Searching/reading binary data in Python

Question

I\'m reading in a binary file (a jpg in this case), and need to find some values in that file. For those interested, the binary file is a jpg and I\'m attempting to pick out

Answer 1

The bitstring module was designed for pretty much this purpose. For your case the following code (which I haven't tested) should help illustrate:

from bitstring import ConstBitStream
# Can initialise from files, bytes, etc.
s = ConstBitStream(filename='your_file')
# Search to Start of Frame 0 code on byte boundary
found = s.find('0xffc0', bytealigned=True)
if found:
    print("Found start code at byte offset %d." % found[0])
    s0f0, length, bitdepth, height, width = s.readlist('hex:16, uint:16, 
                                                        uint:8, 2*uint:16')
    print("Width %d, Height %d" % (width, height))