About PDF-417 barcodes in general

A PDF-417 Barcode is a set of black and white modules. Each codeword of a PDF-417 symbol is consists of 17 modules. One PDF-417 symbol contains several data codewords and several Reed-Solomon error correction codewords. Additionally the PDF-417 barcode contains start and stop patterns, and left and right row-indicators to make the orientation and the dimensions of symbol clear.