Is there any generic binary protocol codec library for python?

Question

There is nice one for java - MINA.

Once I've heard that there is something similar for python. But can't remind.

EDIT: to be more specific, I would like to have a tool which would help me to create a coded for some binary stream.

EDIT2: I'd like to list solutions here (thanks Scott for related topics) Listed in order i'd use it.

bitstring (great documentation, which i'll choose)
hachoir
BitVector (to cryptic at the first glance)
bitarray
struct (python std)
bitmanipulation tut

Some possibly related questions: stackoverflow.com/questions/39663 stackoverflow.com/questions/967652 — Scott Griffiths
– Scott Griffiths, Commented Aug 18, 2010 at 11:19
Another related question: stackoverflow.com/questions/3753589/… — Victor Sergienko
– Victor Sergienko, Commented Dec 8, 2020 at 23:59

Scott Griffiths · Accepted Answer · 2011-01-24 13:26:48Z

5

Have you tried the bitstring module? (Full disclosure: I wrote it).

It's designed to make constructing and parsing binary data as simple as possible. Take a look at a few examples to see if it's anything like you need.

This snippet does some parsing of a H.264 video file:

    from bitstring import ConstBitStream
    s = ConstBitStream(filename='somefile.h264')
    profile_idc = s.read('uint:8')
    # Multiple reads in one go returns a list:
    constraint_flags = s.readlist('4*uint:1')
    reserved_zero_4bits = s.read('bin:4')
    level_idc = s.read('uint:8')
    seq_parameter_set_id = s.read('ue')
    if profile_idc in [100, 110, 122, 244, 44, 83, 86]:
        chroma_format_idc = s.read('ue')
        if chroma_format_idc == 3:
            separate_colour_plane_flag = s.read('uint:1')
        bit_depth_luma_minus8 = s.read('ue')
        bit_depth_chroma_minus8 = s.read('ue')
        ...

edited Jan 24, 2011 at 13:26

answered Aug 18, 2010 at 11:26

Scott Griffiths

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4 Comments

Andrew Over a year ago

Looks like an interesting library. I'm going to have a more extensive play with it when I find some time.

slhck Over a year ago

Actually, the bitstream should be split into NAL units prefixed with with 0x000001 or 0x00000001 start codes. Your code shows how to parse an SPS directly. How would I translate this with your library?

Scott Griffiths Over a year ago

@slhck: Well start by searching for a byte aligned 0x000001. s.find('0x000001', bytealigned=True). But I couldn't really write a full H.264 decoder in a S.O. answer so it was only meant to be illustrative.

slhck Over a year ago

Sure :) thanks, I found what I needed. What I meant to say is that I think the code as presented will probably not work because there should be at least a 0x00 00 00 prefix in the file at the very beginning.

Nikolaus Gradwohl · Accepted Answer · 2010-08-18 10:49:33Z

5

python has pack/unpack in the standard lib that can be used to interpret binary data and map them to structs

see "11.3. Working with Binary Data Record Layouts" here http://docs.python.org/tutorial/stdlib2.html

or here http://docs.python.org/library/struct.html

answered Aug 18, 2010 at 10:49

Nikolaus Gradwohl

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