CODEWITHSUNDEEP
pythonopencvframe
kylel95
kylel95

Reputation: 139

How to solve OverflowError: Python int too large to convert to C long with opencv?

__author__ = 'Kyle'

HELP_MESSAGE = """Script: frame_grabber.py
Usage: python frame_grabber.py path/to/video
Requires: OpenCV 2.4.8+
Purpose: Select and save frames from a given video.
   Commands:
   Key             Function
   a               previous frame
   d               next frame
   q               exit
   SHIFT + a       skip 10 frames forward
   SHIFT + d       skip 10 frames backwards
   s               saves current frame
   dbl click       saves current frame
Controls:
Slider          Navigate through the video
"""

# Check if the user has provided a path to a file
# otherwise display the HELP_MESSAGE

import sys
import time as t

# Check if OpenCV module is present
# otherwise stop the application

try:
    import cv2
except ImportError as e:
    print "Fatal Error: Could not import OpenCV, ", e
   exit(-1)
else:
    print "Using OpenCV ", cv2.__version__

# these flags may depend on your opencv version:
# in opencv 3.0.0 these flags are implemented as
# cv2.CAP_PROP_POS_FRAMES and
# cv2.CAP_PROP_FRAME_COUNT

CURRENT_FRAME_FLAG = cv2.cv.CV_CAP_PROP_POS_FRAMES
TOTAL_FRAMES_FLAG = cv2.cv.CV_CAP_PROP_FRAME_COUNT
WIN_NAME = "Frame Grabber"
POS_TRACKBAR = "pos_trackbar"

#VIDEO_PATH = 'camera13.h264'

  #try:
  #   VIDEO_PATH = sys.argv[1]
  # except IndexError as e:
  #   print HELP_MESSAGE
  #  exit(-1)


    cap = cv2.VideoCapture("camera13.h264")

    if not cap.isOpened():
        print "Fatal Error: Could not open the specified file."
        exit(-1)

ret, frame = cap.read()

if not ret:
    print "Fatal Error: Could not read/decode frames from specified file."
    exit(-1)


def dummy():
    pass


def save_image():
    filename = "image_%0.5f.png" % t.time()
    cv2.imwrite(filename, frame)


def seek_callback(x):
    global frame
    i = cv2.getTrackbarPos(POS_TRACKBAR, WIN_NAME)
    cap.set(CURRENT_FRAME_FLAG, i-1)
    _, frame = cap.read()
    cv2.imshow(WIN_NAME, frame)


def mouse_callback(event,x,y,flags,param):

if event == cv2.EVENT_LBUTTONDBLCLK:
    save_image()


 def skip_frame_generator(df):

     def skip_frame():
          global frame
          cf = cap.get(CURRENT_FRAME_FLAG) - 1
          cap.set(CURRENT_FRAME_FLAG, cf+df)
          cv2.setTrackbarPos(POS_TRACKBAR, WIN_NAME,                  int(cap.get(CURRENT_FRAME_FLAG)))
          _, frame = cap.read()

return skip_frame


cv2.namedWindow(WIN_NAME)
cv2.createTrackbar(POS_TRACKBAR, WIN_NAME, 0,             int(cap.get(TOTAL_FRAMES_FLAG)), seek_callback)
cv2.setMouseCallback(WIN_NAME, mouse_callback)

 actions = dict()

actions[ord("D")] = skip_frame_generator(10)
actions[ord("d")] = skip_frame_generator(1)
actions[ord("a")] = skip_frame_generator(-1)
actions[ord("A")] = skip_frame_generator(-10)
actions[ord("q")] = lambda: exit(0)
actions[ord("s")] = save_image

while True:

    cv2.imshow(WIN_NAME, frame)
    key = cv2.waitKey(0) & 0xFF
    actions.get(key, dummy)()``

When the code is executed, I receive the error - OverflowError: Python int too large to convert to C long. How may I go about solving this please? This code is meant to create a frame grabber that allows me to pick a frame that I want and save it.

Upvotes: 0

Views: 1880

Answers (1)

SiHa
SiHa

Reputation: 8421

Well, the error is telling you that you are passing a number in this line: 

cv2.createTrackbar(POS_TRACKBAR, WIN_NAME, 0,int(cap.get(TOTAL_FRAMES_FLAG)), seek_callback)

That is too large to be cast to ctypes.c_long; The maximum number that can be represented by this type is (2**31)-1 = 2147483647.

This is presumably your TOTAL_FRAMES_FLAG. Now that's a lot of frames (approx. 500 days @50fps), so it can't be right.

I notice that you are getting this value before you open the video file, so it's likely to be undefined at that point. Try doing it after you've opened your file, and see if that fixes things. You could print the value, as well, to see if it is indeed too large (before you try the suggested change).

Upvotes: 1

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