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pythonopencvjpeg

python OpenCV jpeg compression in memory


In OpenCV it is possible to save an image to disk with a certain jpeg compression. Is there also a way to do this in memory? Or should I write a function using cv2.imsave() that loads the file and removes it again from disk? If anyone knows a better way that is also fine.

The use case is real-time data augmentation. Using something else than OpenCV would cause possibly unnecessary overhead.

Example of desired function im = cv2.imjpgcompress(90)


Solution

  • You can use imencode:

    encode_param = [int(cv2.IMWRITE_JPEG_QUALITY), 90]
    result, encimg = cv2.imencode('.jpg', img, encode_param)
    

    (The default value for IMWRITE_JPEG_QUALITY is 95.)

    You can decode it back with:

    decimg = cv2.imdecode(encimg, 1)
    

    Snippet from here