Develop Reference

Reading frames from Flask Server into PyCharm

from flask import Flask, Response, request, send_file
from moviepy.editor import VideoFileClip
import socket
import cv2 as cv2
app = Flask(__name__)
video_path = "videos/video.avi"
#app.route('/video_feed/')
def video_feed():
start_frame = int(request.args.get("start_frame"))
end_frame = int(request.args.get("end_frame"))
return Response(gen(start_frame, end_frame), mimetype='multipart/x-mixed-replace; boundary=frame')
def gen(start_frame, end_frame):
cap = cv2.VideoCapture(video_path)
cap.set(1, start_frame)
while True:
success, img = cap.read()
current_frame = cap.get(cv2.CAP_PROP_POS_FRAMES)
if current_frame > end_frame:
break
imgencode = cv2.imencode('.jpg', img)[1]
stringData = imgencode.tobytes()
# can also use tostring()
yield (b'--frame\r\n'
b'Content-Type: text/plain\r\n\r\n' + stringData + b'\r\n')
if __name__ == '__main__':
app.run(host='0.0.0.0', port=8000, debug=True)
So, this is the Flask server I am running. I am able to view the correct frames being yielded by the flask server at this URL: (It doesn't matter that the video playback is too fast)
http://127.0.0.1:8000/video_feed/?start_frame=0&end_frame=5000
But I can't seem to figure out how to use this URL into a development environment like PyCharm to be able to read the frames from this URL into a python script, for example.
url="http://127.0.0.1:8000/video_feed/?start_frame=4000&end_frame=5001"
while True:
resp = urllib.request.urlopen(url)
response = resp.read()
data = resp.split(b'\r\n\r\n', 1)[1]
i = np.frombuffer(data, dtype=np.uint8)
img = cv2.imdecode(i, cv2.IMREAD_UNCHANGED)
cv2.imshow("frame", img)
if cv2.waitKey(16) & 0xFF==ord('q'):
break
cv2.destroyAllWindows()
So this is what I have tried for reading the frames into PyCharm but it only reads the first frame. I want it to be able to ingest all of the frames from the URL. I know that there is something I am not understanding when it comes to URL's or generator functions, so any refactoring or help is greatly appreciated!

On the Flask server side the adjustment is made to the generator function:
yield (b'--frame\r\n'
b'Content-Type: image/jpeg\r\n\r\n' + stringData + b'\r\n')
And then read into an IDE like pycharm as such:
import cv2
vcap = cv2.VideoCapture('http://127.0.0.1:8000/video_feed/?
start_frame=4000&end_frame=5001')
while True:
ret, frame = vcap.read()
if frame is not None:
cv2.imshow('frame', frame)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
else:
print("Frame is None")
break
vcap.release()
cv2.destroyAllWindows()
print("Video stop")

How to Convert Open-CV frames to m3u8 streams?

I am reading an rtsp(local rtsp link) stream from my cctv camera connected on LAN.
My Main Goal :-
I want to perform some processing on the frames and want to display via m3u8 in real time or nearly real time so that i can display in the frontend using hls.js.
Currently i am trying to create video in realtime so that using ffmpeg i can create the m3u8 .
Sharing my code below.
import cv2
from moviepy.editor import *
import numpy as np
import time
url = "rtsp://username:password#192.168.1.100:10554/Streaming/channels/401"
cap = cv2.VideoCapture(url)
def make_video_file(clips):
try:
print(f"clips = {clips}")
video_clip = concatenate_videoclips(clips,method='compose')
video_clip.write_videofile("video-output.mp4",fps=30)
except Exception as e:
print(e)
FRAME_COUNTER = 0
NUMBER_OF_FRAMES = 30
CLIPS = [0 for i in range(NUMBER_OF_FRAMES)]
while True:
ret, frame = cap.read()
# print(frame)
if not ret:
continue
CLIPS.pop(0)
CLIPS.append(ImageClip(frame).set_duration(1))
if FRAME_COUNTER == NUMBER_OF_FRAMES:
try:
FRAME_COUNTER = 0
make_video_file(CLIPS)
except:
pass
cv2.imshow('frame', frame)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
NUMBER_OF_FRAMES += 1
cap.release()
cv2.destroyAllWindows()

OpenCV Python IP Camera live image

at the moment I am reading an ip cameras live image by using the following code:
def livestream(self):
print("start")
stream = urlopen('http://192.168.4.1:81/stream')
bytes = b''
while True:
try:
bytes += stream.read(1024)
a = bytes.find(b'\xff\xd8')
b = bytes.find(b'\xff\xd9')
if a != -1 and b != -1:
jpg = bytes[a:b+2]
bytes = bytes[b+2:]
getliveimage = cv2.imdecode(np.frombuffer(jpg, dtype=np.uint8), cv2.IMREAD_COLOR)
livestreamrotated1 = cv2.rotate(getliveimage, cv2.ROTATE_90_CLOCKWISE) #here I am rotating the image
print(type(livestreamrotated1)) #type at this point is <class 'numpy.ndarray'>
cv2.imshow('video',livestreamrotated1)
if cv2.waitKey(1) ==27: # if user hit esc
exit(0) # exit program
except Exception as e:
print(e)
print("failed at this point")
Now I want to integrate the result-image into Kivy-GUI and want to get rid of the while-loop since it freezes my GUI. Unfortunately the loop is necessary to recreate the image byte-by-byte. I would like to use cv2.VideoCapture instead and schedule this multiple times per second. This is not working at all, I am not able to capture the image from the live stream this way...where am I wrong?
cap = cv2.VideoCapture('http://192.168.4.1:81/stream?dummy.jpg')
ret, frame = cap.read()
cv2.imshow('stream',frame)
I read in some other post that a file-ending like "dummy.jpg" would be necessary at this point, but it is still not working, the program freezes.
Please help. Thank you in advance!

If you want to decouple your reading loop from your GUI loop you can use multithreading to separate the code. You can have a thread running your livestream function and dumping the image out to a global image variable where your GUI loop can pick it up and do whatever to it.
I can't really test out the livestream part of the code, but something like this should work. The read function is an example of how to write a generic looping function that will work with this code.
import cv2
import time
import threading
import numpy as np
# generic threading class
class Reader(threading.Thread):
def __init__(self, func, *args):
threading.Thread.__init__(self, target = func, args = args);
self.start();
# globals for managing shared data
g_stop_threads = False;
g_lock = threading.Lock();
g_frame = None;
# reads frames from vidcap and stores them in g_frame
def read():
# grab globals
global g_stop_threads;
global g_lock;
global g_frame;
# open vidcap
cap = cv2.VideoCapture(0);
# loop
while not g_stop_threads:
# get a frame from camera
ret, frame = cap.read();
# replace the global frame
if ret:
with g_lock:
# copy so that we can quickly drop the lock
g_frame = np.copy(frame);
# sleep so that someone else can use the lock
time.sleep(0.03); # in seconds
# your livestream func
def livestream():
# grab globals
global g_stop_threads;
global g_lock;
global g_frame;
# open stream
stream = urlopen('http://192.168.4.1:81/stream')
bytes = b''
# process stream into opencv image
while not g_stop_threads:
try:
bytes += stream.read(1024)
a = bytes.find(b'\xff\xd8')
b = bytes.find(b'\xff\xd9')
if a != -1 and b != -1:
jpg = bytes[a:b+2]
bytes = bytes[b+2:]
getliveimage = cv2.imdecode(np.frombuffer(jpg, dtype=np.uint8), cv2.IMREAD_COLOR)
livestreamrotated1 = cv2.rotate(getliveimage, cv2.ROTATE_90_CLOCKWISE) #here I am rotating the image
# acquire lock and replace image
with g_lock:
g_frame = livestreamrotated1;
# sleep to allow other threads to get the lock
time.sleep(0.03); # in seconds
except Exception as e:
print(e)
print("failed at this point")
def main():
# grab globals
global g_stop_threads;
global g_lock;
global g_frame;
# start a thread
# reader = Reader(read);
reader = Reader(livestream);
# show frames from g_frame
my_frame = None;
while True:
# grab lock
with g_lock:
# show
if not g_frame is None:
# copy # we copy here to dump the lock as fast as possible
my_frame = np.copy(g_frame);
# now we can do all the slow manipulation / gui stuff here without the lock
if my_frame is not None:
cv2.imshow("Frame", my_frame);
# break out if 'q' is pressed
if cv2.waitKey(1) == ord('q'):
break;
# stop the threads
g_stop_threads = True;
if __name__ == "__main__":
main();

Cant open video with videoCapture opencv

I have following code which reads frames from video file and stores as jpg. The code works fine if I read frames from camera directly but for video file it doesn't read the frames.
cap = cv2.VideoCapture('C:/Users/lostpanda.mp4')
#cap = cv2.VideoCapture(0)
count = 0
while cap.isOpened():
ret,frame = cap.read()
print(ret,frame)
cv2.imshow('window-name', frame)
name = 'C:/Users/video_testing/video-frames/' + str(count) + '.jpg'
#cv2.imwrite("frame%d.jpg" % count, frame)
cv2.imwrite(name,frame)
count = count + 1
if cv2.waitKey(10) & 0xFF == ord('q'):
break
Thanks

You can try this instead:
import cv2
import os
# Read the video from specified path
cam =cv2.VideoCapture(r"C:/Users/lostpanda.mp4")
try:
# creating a folder named data
if not os.path.exists('video-frames'):
os.makedirs('video-frames')
# if not created then raise error
except OSError:
print ('Error: Creating directory of data')
# frame
currentframe = 0
while(True):
# reading from frame
ret,frame = cam.read()
if ret:
# if video remains continue creating images
name = './video-frames/frame' + str(currentframe)+ '.jpg'
print ('Creating...' + name)
# write extracted images
cv2.imwrite(name, frame)
#Counter to show number of frames that are being created
currentframe += 1
else:
break
# Release all space and windows once done
cam.release()
cv2.destroyAllWindows()

Save multiple images with OpenCV and Python

I'm using OpenCV and Python to take images. However currently I can only take one picture at a time. I would like to have OpenCV to take multiple pictures. This is my current code.
import cv2.cv as cv
import time
cv.NamedWindow("camera", 1)
capture = cv.CaptureFromCAM(0)
while True:
img = cv.QueryFrame(capture)
cv.ShowImage("camera", img)
cv.SaveImage('pic.jpg', img)
if cv.WaitKey(10) == 27:
break

Your code overwrite a file. Save to different file each time.
For example:
import cv2.cv as cv
import time
cv.NamedWindow("camera", 1)
capture = cv.CaptureFromCAM(0)
i = 0
while True:
img = cv.QueryFrame(capture)
cv.ShowImage("camera", img)
cv.SaveImage('pic{:>05}.jpg'.format(i), img)
if cv.WaitKey(10) == 27:
break
i += 1

A minimal example of what you'd like to do, based on the c++ binded interface.
import cv2
cpt = 0
maxFrames = 5 # if you want 5 frames only.
try:
vidStream = cv2.VideoCapture(0) # index of your camera
except:
print "problem opening input stream"
sys.exit(1)
while cpt < maxFrames:
ret, frame = vidStream.read() # read frame and return code.
if not ret: # if return code is bad, abort.
sys.exit(0)
cv2.imshow("test window", frame) # show image in window
cv2.imwrite("image%04i.jpg" %cpt, frame)
cpt += 1
A full example of script, able to read from a camera index, or a file. Includes some failsafes and some information about read device.
usage: record.py [source] [target folder]
#!/usr/bin/env python
import cv2
import sys
import os
cpt = 0
maxFrames = 30
try:
targetDir = sys.argv[2]
except:
targetDir = "" # if no argument, then use current directory
try: # read input. eval if to transform video index to int
vidStream = cv2.VideoCapture(eval(sys.argv[1]))
except:
print "problem opening input stream"
sys.exit(1)
if not vidStream.isOpened():
print "capture stream not open"
sys.exit(1)
# informations in case the input is a video file.
nFrames = vidStream.get(cv2.cv.CV_CAP_PROP_FRAME_COUNT)
print "frame number: %s" %nFrames
fps = vidStream.get(cv2.cv.CV_CAP_PROP_FPS)
print "FPS value: %s" %fps
# note that we could use frame number here, or "while 1"
# so we could read from a live written file or capture devide.
while cpt < maxFrames:
ret, frame = vidStream.read() # read frame and return code.
if not ret:
print "end of stream"
sys.exit(0)
cv2.imshow("test window", frame) # show image in window
cv2.imwrite(os.path.join(targetDir, "image_%04i.jpg" %cpt), frame)
cpt += 1
keyPressed = cv2.waitKey(1) # time to wait between frames
if keyPressed != -1: # if user pressed a key, stop recording.
sys.exit(0)

change the name of the image to be saved to " [image name] [a number which increase after every loop] "
By doing this your image will be stored with a new name after every loop.. otherwise all the images will overwrite the same name !
import cv2.cv as cv
import time
cv.NamedWindow("camera", 1)
capture = cv.CaptureFromCAM(0)
num = 0
while True:
img = cv.QueryFrame(capture)
cv.ShowImage("camera", img)
cv.SaveImage('pic'+str(num)+'.jpg', img)
if cv.WaitKey(10) == 27:
break
num += 1
now your images will be saved as pic0.jpg, pic1.jpg, pic2.jpg and so on..

i think this wil helpful...
import cv2
vid = cv2.VideoCapture("video.mp4")
d = 0
ret, frame = vid.read()
while ret:
ret, frame = vid.read()
filename = "images/file_%d.jpg"%d
cv2.imwrite(filename, frame)
d+=1
this will save every frame with different name.