Record varying resolution videos simultaneously with one webcam

Question

I am trying to create 2 recordings at the same time from one webcam. A low resolution video that i can use to train a neural network, and a higher resolution video for me to label data for my training. Does anyone know of any software i can use to do this that is light enough to be run on a raspberry Pi?

Answer 1

You can do this using python's opencv. See snippet below.

import cv2
import numpy as np

# Create a VideoCapture object
cap = cv2.VideoCapture(0)

# Check if camera opened successfully
if (cap.isOpened() == False): 
  print("Unable to read camera feed")

# Default resolutions of the frame are obtained.The default resolutions are system dependent.
# We convert the resolutions from float to integer.
frame_width = int(cap.get(3))
frame_height = int(cap.get(4))

# Define the codec and create VideoWriter object.The output is stored in 'outpy.avi' file.
out = cv2.VideoWriter('output1.avi',cv2.VideoWriter_fourcc('M','J','P','G'), 10, (frame_width,frame_height))
out2 = cv2.VideoWriter('output2.avi',cv2.VideoWriter_fourcc('M','J','P','G'), 10, (640,480))

while(True):
  ret, frame = cap.read()

  if ret == True: 

    # Write the frame into the file 'output.avi'
    out.write(frame)
    out2.write(frame)

    # Display the resulting frame    
    cv2.imshow('frame',frame)

    # Press Q on keyboard to stop recording
    if cv2.waitKey(1) & 0xFF == ord('q'):
      break

  # Break the loop
  else:
    break 

# When everything done, release the video capture and video write objects
cap.release()
out.release()
out2.release()

# Closes all the frames
cv2.destroyAllWindows()