Opencv videocapture slow. putText () and lastly displayed them with cv.
Opencv videocapture slow Here my test result: **Integrated USB Camera (HP 5MP Camera)** PERFORMANCE TEST CAMERA 0 Connected! Time taken: 9. Does anyone know how to speed up this process? The rest of my code finishes instantly after the picture is finally taken with the external webcam. read () Asked 6 years, 7 months ago Modified 3 years, 8 months ago Viewed 11k times Jan 8, 2013 · Class for video capturing from video files, image sequences or cameras. putText () and lastly displayed them with cv. 2) and python to implement it. If I run the video capture stream with no pixel manipulation applied, the stream works fine and has a smooth frame rate. Any Oct 12, 2021 · Hello everyone. You could use a simple spin-lock to synchronize reading frames between the real worker thread and the third thread. Indeed, when I display a simple Rtsp video stream via OpenCv, I have no problems. set (cv2. read () is that you are using the YUYV format, which is uncompressed and requires more bandwidth and processing power than the MJPG format, which is compressed and can handle higher resolutions faster. grab() to avoid overhead. At a resolution at which it can output 120FPS, I’m only getting 20-40FPS using a very simple OpenCV application, while ffmpeg fed directly from the webcam gets ~60FPS while also doing h264 encoding and streaming, so something is definitely off. 2 4. I am trying to do this through OpenCV with Python, but I am running into some issues. Feb 23, 2021 · Topic Replies Views Activity Rtsp issue while streaming using opencv Python 0 940 April 27, 2021 Lot of Delay with my RTSP cam with OpenCV on Python Python 32 33135 February 8, 2024 Cannot read RTSP Stream with less than 1 FPS Python videoio 14 4510 July 12, 2022 Can't get RTSP stream with openCV 4. When running on my computer, there is a delay of more than 10 seconds and fps drops. I will run this project on a server. 5. This thread should use the cv::VideoCapture. 10 Detailed description VideoCapture::grab () is slow in cpp. I have a question regarding the OpenCV VideoCapture class. VideoCapture (0). release() cv. If I use VideoCapture capture = new VideoCapture (0, VideoCaptureAPIs. 92867 seconds Read Nov 5, 2012 · I am building an OpenCV application which captures a video from camera and overlays it on another video after removing the background. However, a common challenge arises: lag in real-time video capture. 0 3. Nov 5, 2021 · Summary of your issue VideoCapture. 1 to measure the FPS of my camera and I found the actual FPS measured is way below my expectation. I tried to use VideoCapture and get video from several streams, but my computer can’t read frames from stream faser than stream put them into buffer. The stream is very slow at the same exposure level. that’s why you’re supposed to do it once, and then read multiple frames. Aug 22, 2022 · what do you mean, “slow”? you are reading a single frame. VideoCapture ('video. It was very slow (2 frames/sec) and the latency was seconds. 0 Python OpenCV version: 4. Questions: How to increase Sep 22, 2016 · I have no idea why it's so slow on OpenCV. VideoCapture (2) cap. CAP_PROP_FRAME_WIDTH, 640) cap. Jul 23, 2019 · Hi! I have gotten a Logitech BRIO Webcam, which delivers nice smooth 30 fps of 4k images in the native Windows Camera App. I am not able to achieve a reasonable speed as it is playing Feb 6, 2023 · I first wrote code that grabbed frames with cv. I use the script below to check the speed I can capture frames with OpenCV on Python, but unfortunately I can't capture at the same speed, not even close. hpp" #include <time. OpenCV provides a very simple interface to do this. However, I applied a threshold loop as a test, and my stream undergoes major lag and updates once every few seconds. read() if not ret: break cv. Fast a Video FPS using cv2. VideoCapture is a class in the OpenCV library that allows us to capture video from different sources, and perform various tasks on the video such as reading, processing, and writing on video files. I am looking for some avenues to explore because I can't find solutions despite my research on the Net. Why was this placed on the moderation queue? Oct 28, 2022 · The main reason for the slow performance of vid. x64: 5 to 10 seconds x86: 1 to 2 seconds I noticed this issue was raised but there wasn't a solution. How to increase performance of OpenCV cv2. It makes delay of image. set takes a lot of time compared to the other operations like connecting to a camera. V4L2) cap… Jul 23, 2025 · The cv2. 3 in my Java app. 7. Suppose that we have the following code import cv2 import time cap = cv2. VideoWriter () Capture Video from Camera Often, we have to capture live stream with a camera. VideoCapture function of the OpenCV library. To solve this, I took the last frame and made it skip the following frames. Now the image is skipping. set(cv2 Feb 28, 2023 · Hi, trying to start simple code to show in the window video from webcam, but window with video appear only after 5 minutes, what is wrong? import cv2 # Open camera cap = cv2. of course, initializing the camera device takes a bit of time. Jun 7, 2022 · I ran the following python code and the resulting video stream was buttery smooth and fast: import cv2 as cv cap = cv. Sep 3, 2021 · I have tried two software to capture video stream from this camera using c++, libUVC and OpenCV. with VideoCapture. However it takes 20-30 seconds for the camera to open initially. You will learn these functions : cv. Let's capture a video from the camera (I am using the built-in webcam on my laptop Sep 12, 2024 · Hi everybody, setting camera properties like height, width, frameRate etc. imshow('frame', frame) if cv. 29. According to my tests, this is happening only for USB cameras. I have asked some guys, they told me that some old frames will store in the buffer and i should use a worker thread to get the latest frame. While the next frame is being read, decode, and returned the OpenCV application is completely blocked. waitKey(1) == ord('q'): break cap. VideoCapture (), cv. May 16, 2017 · Hello I have a camera that captures video (according to the specifications) at a resolution of 640x480 at 120fps. Aug 22, 2022 · I tried, but it does not work. If I use CAP_MSMF (or CAP_ANY), it takes several minutes for the camera to open up, delaying my application start time. I've determined that the part that is slowing everything down is the capture process; frames aren't getting from the camera to the cpu fast enough. Feb 6, 2017 · Have you ever worked with a video file via OpenCV’s cv2. imshow (). VideoCapture. the cv2. OpenCV real time streaming video capture is slow. CAP_PROP_FRAME Dec 28, 2020 · Hello, I was using OpenCV 4. But when i debug,i find that the frame i got is the old frame. VideoCapture(0) vid. h> using namespace cv; using namespace std; int main(int argc, char** argv) { // Start Dec 6, 2023 · System Information CPP OpenCV version: 4. Any answer will be helpful. I also notice it causes delay in Jan 6, 2017 · I am trying to read a high resolution video using OpenCV VideoCapture and it seems to be extremely slow. I am working on a vision project using OpenCVSharp, my webcam I am testing with is a C925e If I open my camera with VideoCapture capture = new VideoCapture (0); then I can get my 30fps @ 1080p or 60fps @ 720p as expected. The code I used for measurement is from How to find frame rate or frames per second (fps) in OpenCV ( Python / C++ ) ? | Learn OpenCV #include "opencv2/opencv. 2 C++ Aug 25, 2020 · The reason VideoCapture is so slow because the VideoCapture pipeline spends the most time on the reading and decoding the next frame. Learn to capture video from a camera and display it. Here is how the class can be used: Dec 3, 2020 · I am trying to write a script to manipulate video from a webcam. import cv2 from time import time cap = cv2. IP cameras are fine. Jun 29, 2020 · I am trying to open my Logitech HD Pro C910 USB webcam using OpenCV 4. VideoCapture To increase the video FPS in Python, we will use cv2. 04 8 cores i7 3. In my code,i have use VideoCapture to do that. DSHOW); as I have seen recommended OpenCv webcam reading official code is very slow Asked 8 years ago Modified 5 years, 1 month ago Viewed 11k times Jan 24, 2022 · Hi all - I’m getting started with OpenCV. Why is it if i read a video file using cv2. To switch to the MJPG format, you need to add one more line to your code after initializing the vid object: vid = cv2. I’m not sure if I need to set some different properties, but I’ve tinkered a bit and doesn’t seem to matter. 2 My tries: Make buffer short I May 4, 2015 · Hackaround 2 A different solution, inspired by this post, is to create a third thread that grabs frames continuously at high speed to keep the buffer empty. I found that libUVC will deliver call back with YUYV image at 30 fps. En 2 days ago · Goal Learn to read video, display video, and save video. The class provides C++ API for capturing video from cameras or for reading video files and image sequences. 00GHz Memory 32GB). I need a faster way to pass the reading frame into image processing on my Computer (Ubuntu 18. 214. please clarify. I wold like some tips to make the capture faster. avi') the fps is very very very low? I want the fps to be the same as when i play the video using a video player (30fps). Similar question Here, i have two questions, If the buffer can Dec 10, 2020 · 14 4512 July 12, 2022 RTSP is slow when using Opencv Python rtsp , highgui , videoio 5 8991 February 24, 2021 Face recognition ip camera latency 6-10 ms Python videoio , objdetect 4 1894 March 1, 2021 Face Recognition is very slow with rtsp camra in opencv python programming 1 451 April 12, 2023 Can't get RTSP stream with openCV 4. However I am using an haarcascaded face detection code and I have a lot of latencies and frames loss when i use it in my code. 0 in Python, this seems impossible. Because of this buffer accumulates more and more frames. Your entire video processing pipeline crawls along, unable to process more than one or two frames per second — even though you aren’t doing any type of computationally expensive image processing Jul 11, 2021 · System information (version) Opencv 4. I read somewhere changing the buffer sizes might help, but I tried setting all kinds of buffer Jan 20, 2017 · Things I have tried: -Adding a sleep function after loading a new frame to help do less computation per second (to improve the lag) -Using two different names for the video capture when launching the camera (cap and cap2) -Using the exact same code twice in a row -Simplifying the program to be just the task of opening, closing, and reopening I Feb 2, 2022 · I am trying to make a simple Video player with OpenCV as a beginner project. 2 C++ videoio 11 8414 September 16, 2021 Face Recognition is very slow with rtsp camra in Sep 29, 2024 · When I try to use the webcam video device directly in OpenCV, the recorded footage although smooth, is sped up. Everything is fluid. ip='rtsp://admin:@10. edit: It May have something to do with VideoCapture buffer. my processing module take about 40ms per run. I tried on both, an I5 processor and an I9 processor, but the Python script runs very slowly. 18 aarch64 Compiler: aarch64-linux-gnu-gcc 9. How to solve this problem? python 3. Methods read() or grab() takes from buffer the first frame, not last. I'd like it to run at 60fps, but I can't seem to get it to that speed. 1. No face recognition feature. which is too slow. How to drop frames or get synced with real time? I'd like to set up an opencv system to process either HLS streams or RMTP streams, however, I am running into a strange issue regarding a reduced frame-rate and an accumulating lag. 0 Python version: 3. destroyAllWindows() However, after running the code given here (and changing deviceID to 2), and building with the following Oct 26, 2015 · I use a camera to get frames continuesly. resize (), drew geometry on the frames, annotated them with cv. 1 Operating System: Linux kylin 5. 3. Is there a way to make it aways use the latest image? edit2: I could get good lag results on VLC, after reducing cache/buffer to 300ms, I believe network and processing are not to blame. 6 days ago · OpenCV, a popular open-source computer vision library, is widely used for capturing and processing video streams. VideoCapture(2) while True: ret, frame = cap. I’m on Win11, Python3. 120 Aug 22, 2022 · what do you mean, “slow”? you are reading a single frame. Also there is a similar question here. Using OpenCV 4. 2, opencv 4. 2 platform Linux/Windows USB/UVC camera Linux: It took about 3 seconds to load usb camera Jan 14, 2020 · I use opencv (4. One other odd thing is that on one start it could stay locked at 50FPS, while Apr 14, 2021 · Hello. Here is how the class can be used: Jan 8, 2013 · Class for video capturing from video files, image sequences or cameras. VideoCapture (0) # Changing size of slide ca… Jun 2, 2023 · I’m doing face recognition with python opencv. Open() is significantly slower on x64 as compared to x86. 4. 2. . Jul 12, 2019 · When I set it to VideoCapture (0), it works much faster but I need to use my external webcam instead so I have to set it to VideoCapture (1). VideoCapture ('/dev/video0', cv2. VideoCapture (), did the analysis with numpy and scipy, made a reduced-size frame for display with cv. read() read frame (frame size : 720x1280) will take about 120~140ms. VideoCapture function and found that reading frames just felt slow and sluggish? I’ve been there — and I know exactly how it feels. I'm working on an application in python using opencv for use in athletic coaching. What changes should i make to achieve this? Dec 27, 2021 · Hi, As per the title, I’m seeing very slow frame reads from webcam. 8. How can I make it more fluent? The camera I use is Hikvision. Feb 12, 2025 · Fixing OpenCV issues: optimizing image processing, reducing memory usage, improving video capture performance, and leveraging parallel processing. When I run using my laptop’s built-in webcam, OpenCV gets going pretty quickly (averages under 300ms), when I switch to my USB-connected webcam, it takes about 18 seconds. nqc4lj6teefrh8tcu49t80b6xp7mq8lbx98vz