Recherche avancée

Sur d’autres sites (7886)

• Reading images from AXIS ip camera using OpenCV

  14 juin 2016, par batuman

  I am trying to access AXIS IP camera from my program using OpenCV.
  My OpenCV version is 3.1. I follow this tutorial link.

  I have all libraries installed.
  My following program can load mp4 video successfully. That means ffmpeg and necessary libraries are working fine.

  #include <iostream>
  
  #include <opencv2></opencv2>opencv.hpp>
  
  
  
  using namespace std;
  
  int main() {
  
      cv::VideoCapture vcap("test.mp4");
  
      cv::Mat image;
  
  //    const string address = "rtsp://root:pass@192.168.0.90/axis-media/media.amp?camera=1";
  
  //    if(!vcap.open(address)){
  
  //      std::cout &lt;&lt; "Error opening video stream or file " &lt;&lt; std::endl;
  
  //      return -1;
  
  //    }
  
      for(;;){
  
          if(!vcap.read(image)){
  
              std::cout &lt;&lt; "No frame" &lt;&lt; std::endl;
  
              cv::waitKey(0);
  
          }
  
          cv::imshow("Display", image);
  
          cv::waitKey(1);
  
      }
  
      return 0;
  
  }
  
  </iostream>

  When I tried to access the IP Camera as follow

  cv::VideoCapture vcap("rtsp://root:pass@192.168.0.90/axis-media/media.amp?camera=1");

  I have the following error

  GStreamer Plugin: Embedded video playback halted; module source reported: Could 
  
  not open resource for reading and writing.
  
  OpenCV Error: Unspecified error (GStreamer: unable to start pipeline
  
  ) in cvCaptureFromCAM_GStreamer, file /home/Softwares/opencv/opencv/modules
  
  /videoio/src/cap_gstreamer.cpp, line 818
  
  terminate called after throwing an instance of 'cv::Exception'
  
    what():  /home/Softwares/opencv/opencv/modules/videoio/src/cap_gstreamer.
  
  cpp:818: error: (-2) GStreamer: unable to start pipeline
  
   in function cvCaptureFromCAM_GStreamer

  User is root and password is pass and ip 192.168.0.90 are all defaults.

  My if config gave me

  ifconfig
  
  eth0      Link encap:Ethernet  HWaddr b8:2a:72:c6:b8:13  
  
            inet6 addr: fe80::ba2a:72ff:fec6:b813/64 Scope:Link
  
            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
  
            RX packets:723959 errors:0 dropped:0 overruns:0 frame:0
  
            TX packets:116637 errors:0 dropped:0 overruns:0 carrier:0
  
            collisions:0 txqueuelen:1000 
  
            RX bytes:199422245 (199.4 MB)  TX bytes:13701699 (13.7 MB)
  
  
  
  lo        Link encap:Local Loopback  
  
            inet addr:127.0.0.1  Mask:255.0.0.0
  
            inet6 addr: ::1/128 Scope:Host
  
            UP LOOPBACK RUNNING  MTU:65536  Metric:1
  
            RX packets:24829 errors:0 dropped:0 overruns:0 frame:0
  
            TX packets:24829 errors:0 dropped:0 overruns:0 carrier:0
  
            collisions:0 txqueuelen:0 
  
            RX bytes:2502903 (2.5 MB)  TX bytes:2502903 (2.5 MB)
  
  
  
  wlan0     Link encap:Ethernet  HWaddr a0:a8:cd:99:92:60  
  
            UP BROADCAST MULTICAST  MTU:1500  Metric:1
  
            RX packets:0 errors:0 dropped:0 overruns:0 frame:0
  
            TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
  
            collisions:0 txqueuelen:1000 
  
            RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

  What could be the problem for this access to the camera ?

  Thanks

• FFmpeg doesn't produce a 'progress' event when converting to videos of certain file types

  10 décembre 2023, par Alteria

  I am writing an app in electron, and one of the functionalities is that you can create a copy of the currently selected file with a different type. I do this by having a dropdown in the html that allows you to select the type. I then use a function in preload.js that calls an ffmpeg function in main.js

  


  Preload :

  


  const { contextBridge, ipcRenderer } = require('electron')

contextBridge.exposeInMainWorld('changeFiles', {
    //This is the function that is called
    convert: (filePath, newFormat) => ipcRenderer.send('change:file:convert-format', filePath, newFormat)
})


  


  Main :

  


  //electron
const { app, BrowserWindow, ipcMain} = require('electron')

//node
const path = require('path')


//ffmpeg setup
const ffmpegStatic = require('ffmpeg-static')
const ffmpeg = require('fluent-ffmpeg')
ffmpeg.setFfmpegPath(ffmpegStatic)

//imports an array that has video formats ['.mp4', '.webm', '.avi'] and so on
const { videoFormat } = require('./file formats.js')

//Preload sends to this
ipcMain.on('change:file:convert-format', (_event, filePath, newFormat) => {
    //There is an if statement to another function because I want to be able to convert images in the future
    if(videoFormats.includes(newFormat)) {
        videoConvert(filePath, newFormat, _event)
        return
    }
})

const videoConvert = (file, newFormat, _event) => {
    //file is the filepath for the file you want to change

    ffmpeg()
        .input(file)
        .saveToFile(`${path.resolve(path.dirname(file), path.parse(file).name + newFormat)}`)
        .on('progress', (progress) => {
             console.log(progress)
        })
        .on('error', (error) => {
            console.log(error)
        })
}



  


  For some reason, when the format for the video is '.mp4', the .on('progress') fires, but if the format is '.webm' or '.avi' then it is not fired. There are also some issues I have noticed, where if these formats are chosen, then the files may partially be copied over to the new file.

  


  I don't know if this is because of how I am handling this, a mistake I have made in the .saveToFile(), or something else. No part of this code produces any errors anywhere, the only errors being that the progress doesn't fire and that the files are not always copied over correctly into the new format.

  


  What should I do ?

  


• ffmpeg Image generation output results

  25 juillet 2020, par Joel Holmes

  I'm using FFMPEG to generate images from a video. I'd like to know the output names when the images are generated as a stream so I can upload them to s3 as they are generated.

  



  ffmpeg -i video.mp4 -vf scale=800:-1 -vsync 0 output/thumbnail-%06d.png


  



  The standard out is a bunch of video information but I'd like to know the generated file names if possible.