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• pyav / ffmpeg / libav access side data without decoding the video

  19 juin 2021, par user1315621

  Right now I am accessing the motion vectors in the following way :

  


  container = av.open(
    rtsp_url, 'r',
    options={
        'rtsp_transport': 'tcp',
        'stimeout': '5000000',  
        'max_delay': '5000000', 
    }
)
stream = container.streams.video[0]
codec_context = stream.codec_context
codec_context.export_mvs = True


for packet in container.demux(video=0):
    for video_frame in packet.decode():
        motion_vectors_raw = video_frame.side_data.get('MOTION_VECTORS')


  


  It seems to me that this does decode the video_frame. Is there a way to obtain the motion vectors without having to decode the entire frame ? My goal is to reduce the CPU utilization.

  


• FFmpeg does not successfully send http request to server

  20 octobre 2019, par e-ly

  I’m trying to output data from ffmpeg to my webserver, but it simply does not work when I use my domain. It works as expected when I use localhost but not when I use my domain.

  I’ve tried multiple things such as changing from a subdomain to a subdirectory using nginx, and like I said— it works when I use localhost but not when I use my domain. When I ran -v trace the logs told me that the connection was successful but the server did not receive anything, yet when I visited the same url in my browser I got a response.

  ffmpeg command :

  '-v', 'trace',                                               
  
  '-f', 'x11grab',
  
  '-s', '720x480',
  
  '-r', '30',
  
  '-i', ':100',
  
  '-an',
  
  '-c:v', 'mpeg1video',
  
  '-q:v', '12',
  
  '-bf', '0',
  
  '-f', 'mpegts',
  
  'http://stream.domain.com/'                                                                                                    

  Nginx rule :

  server {
  
     listen 80;
  
     server_name stream.domain.com;
  
     location / {
  
         proxy_pass http://localhost:9000/;
  
     }
  
  }    

  Nodejs code :

  app.post('/', (req, res) => {
  
      console.log('Post received', req.url, req.ip)
  
      res.sendStatus(200)
  
  })

  I expect the console of the node process to let me know that a post has been received (for debugging purposes)
  Instead, nothing is received.
  However using http://localhost:9000/ instead of http://stream.domain.com/ works as expected

• Unable to access user selected file via NSOpenPanel in FFMPEG process in macOS app

  12 décembre 2019, par Raptor

  I am new to macOS development via SwiftUI. I’m trying to run a FFMPEG process after I selected a MP4 file via NSOpenPanel. However, the FFMPEG responded with :

  file :///Users/MyUsername/Documents/Video.mp4 : No such file or directory

  Here is my simple codes :

  import SwiftUI
  
  
  
  struct ContentView: View {
  
  
  
      @State var selectedURL: URL?
  
  
  
      var body: some View {
  
          VStack {
  
              if selectedURL != nil {
  
                  Text("Selected: \(selectedURL!.absoluteString)")
  
              } else {
  
                  Text("Nothing selected")
  
              }
  
              Button(action: {
  
                  let panel = NSOpenPanel()
  
                  panel.allowedFileTypes = ["mp4"]
  
                  panel.canChooseDirectories = false
  
                  panel.canCreateDirectories = false
  
                  panel.allowsMultipleSelection = false
  
                  let result = panel.runModal()
  
                  if result == .OK {
  
                      self.selectedURL = panel.url
  
  
  
                      let savePath = self.getDownloadDirectory().appendingPathComponent("video.webm")
  
  
  
                      self.convertVideo(inputFilePath: self.selectedURL!.absoluteString, outputFilePath: savePath.absoluteString, callback: {(s) in
  
                          // omit the callback at this moment
  
                      })
  
                  }
  
              }) {
  
                  Text("Select File")
  
              }
  
          }
  
          .frame(width: 640, height: 480)
  
      }
  
  
  
      func getDownloadDirectory() -> URL {
  
          let paths = FileManager.default.urls(for: .downloadsDirectory, in: .userDomainMask)
  
          return paths[0]
  
      }
  
  
  
      func convertVideo(inputFilePath: String, outputFilePath: String,
  
                       callback: @escaping (Bool) -> Void) -> (Process, DispatchWorkItem)? {
  
          guard let launchPath = Bundle.main.path(forResource: "ffmpeg", ofType: "") else {
  
              return nil
  
          }
  
          let process = Process()
  
          let task = DispatchWorkItem {
  
              process.launchPath = launchPath
  
              process.arguments = [
  
                  "-y",
  
                  "-i", inputFilePath,
  
                  "-vcodec", "vp8",
  
                  "-acodec", "libvorbis",
  
                  "-pix_fmt", "yuva420p",
  
                  "-metadata:s:v:0",
  
                  "alpha_mode=\"1\"",
  
                  "-auto-alt-ref", "0",
  
                  outputFilePath
  
              ]
  
              process.standardInput = FileHandle.nullDevice
  
              process.launch()
  
              process.terminationHandler = { process in
  
                  callback(process.terminationStatus == 0)
  
              }
  
          }
  
          DispatchQueue.global(qos: .userInitiated).async(execute: task)
  
  
  
          return (process, task)
  
      }
  
  }

  What did I miss to allow FFMPEG process to access my selected file ? Thanks !