Extract JPG from pdf

jpg_extract.py

import sys

with open("test.pdf", "rb") as f:
    pdf = f.read()

startmark = b"\xff\xd8"
startfix = 0
endmark = b"\xff\xd9"
endfix = 2
i = 0
njpg = 0

while True:
    istream = pdf.find(b"stream", i)
    if istream < 0:
        break
    istart = pdf.find(startmark, istream, istream+20)
    if istart < 0:
        i = istream+20
        continue
    iend = pdf.find(b"endstream", istart)
    if iend < 0:
        raise Exception("Didn't find end of stream!")
    iend = pdf.find(endmark, iend-20)
    if iend < 0:
        raise Exception("Didn't find end of JPG!")
    istart += startfix
    iend += endfix
    print("JPG %d from %d to %d" % (njpg, istart, iend))
    jpg = pdf[istart:iend]

    with open("jpg%d.jpg" % njpg, "wb") as f:
        f.write(jpg)
    njpg += 1
    i = iend