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• Frames grabbed from UDP H264 stream with ffmpeg are gray/distorded

  12 septembre 2019, par Clément Bourdarie

  I am grabbing frames from a udp h264 stream with Javacv’s FFMPEG on windows, and putting them into a JavaFX imageview. The problem is that most of the image isn’t received well (it is gray, distored...) :

  

  I used to have the same problem before and I made it work by using flush on the frame grabber after each frame, but I forgot to save my work and lost it, and this time the correction doesn’t work.

  Here’s the part where i configure/launch FFMPEG :

          final Java2DFrameConverter converter = new Java2DFrameConverter();
  
  
  
          // Show drone camera
  
          FFmpegFrameGrabber grabber = new FFmpegFrameGrabber("udp://227.0.0.1:2200");
  
  
  
          grabber.setFrameRate(_frameRate);
  
          grabber.setFormat(_format);
  
          grabber.setVideoBitrate(25000000);
  
          grabber.setVideoOption("preset", "ultrafast");
  
          grabber.setNumBuffers(0);
  
  
  
          grabber.start();
  
  
  
          // Grab frames as long as the thread is running
  
          while(_running){
  
                 final Frame frame = grabber.grab();
  
                 if (frame != null) {
  
                     final BufferedImage bufferedImage = converter.convert(frame);
  
                     if (bufferedImage != null) {
  
                           _cameraView.setImage(SwingFXUtils.toFXImage(bufferedImage, null));
  
                     }
  
                  }
  
                  Thread.sleep( 1000 / _frameRate );// don't grab frames faster than they are provided
  
                  grabber.flush();
  
          }
  
          _grabber.close();

  _format is "h264" and _frameRate is 30.

  Also, the system is flooded with prints like these (I’m not sure they are related to the problem though) :

  [h264 @ 00000000869c0a80] Invalid NAL unit 4, skipping.
  
  [h264 @ 00000000869c0a80] Invalid NAL unit 4, skipping.
  
  [h264 @ 00000000869c0a80] Invalid NAL unit 4, skipping.
  
  [h264 @ 00000000869c0a80] Reference 6 >= 4
  
  [h264 @ 00000000869c0a80] error while decoding MB 115 14, bytestream 1979
  
  [h264 @ 00000000869c0a80] concealing 6414 DC, 6414 AC, 6414 MV errors in P frame
  
  [h264 @ 0000000078f81180] Invalid NAL unit 0, skipping.
  
  [h264 @ 0000000078f81180] Invalid NAL unit 0, skipping.
  
  [h264 @ 0000000078f81180] concealing 4811 DC, 4811 AC, 4811 MV errors in B frame

  I don’t understand why it doesn’t work anymore

• need to loop and convert the files

  24 décembre 2020, par AUDICOM

  My script should work as follows :
Check whether or not there are DAV files in the folder, if there are NO elements for a 1 minute loop until the next check, and if there are any DAV files, it should trigger DAV to JPEG conversion and move JPEGs to the SNAPSHOT folder, and DAV for PROCESSED folder. Until it works, the problem is finishing the conversion to JPEG and moving the files to folders, it closes the script, and it goes back to the loop and waits for a new file, this is not happening.

  


  Another problem is also that the files are generated every 30 minutes in bulk, but they already appear in bulk and therefore end when the 30 minutes are over, or the problem is when the script ends or the script just moves to one. PROCESSED folder, and does not convert.

  


  Script :

  


  REM -  - Checks for New Files (*.DAV).

:LOOP01    
     IF EXIST "C:\Users\AudicomRede\Documents\SNAPSHOT FINAL\TESTE VERIFICAÇÃO\*.*" GOTO SKIP01


:LOOP02
     IF NOT EXIST "C:\Users\AudicomRede\Documents\SNAPSHOT FINAL\TESTE VERIFICAÇÃO" GOTO SKIP02

     REM - ALL THIS WILL BE DONE IF THE DAV FILE EXISTS
:
:
:SKIP01
    REM Crafty 1 minute delay...
       PING 1.1.1.1 -n 10 -w 6000 >NUL
           GOTO LOOP01
:
:
:SKIP02
    REM START CONVERT
       for %%A IN (*.dav) do (

            ffmpeg -i "%%A" -r 0.2 -bt 20M -s 480x300 "%%~nA"%%03d.jpg

                  Move "%%A" PROCESSED
                      Move "*.*" SNAPSHOT 
                          
)

 GOTO SKIP01


  


  I use FFMPEG to convert all files.

  


• Evolution #2269 : Prise en compte des variantes d’une langue

  31 août 2011, par cedric -

  il est deja possible de gérer des langues dérivées : dans ton exemple ce serait fr_ca. Il y a le cas existant du pt_br (portugais du brésil). Mais il est un fait qu’actuellement, si la lange n’existe pas en pt_br on se rabat sur la langue du site ou le fr au final, sans forcément chercher dans pt (...)