CODEWITHSUNDEEP
image-processingpython-3.xbinary
Dakeyras
Dakeyras

Reputation: 2251

Using Python to read and edit bitmaps

I need to read a bitmap image file (.bmp) and split the binary data into an array of bytes, which I can then reconstitute into the original file. Eventually, I will be modifying part of each byte to store data and then reading it to get the data back.

Details

Currently, I am using

file = open("example.bmp","rb")

data = file.read()

file.close()

to get the data. However, this is rather slow and inefficient. Next I want to split it into a byte array, and change the last bit to 0 for each bit that is not part of the metadata (I will use if statements to subtract 1 from each odd byte). Then I will re-merge the data, and save it into a new image file with the following code:

file = open("example2.bmp","wb")

file.write(data)

file.close()

although I suspect this may be sub-optimal too.

I need to know how to split a lot of binary data into bytes.

Upvotes: 4

Views: 18444

Answers (1)

Brent Washburne
Brent Washburne

Reputation: 13158

data is already a byte array, which you can index with slice notation. For example, according to the BMP file format, the Bitmap File Header is in data[0:14]. You may want to instead use C libraries in Python to save yourself some time.

Upvotes: 5

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