ffmpeg - v4l2 image format conversion

Goal: The camera data is collected through v4l2, and then the image format is converted and stretched and zoomed . Code: #include <stdio.h> #include "libavcodec/avcodec.h" #include "libavformat/avformat.h" #include "libavdevice/avdevice.h" #include "libswscale/swscale.h" #define d

Understanding and use of @property in python

When looking at the code of the great god on git, there is such a paragraph: Then I was very curious about what it was. Then I went to Baidu and checked a lot of information, but I didn't understand it clearly. Finally, I slowly realized that this is equivalent to a restricted use. The example I found on the Internet is probably: class Student(object):

AttributeError: module ‘asyncio‘ has no attribute ‘run‘

Problem Description import asyncio async def count(): print("One") await asyncio.sleep(1) print("Two") async def main(): await asyncio.gather(count(), count(), count()) asyncio.run(main()) 1234567891011 report an errorAttributeError: module 'asyncio' has no attribute

ModuleNotFoundError: No module named 'cv2' (install cv2)

1. Problem: ModuleNotFoundError: No module named 'cv2' (  there is an error in  import cv2  in Pycharm ) 2. Solution: install cv2 pip install opencv-python (if only the main module is used, use this command to install)pip install opencv-contrib-python (if you need to use the main module and contrib module, use this command to install)The requirements.tx

webrtc small note-aiortc-mediasoup push stream pull stream

When I pushed the stream to mediasoup with aiortc, I found that there was no video. I thought it was a problem with bandwidth or codec. Finally, I found that the key frame request was not sent. elif isinstance(packet, RtcpPsfbPacket) and packet.fmt == RTCP_PSFB_PLI: self._send_keyframe() RTCP_PSFB_PLI = 1 ； But the key frame request of mediasoup's rtcp

Linux view process occupied network speed and traffic usage

There are three commands vnstat, iftop, nethogs (recommended) All need to install additional software using yum or apt-get   1. Use vnstat to view the interface statistics report vnstat -i eth0 -l #Real-time traffic situation There are other commands to view using --help After ctrl+c ends, the traffic statistics results during the monitoring period

Install opencv under Python3.6

opencv installation problem 1. First of all, you need to have a python installed Python environment, Anaconda is recommended , because my 3.6 python version, opencv installed in the Anaconda environment. ===================================================== ================ 2. Anaconda co

pip install aiohttp error: Could not find a version that

Use pip install aiohttp to report an error as shown below: Cause of the problem: The package is abroad, the network connection is slow, if the connection is unsuccessful for a long time or the download is unsuccessful, an error will be reported. Solution: Increase the connection wait time Solution statement: pip --default-timeout=100 install aiohttp

After Coturn is installed, when turnadmin adds a user, the solution prompts Error Retrieving SQLite

1. After installing coturn with reference to the documentation, use turnadmin -a -u your_name -p your_password -r your_realm to report an error, Error Retrieving SQLite , prompting that the database cannot be opened, the file is encrypted or does not exist. After thinking about it for a day, refer to the command on the official website and modify it The com

Running c# console application on Centos7

Official website: https://docs.microsoft.com/en-us/dotnet/core/install/linux-centos Before installing .NET, run the following commands to add the Microsoft package signing key to the list of trusted keys and add the Microsoft package repository. Open a terminal and run the following command

Android opens SDK-monitor.bat and reports an error Windows cannot find the file "lib\monitor-location"

1. Open the monitor.bat system in the SDK-tools directory to report an error 1. Open the file 2. Error Second, the solution: Run \SDK\tools\lib\monitor-x86_64\monitor.exe

Coturn installs and deploys configuration test in centos7

content coturn installation coturn configuration coturn test 1.coturn installation Operating environment: centos7 Install openssl and openssl-devel yum install opensslyum -y install openssl-devel   Download and install libevent wget https://github.com/downloads/libevent/libevent/libevent-2.0.21-stable.tar.gztar zxvf libevent-2.0.21-stable.tar.g

SSL/TLS Mutual Authentication (1) -- How SSL/TLS Works

Some references to this article: https://www.wosign.com/faq/faq2016-0309-03.htm https://www.wosign.com/faq/faq2016-0309-04.htm http://blog.csdn. net/hherima/article/details/52469674 1: Introduction to SSL /TLS What is SSL and what is TLS? Officially said SSL is the secure sockets layer (se

SSL-TLS mutual authentication: MQTT mutual authentication between ESP8266 and mosquitto

Some references to this article: https://github.com/tuanpmt/esp_mqtt http://espressif.com/zh-hans/products/hardware/esp8266ex/overview foreword ESP8266 is a Wi-Fi chip with low power consumption, high integration and stable performance. It is the first choice for IoT development. Designed

SSL-TLS mutual authentication: MQTT mutual authentication based on mosquittto

Part of this article is referenced: https://baike.baidu.com/item/MQTT/3618851?fr=aladdin https://baike.baidu.com/item/mosquitto One: MQTT 1.1 Introduction to MQTTMQTT (Message Queuing Telemetry Transport, Message Queuing Telemetry Transport) is an instant messaging protocol developed by IB

[BLE] Introduction to ESP32 development and broadcasting

    About Tweets of the Day ​【Introduction to pit filling and broadcasting】 Affected by the chip price increase and out of stock recently, several batches of Bluetooth products of the company are looking for new directions, so I have recently studied the codes of several Bluetooth chips, mainly for applications, so I want to organize the Bluetooth o

ESP32 study notes (5) HTTP application

ESP32 study notes (5) HTTP application Note: The learning of this part needs to refer to the demo program under esp-idf : …\esp-idf\examples\protocols\esp_http_client 1. A brief introduction to HTTP HTTP–Hyper Text Transfer Protocol, is a stateless connection built on TCP. The entir

How to quickly restore IDEA's default shortcut keys

1. Find the IDEA keymaps folder and delete it 2. Create a new Windows copy file ending with xml , and copy the content: <keymap version="1" name="Windows copy" parent="$default"> <action id="CodeCompletion"> <keyboard-shortcut first-keystroke="alt slash" /> </ac

idea restore default shortcut keys

The computer I took over was changed to a job and the idea configuration was changed. The shortcut keys were all gone, and the default was restored when I got started. 1 Search and select keymap 2Select the default option, confirm

C# Get value of member variable based on string

If there is a value of a communication query variable, send a field to the opposite side, and return the corresponding value here, you can use the following code: using System; namespace ConsoleApplication1 { class A { public int high = 100; public string name = "

[.Net Core] Error "The asset file "project.assets.json" cannot be found when compiling .net core. Run NuGet package restore to generate this file" solution

foreword When migrating a .net core project from one server to another, when recompiling, it suddenly reported an error "Error NETSDK1004 Could not find the asset file "\obj\project.assets.json". Run NuGet package restore to generate this file ", because the package previously referenced in the project could not be found, the solution is as follows e

Solve the circular reference problem of MVC Json serialization / EF Json serialization circular reference problem---Newtonsoft.Json

1. Net open source Json serialization tool Newtonsoft.Json provides a solution to the circular reference problem of serialization: Method 1: Specify the Json serialization configuration as ReferenceLoopHandling.Ignore Method 2: Specify JsonIgnore to ignore reference objects Example 1, solve the Json serialization reference method of MVC: step1: Add a reference to the Newtonsof

JS component series - table component artifact: bootstrap table (2: parent-child table and row and column ordering)

Foreword: The last  JS component series - table component artifact: bootstrap table  briefly introduces the basic usage of Bootstrap Table, I did not expect the discussion to be quite lively. Some gardeners mentioned the usage of the parent-child table in the comments. Today, I will introduce its slightly more advanced usage in combination with the usage of the Bootstrap table

JS component series - table component artifact: bootstrap table

Foreword: I have been busy with various effects before, but I don't know that the most basic Bootstrap Table usage is not involved, sin, sin. Make it up today. In the morning, the blogger used the Bootstrap Table from scratch from beginning to end. He encountered many problems in use, and also made some notes, which are shared here for the reference of gardeners who need to us

JS component series - table component artifact: bootstrap table (3: final chapter, final dry goods welfare)

Foreword: I have introduced two articles about the basic usage of bootstrap table. In this chapter, we will continue to look at some of its more commonly used functions. Let’s end the article. Grandpa Mao told us that we must have a beginning and an end in doing things~~bootstrap table is something to think about. The function coverage seems unrealistic. The blogger has select