let name = format!("assets/{}out{:02}_{:06}.ppm", pfx, strno, num);
let mut ofile = File::create(name).unwrap();
if let NABufferType::VideoPacked(ref buf) = frm.get_buffer() {
let name = format!("assets/{}out{:02}_{:06}.ppm", pfx, strno, num);
let mut ofile = File::create(name).unwrap();
if let NABufferType::VideoPacked(ref buf) = frm.get_buffer() {