Save a bitstream to a file using python

Question

I need to output an h.265 (or hevc, is the same) bit-stream onto an str file in python.

I have a bitstream file and i select some data from this file to save it to a new one. I use bitstring module to process the bitstream file.

Edit: My question is how to create a new bitstream file and insert data into.

Please show the code you have, and what part is causing you problems. — , Sep 18 '14 at 13:47
Why not just open the file as binary and do `struct.pack` to pack characters, etc. into binary? — Chrispresso, Sep 18 '14 at 13:59

score 1 · Answer 1 · answered Sep 18 '14 at 14:53

1

Take a look at struct

A quick example:

import struct
characters = "Hello World"
with open(filepath, 'wb') as f:
    for char in characters:
        # @B means to pack native (LSB or MSB) to size unsigned char (1 byte)
        packed = struct.pack('@B', char)
        f.write(packed)

answered Sep 18 '14 at 14:53

Chrispresso

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Thank you but I find it easier to use the solution above. – zinon Sep 19 '14 at 10:25

score 1 · Accepted Answer · answered Sep 19 '14 at 08:22

Check out the part about Joining BitArrays (base class of BitStream) in this part of the bitstring documentation. How to join the substreams depends on how you have them in the first place.

For writing the bitstream to a file, use the method 'toFile' of the Bits class, which is a base class of BitStream.

f = open('fileToWriteTo', 'wb')
bitstreamObject.tofile(f)

If you want to write multiple substreams one after another, you can open the file in append mode the next times you write something.

f = open('fileToWriteTo', 'ab')
nextSubstream.tofile(f)

Save a bitstream to a file using python

2 Answers2