Linearized PDF is a version of the PDF format in which the data is held in a special manner to allow content to be fetched only when needed. This means viewing a multipage PDF over a slow connection is more responsive. By default, cpdf does not linearize output files. To make it do so, add the -l option to the command line, in addition to any other command being used. For example:
cpdf -l in.pdf -o out.pdf
Linearize the file in.pdf, writing to out.pdf.