VideoPacked(ref buf) = frm.get_buffer() {