Video IO using HighGUI

An essential component of computer vision is video input/output (IO), which enables processing of video data in tasks like object detection, face recognition, and motion detection. The OpenCV package contains a module called HighGUI that makes it easier to conduct video IO using HighUI operations. In this piece, we'll give a general overview of video IO using HighGUI in computer vision, go over its benefits and features, and show you how to read, write, and display video files using it.

What is Video I/O?

• Video I/O refers to the process of inputting and outputting video data in computer systems. It involves reading video data from a source, such as a file or a camera, and writing video data to a destination, such as a file or a display.
• Video I/O is an essential component in many computer vision, image processing, and multimedia applications. It allows you to work with video content, manipulate frames, extract information, apply algorithms, and perform various operations on video data.
• Input operations in video I/O involve reading video frames from a source. The source can be a video file in a specific format, a live video stream from a camera, or even a network stream. The frames are typically represented as a sequence of images or matrices, where each frame represents a single image at a particular time.
• Output operations in video I/O involve displaying or storing video frames. Displaying video frames allows you to visualize the video content in real-time, either on a computer screen or any other display device. Storing video frames allows you to save the video content as a file in a specific video format for later use or distribution.
• Video I/O also provides functionality for handling video codecs, which are algorithms or libraries used to encode and decode video data. Codecs are responsible for compressing video data for efficient storage and transmission, as well as decompressing it for playback or further processing.

What is HighGUI?

HighGUI is a module provided by the OpenCV library, which stands for High-Level Graphical User Interface and is designed to provide a simple and convenient interface for basic graphical user interface (GUI) operations, particularly for image and video I/O.

HighGUI provides a straightforward and easy-to-use interface for these GUI-related tasks, making it convenient for quick prototyping and development of computer vision and image processing applications. However, it's worth noting that HighGUI's capabilities are relatively basic compared to more advanced GUI libraries, and it's primarily focused on image and video I/O operations. For complex graphical interfaces, you may need to use additional libraries or frameworks tailored for GUI development.

Importance of HighGUI in Video IO

HighGUI's value in video IO stems from its capacity to make the procedure simpler. A robust tool for loading, viewing, and writing video files is provided by HighGUI, which has a simple GUI that abstracts away technical complexity. Rather than investing time and energy in video IO using HighUI operations, this enables developers to concentrate on the core functionality of their computer vision applications. HighGUI is a flexible tool for processing video data from numerous sources because it can handle a wide range of video formats.

• For carrying out video IO using HighUI activities, HighGUI offers a variety of features, such as reading and writing video files, displaying video frames in a GUI, and taking user input.
• Highly functional computer vision applications can be made by developers by combining the HighGUI functionalities with OpenCV's image processing and computer vision tools.
• HighGUI is a flexible tool for processing video data since it can handle a variety of video formats. HighGUI can handle many formats with ease, offering compatibility and flexibility in video IO using HighUI operations whether the video is imported from previously recorded files or captured from a camera.
• Enables rapid prototyping and iteration: Rapid development and iteration are possible because of HighGUI, which makes it simple to import and display video data for computer vision algorithms. Iterative development is made easier by the intuitive GUI since developers can immediately evaluate the results of their algorithms and make the required modifications.
• Increases developer productivity by giving developers a more efficient interface for video IO. Developing video IO using HighUI functions more quickly, frees up developers' time to work on more complex projects.  

Features and Advantages of HighGUI

• User-friendly GUI: HighGUI offers a GUI that makes the video IO using the HighUI process simpler. Developers may now load, show, and write video files without having to worry about the nitty-gritty.
• Wide video format support: A broad variety of video formats, including AVI, MPEG, MP4, and more, are supported by HighGUI. As a result, it can be used as a flexible tool to process video data from a variety of sources.
• Real-time video capture: It is made possible by HighGUI, which is helpful for applications that call for live video broadcasting or monitoring.
• Video compression: HighGUI offers settings for video compression, which can assist reduce the size of video files and enhance performance in applications that handle video.

How HighGUI Work with OpenCV?

HighGUI is an OpenCV graphical user interface (GUI) module that offers capabilities for input/output operations, user interaction, and the display of images and videos. It serves as a conduit between the user and the underlying computer vision algorithms, facilitating the visualisation and interaction of image and video data.

What HighGUI does with OpenCV is as follows:

• Displaying Images and vidoes: HighGUI has methods for displaying images and movies in Windows, such as cv2.imshow(). The user can move, resize, and close these windows. Additional capabilities provided by HighGUI include window resizing, window naming, and window flags for modifying how displayed pictures and movies behave.
• Handling User Input: HighGUI enables you to record user input events including keyboard pushes, mouse clicks, and trackbar movements. With HighGUI, callback functions may be registered to handle these events and take particular actions in response to user input.
• Creating Graphical User Interfaces (GUIs) creation of graphical user interfaces (GUIs) is made possible by HighGUI, which offers tools for designing unique GUIs for computer vision applications. It provides resources for creating interactive applications, such as trackbars (cv2.createTrackbar()) that let users change settings interactively, buttons (cv2.createButton()) that launch actions, and other UI components.
• Video Input/Output: Thanks to HighGUI's support for these activities, you can read video frames from files or record them from cameras. It offers tools like cv2.VideoWriter() to save video frames to a file and cv2.VideoCapture() to connect to cameras or open video files.

Reading and Writing Video Files using HighGUI

HighGUI is a graphical user interface library in OpenCV that provides a simple way to read, write, and display image and video data. In this article, we will focus on reading and writing video files using HighGUI.

a. Introduction to Reading and Writing Video Files

A crucial task in many computer vision applications, including object detection and video surveillance, is reading and writing video files. By giving programmers access to a variety of functions that let them load and save video files in different formats, HighGUI makes this process easier.

b. Reading Video Files with HighGUI

Use the cv2.VideoCapture() function to load the video and the read() method to loop over the frames to retrieve frames and write each frame to a separate image file using imwrite().

1. Loading a Video File

2. Extracting Frames from a Video File

Output

c. Writing Video Files with HighGUI

You must first build a VideoWriter object to produce a new video file. The output filename, codec to utilise for compression, frames per second (FPS), and frame size are just a few of the options that this object accepts.

1. Creating a Video File

2. Writing Frames to a Video File Once the VideoWriter object has been created, you can use the write method to add frames to the file. The frame to write to the file is the only parameter this function accepts.

Output: The output will be stored as a video file in the name of output.mp4

d. Errors in Reading and Writing Videos

• File not found error: When the video file path is incorrect or the file does not exist, a file not found error will appear. You must confirm that the file exists at the specified location and that the file path is accurate to resolve this problem.
• Unsupported codec error: This error appears when OpenCV cannot play the video codec that was used to create the video file. Installing the necessary codec or converting the video file to a different format could be necessary to resolve this problem.
• Corrupted file error: When a video file is corrupted, it cannot be read or written and results in an error. Use a different video file or try to repair the file to resolve this issue.
• Permission error: This error occurs when you do not have permission to read or write to the video file. To fix this error, you need to ensure that you have the required permission to access the file.

Displaying Video using HighGUI

we will explore how to display video using HighGUI in OpenCV. HighGUI provides an easy-to-use graphical user interface for displaying video, which is crucial for analyzing and understanding computer vision algorithms.

By creating dynamic and user-friendly computer vision applications, we can analyze and evaluate video data in real time. In the following section, we will introduce the concept of displaying video and explore how HighGUI can help us achieve it.

Introduction to Displaying Video

Applications for computer vision must include visual display. It enables us to see and comprehend the results of algorithms used on video data. An accessible graphical user interface for presenting video is offered by HighGUI in OpenCV.

We can show video in a window using HighGUI, design unique graphical user interfaces (GUIs), and use a mouse and keyboard to interact with video data. We can create dynamic, user-friendly computer vision applications that analyze and evaluate a video in real-time thanks to HighGUI.

For activities like object tracking, motion detection, and video analysis, this feature is very helpful. We can view the output of our computer vision algorithms and make defensible judgements based on the given data by showing video frames via a graphical user interface (GUI).

Creating a Graphical User Interface (GUI) using HighGUI

The cv2.namedWindow() function is used to create a window with the name 'Video Player'. The cv2.WINDOW_NORMAL flag allows the window to be resized by the user. This provides flexibility in adjusting the window size according to the video's resolution or the user's preference.

Displaying Video in the GUI and Handling User Input in the GUI

If a frame is successfully read (ret is True), the frame is displayed in the named window using the cv2.imshow() function. The first argument Video Player is the name of the window, and the second argument frame is the actual frame to be displayed. And cv2.waitKey(1) is used for handling user input, in this case to stop the application.

Output:

Examples of HighGUI in Computer Vision Applications

Now that we have an understanding of HighGUI and how it can be used to display video, let's take a look at some examples of how HighGUI is utilized in computer vision applications. One such example is object detection, which involves locating and identifying objects of interest in an image or video stream.

HighGUI provides a robust and adaptable foundation for creating object detection applications, making it a valuable tool in a variety of fields such as robotics, autonomous cars, and surveillance systems. In the following section, we will explore how HighGUI can be utilized for object detection in more detail.

Object Detection

A key job in computer vision called object detection involves finding and locating things of interest in an image or video stream. A robust and adaptable foundation for creating object detection apps is provided by HighGUI in OpenCV.Applications for object detection utilizing HighGUI include robotics, autonomous cars, and surveillance systems. Using object detection, for instance, a surveillance system can spot suspicious activity and notify security personnel. Object detection is a tool that autonomous vehicles can employ to identify impediments and prevent crashes. Robotic applications that use object detection can find and identify important things.

Face Recognition

Face detection techniques can be used with HighGUI to recognize and track faces in real-time camera video inputs. Face recognition algorithms can be used to match the looks with recognized faces in a database after they have been found and tracked, revealing information about the individual's identity in the frame. Applications like surveillance, access control, and attendance management can benefit from using HighGUI to display the video feed and the outcomes of the face detection and identification algorithms. It permits instant identification of humans in the frames and offers real-time visual feedback of the system's performance.

Optical Flow

Optical flow is a technique used in computer vision to track the motion of objects in a video stream. It involves computing the displacement of pixels between consecutive frames in a video sequence. HighGUI can be used to display the results of optical flow algorithms in real-time, making it easier to visualize and analyze motion patterns. The first step in employing optical flow in HighGUI is to capture a video stream with OpenCV's VideoCapture class. Then, one of some algorithms, including the Lucas-Kanade method or the Farneback method, can be used to calculate optical flow. The optical flow vectors are commonly computed by these techniques over the course of two consecutive frames.

Motion Detection

Motion detection is a common task in computer vision and is widely used for security or surveillance applications. It involves identifying changes in the video frames and detecting any moving objects in the scene. HighGUI can be used to display video frames in real-time and highlight any motion detected in the frames. One of the simplest ways to perform motion detection is by using the difference between two consecutive frames. This approach involves subtracting the pixel values of two frames and thresholding the resulting difference image to identify the moving objects.