Trying to record "time true" video with openCV. When recording video footage it seems to be slightly sped up. If I hold a timer up to the webcam and then play it back saved footage is 3 - 5 seconds too fast per minute of saved footage.
How can I get the saved video to be exactly 1 minute if I record 1 minute from my webcam? Or 2 minutes of recording to be an exported 2-minute video?
import cv2
cap = cv2.VideoCapture(0)
fps = cap.get(cv2.CAP_PROP_FPS)
cap.set(cv2.CAP_PROP_FRAME_WIDTH, 640)
cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 480)
width = cap.get(cv2.CAP_PROP_FRAME_WIDTH) # float `width`
height = cap.get(cv2.CAP_PROP_FRAME_HEIGHT) # float `height`
fourcc = cv2.VideoWriter_fourcc(*'XVID')
videoWriter = cv2.VideoWriter('MYPATH\\video.avi', fourcc, fps, (int(width),int(height)))
while (True):
ret, frame = cap.read()
if ret:
cv2.imshow('video', frame)
videoWriter.write(frame)
if cv2.waitKey(1) == 27:
break
cap.release()
videoWriter.release()
cv2.destroyAllWindows()
I have no idea why this fixed it... but changing the forcc to fourcc = cv2.VideoWriter_fourcc(*'MP4V') and then changing the output file from .avi to .mp4 fixed the problem.
Your program may write additional frames because True sentence at line 16 in your while loop, then change that value to check as conditional ret, by:
...
ret, frame = cap.read()
while (ret):
cv2.imshow('video', frame)
videoWriter.write(frame)
ret, frame = cap.read()
if cv2.waitKey(1) == 27:
break
cap.release()
videoWriter.release()
cv2.destroyAllWindows()
Related
How to record video rtsp and save video for 5 minutes using python and opencv
i m using to record some of the code but for 5 minutes using clas and function video is very tuff to download for 5 minutes.
You will need to import cv2. You may need to execute pip install opencv-python to install the module for importation.
import cv2
import time
# open video stream
cap = cv2.VideoCapture('rtsp://127.0.0.1/stream')
# set video resolution
cap.set(3, 640)
cap.set(4, 480)
# set video codec
fourcc = cv2.VideoWriter_fourcc(*'XVID')
out = cv2.VideoWriter('output.avi', fourcc, 20.0, (640, 480))
# start timer
start_time = time.time()
while (int(time.time() - start_time) < 300):
ret, frame = cap.read()
if ret == True:
out.write(frame)
cv2.imshow('frame', frame)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
else:
break
# release resources
cap.release()
out.release()
cv2.destroyAllWindows()
Using OpenCV, I have been extracting the frames from a video and after working on the frames, I have been trying to save them to a new video file. But the new video file is not being saved properly. It gets saved as 0 KB in size and throws the following error when I try to open it.
OpenCV Error
My code is as follows:
import cv2
cap = cv2.VideoCapture("Path to source video")
out = cv2.VideoWriter("Path to save video", cv2.VideoWriter_fourcc(*"VIDX"), 5, (1000, 1200))
print(cap.isOpened())
while True:
# Capture frame-by-frame
ret, frame = cap.read()
# Write the video
out.write(frame)
# Display the resulting frame
cv2.imshow('frame',frame)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
cap.release()
out.release()
cv2.destroyAllWindows()
I tried to follow the solution Can't save a video in opencv but it did not help in my case.
when saving the file, your width and height should match with frame's width and height, so in order to get the width and height of the frame automatically, use
import cv2
cap = cv2.VideoCapture(0)
width = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH)) # to get width of the frame
height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT)) # to get height of the frame
out = cv2.VideoWriter("dummy_video.mp4", cv2.VideoWriter_fourcc(*"VIDX"), 5, (width, height))
print(cap.isOpened())
while True:
# Capture frame-by-frame
ret, frame = cap.read()
# Write the video
out.write(frame)
# Display the resulting frame
cv2.imshow('frame',frame)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
cap.release()
out.release()
cv2.destroyAllWindows()
Used: OpenCV and Python3
I am using Python 3.8.2
Operating System: macOS Big Sur 11.2.3
I tried this code on VScode, it does show a video with changed speed with the cv2.imshow command but I don't know how to save that changed video in my folder:
import cv2
cap = cv2.VideoCapture('Pothole testing.mp4')
frameTime = 100
while(cap.isOpened()):
ret, frame = cap.read()
cv2.imshow('frame',frame)
if cv2.waitKey(frameTime) & 0xFF == ord('q'):
break
cap.release()
cv2.destroyAllWindows()
Can anyone tell me what should I add to this code so that the changed video gets saved? And preferably in the .mp4 format itself.
You can use the fps parameter of the cv2.VideoWriter() method. The fps can be calculated by simple diving your frameTime variable by 1000, as the cv2.waitKey() method takes in a number and uses it as a thousandth of a second.
Note that if the cap never closed during the while loop, the while cap.isOpened() won't be any better than while True, meaning by the time the last frame is read, an error would occur, causing the writer.release() method to never be called, thus making the resulting file unreadable.
Here is how I would do it:
import cv2
cap = cv2.VideoCapture('Pothole testing.mp4')
ret, frame = cap.read() # Get one ret and frame
h, w, _ = frame.shape # Use frame to get width and height
frameTime = 100
fourcc = cv2.VideoWriter_fourcc(*"XVID") # XVID is the ID, can be changed to anything
fps = 1000 / frameTime # Calculate fps
writer = cv2.VideoWriter("Pothole testing 2.mp4", fourcc, fps, (w, h)) # Video writing device
while ret: # Use the ret to determin end of video
writer.write(frame) # Write frame
cv2.imshow("frame", frame)
if cv2.waitKey(frameTime) & 0xFF == ord('q'):
break
ret, frame = cap.read()
writer.release()
cap.release()
cv2.destroyAllWindows()
If all you need is the resulting file and not the progress window, you can omit a few lines:
import cv2
cap = cv2.VideoCapture('Pothole testing.mp4')
ret, frame = cap.read()
h, w, _ = frame.shape
frameTime = 100
fourcc = cv2.VideoWriter_fourcc(*"XVID")
fps = 1000 / frameTime
writer = cv2.VideoWriter("Pothole testing 2.mp4", fourcc, fps, (w, h))
while ret:
writer.write(frame)
ret, frame = cap.read()
writer.release()
cap.release()
I want to write a video using OpenCv and process every frames in different seconds.
I am using cv2.VideoWriter, but the output file shows only the first frame of my video and it is not playing. I wanted to add text on the first frame and it did it, but it doesn't continue with the rest of the video.
As you can see from the code below, it creates a new output file for the new processed video.
It does create the mp4 file, but only showing first frame with the added text and it is not playing.
Any suggestion why this is happening?
Here is my code, I am using Spyder and windows.
fps = int(round(cap.get(5)))
frame_width = int(cap.get(3))
frame_height = int(cap.get(4))
fourcc = cv2.VideoWriter_fourcc(*'mp4v')
out = cv2.VideoWriter(output_video_file,fourcc,fps,(frame_width,frame_height))
while(True):
# Capture frame-by-frame
ret, frame = cap.read()
if ret:
if cv2.waitKey(28) & 0xFF == ord('q'):
break
if between(cap, 0, 10000):
font = cv2.FONT_HERSHEY_COMPLEX_SMALL
cv2.putText(frame,'hello',org=(10,600),fontFace=font,fontScale=10,color=(255,0,0),thickness=4)
pass
# Our operations on the frame come here
out.write(frame)
# Display the resulting frame
cv2.imshow('frame',frame)
Exactly I could not find the problem in your code because you did not give the between function. However you may try following snippet:
import cv2
import numpy as np
cap = cv2.VideoCapture(0)
if (cap.isOpened() == False):
print("Unable to read camera feed")
frame_width = int(cap.get(3))
frame_height = int(cap.get(4))
fps = int(round(cap.get(5)))
out = cv2.VideoWriter('output.mp4', cv2.VideoWriter_fourcc(*'mp4v'), fps, (frame_width, frame_height))
while (True):
ret, frame = cap.read()
if ret == True:
cv2.putText(frame, 'hello',
org=(10, 300),
fontFace=cv2.FONT_HERSHEY_SIMPLEX,
fontScale=5,
color=(255, 0, 0),
thickness=4)
out.write(frame)
cv2.imshow('frame', frame)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
else:
break
cap.release()
out.release()
cv2.destroyAllWindows()
I have taken the following code from this website.
import cv2
cap = cv2.VideoCapture(0)
# Define the codec and create VideoWriter object
fourcc = cv2.VideoWriter_fourcc(*'avc1')
out = cv2.VideoWriter('output.avi', fourcc, 20.0, (640, 480))
while cap.isOpened():
ret, frame = cap.read()
if ret:
out.write(frame)
cv2.imshow('Video', frame)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
else:
break
# Release everything if job is finished
cap.release()
out.release()
cv2.destroyAllWindows()
The problem I am facing is that the video is being stored, but I am not able to open it. The video size is about 6KB, but the duration is 0 seconds. How can I fix this?
I did check the other questions similar to this, but none of them solve the issue I am facing.
I had problem with opening file if I saved frames with wrong size.
If camera gives frame with size ie. (800, 600) then you have to write with the same size (800, 600) or you have to use CV to resize frame to (640, 480) before you save it.
frame = cv2.resize(frame, (640, 480))
Full code
import cv2
cap = cv2.VideoCapture(0)
# Define the codec and create VideoWriter object
fourcc = cv2.VideoWriter_fourcc(*'avc1') #(*'MP42')
out = cv2.VideoWriter('output.avi', fourcc, 20.0, (640, 480))
while cap.isOpened():
ret, frame = cap.read()
if ret:
frame = cv2.resize(frame, (640, 480))
out.write(frame)
cv2.imshow('Video', frame)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
else:
break
# Release everything if job is finished
cap.release()
out.release()
cv2.destroyAllWindows()
Example on GitHub: furas/python-examples/cv2/record-file
One thing that I found out after much googling was that the VideoWriter fails silently.
In my case, I didn't have a VideoCapture object, but a list of frames. I followed the guide similar to what you have done, but the problem was that I was passing in the shapes of the array according to what img.shape[:2] was giving me. IIRC, OpenCV has a different ordering of the widths and heights than numpy arrays do which was the source of my problem. See below for the comment from here
As have been stated by #pstch, when creating VideoWriter in Python one should pass frame dimensions in form cv.VideoWriter(filename, fourcc, fps, (w, h), ...). And when creating frame itself - in reverse order: frame = np.zeros((h, w), ...)