Split A4 PDF page into two A5 and back again

Question

I have a PDF with A4 pages. Each page contains two identical A5 pages for printing reasons. What I want to do in my Java program is to split these pages and use each unique

Answer 1

A possibly less clunky solution for the record, using pdfjam-related bits. If test.pdf is an A4 landscape doc to be split into A5 portrait:

1) extract left half-pages

pdfcrop --bbox "0 0 421 595" --clip --papersize "a5" test.pdf test-left.pdf

Note: --bbox " " works in bp units

2) extract right half-pages:

pdfcrop --bbox "421 0 842 595" --clip --papersize "a5" test.pdf test-right.pdf

3) collate pages as desired, e.g.

pdfjoin test-left.pdf test-right.pdf "1" --outfile test-collated.pdf

4) reglue:

pdfnup --nup 2x1 test-collated.pdf --a4paper --outfile test-done.pdf