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• (no accepted answer) How to merge 2 overlapping videos into one video using ffmpeg or opencv ?

  3 janvier 2021, par Muhammad Umer

  Merging two videos is easy, been answered couple of times. What I have is multiple overlapping videos. A video might have overlaps with video before it. Meaning if video 1 covers 1-5 timeline then video 2 may overlap 1, and cover 3 to 8. Merging them as is would result in 1-5|3-8, when i need 1-8 only.

  



  Videos are alphabetically sorted.

  



  My general idea of solution is...

  



  

  • grab last frame of the video

  


  • if it's first video continue

  


  • if it's not first video, ie. 2nd, search for frame saved in previous steps frame by frame

  


  • if it reaches to last frame of current video then there is no overlap continue

  


  • if it founds a frame then clip 2nd video up to that frame inclusive and then go to next frame

  


  • once all videos have been analyzed, merge them into one video.

  


  



  I need to translate this to ffmpeg commands. Or opencv if that's a better tool.

  



  If there is better way of doing that, I'm interested in that too.

  


• Stream h264 to javafx possibly using javacv/ffmpeg

  4 octobre 2018, par cagney

  I’m really stuck on getting a video stream to play on a java fx project.

  — Short version :

  I’m streaming h264/avcc flavor video from an android phone to a desktop computer. However javafx doesn’t have an easy solution for displaying stream. I’m attempting to use javacv / ffmpeg in an attempt to make this work. However I am getting errors from ffmpeg.

  1) Is there a better way to display streaming video on javafx ?

  2) Do you have a sample project or good tutorial for javacv ffmpegframegrabber ?

  3) I think I may be missing some small detail in mycode but Im not sure what i would be.

  — Longer Version :

  1) On the android end Im getting video using mediarecorder. In order to get the sps/pps info I record and save a small movie to the device and then parse the sps and pps data.

  2) Next, on the android, I split up the nalus to meet MTU req and send them over a udp connection to my desktop

  3)On my desktop I reassmble the nalus( or trash them if they loose data) and feed those to an input stream that I gave to the framegreabber constructor.

  — The Code and Logs :

  The errors are long and numerous depending on the flavor I feed it. Here are two separate examples which are usually repeated at great length

  [h264 @ 0000020225907a40] non-existing PPS 0 referenced
  
  [h264 @ 0000020225907a40] decode_slice_header error
  
  [h264 @ 0000020225907a40] no frame!
  
  
  
  [h264 @ 00000163d8637a40] illegal aspect ratio
  
  [h264 @ 00000163d8637a40] pps_id 3412 out of range
  
  [AVBSFContext @ 00000163e28a0e00] Invalid NAL unit 0, skipping.

   !! One big caveat that I am aware off is that I have not implemented timestamps
  which I created on the android device when feeding ffmpeg. I think it should still show distorted images without this though

  Because I have spent all day guessing and trying I have several "flavors" of data I have shoved through. I am only showing the first section of each nal which I believe if correct would at least show a garbage image as long as my sps and pps are right

  sps: 67 80 80 1E E9 01 68 22 FD C0 36 85 09 A8
  
  pps: 68 06 06 E2

  Below is annex B style.
  These were each prefixed with either 00 00 01 and 00 00 00 01

  Debug transfer 65 B8 40 0B E5 B8 7B 80 5B 85 
  
  Debug transfer 41 E2 20 7A 74 34 3B D6 BE FA 
  
  Debug transfer 41 E4 40 2F 01 E0 0C 06 EE 91 
  
  Debug transfer 41 E6 60 3E A1 20 5A 02 3C 6D 
  
  Debug transfer 41 E8 80 13 B0 B9 82 C3 03 F4 
  
  Debug transfer 41 EC C0 1B A3 0C 28 F1 B0 C8 
  
  Debug transfer 41 EE E0 1F CE 07 30 EE 05 06 
  
  Debug transfer 41 F1 00 08 ED 80 9C 20 09 73 
  
  Debug transfer 41 F3 20 09 E9 00 86 60 21 C3 
  
  VideoDecoderaddPacket type: 24
  
  Debug transfer 67 80 80 1E E9 01 68 22 FD C0 
  
  Debug transfer 68 06 06 E2 
  
  Debug transfer 65 B8 20 00 9F 80 78 00 12 8A 
  
  Debug transfer 41 E2 20 09 F0 1E 40 7B 0C E0 
  
  Debug transfer 41 E4 40 09 F0 29 30 D6 00 AE 
  
  Debug transfer 41 E6 60 09 F1 48 31 80 99 40 
  
  [h264 @ 000001c771617a40] non-existing PPS 0 referenced

  Here I tried Avcc style. You can see the first line is the combination of the sps pps followed by idr and then repeated non idr

  Debug transfer 18 00 0E 67 80 80 1E E9 01 68 
  
  Debug transfer 00 02 4A 8F 65 B8 20 00 9F C5 
  
  Debug transfer 00 02 2F DA 41 E2 20 09 E8 0F 
  
  Debug transfer 00 02 2C 34 41 E4 40 09 F4 20 
  
  Debug transfer 00 02 4D 92 41 E6 60 09 FC 2B 
  
  Debug transfer 00 02 47 02 41 E8 80 09 F0 72 
  
  Debug transfer 00 02 52 50 41 EA A0 09 EC 0F 
  
  Debug transfer 00 02 58 8A 41 EC C0 09 FC 6F 
  
  Debug transfer 00 02 55 F9 41 EE E0 09 FC 6E 
  
  Debug transfer 00 02 4D 79 41 F1 00 09 F0 3E 
  
  Debug transfer 00 02 4D B6 41 F3 20 09 E8 64 

  The following class is where I try to get javacv/ffmpeg to show the video. I dont think its an ideal solution and am researching canvasfram as a replacement to the image view.

      public class ImageDecoder {
  
  
  
      private final static String TAG = "ImageDecoder ";
  
  
  
      private ImageDecoder(){
  
  
  
      }
  
  
  
  
  
      public static void streamImageToImageView(
  
              final ImageView view,
  
              final InputStream inputStream,
  
              final String format,
  
              final int frameRate,
  
              final int bitrate,
  
              final String preset,
  
              final int numBuffers
  
      )
  
      {
  
          System.out.println("Image Decoder Starting...");
  
  
  
  
  
          try(    final FrameGrabber grabber = new 
  
      FFmpegFrameGrabber(inputStream))
  
          {
  
  
  
              final Java2DFrameConverter converter = new Java2DFrameConverter();
  
  
  
              grabber.setFrameNumber(frameRate);
  
              grabber.setFormat(format);
  
              grabber.setVideoBitrate(bitrate);
  
              grabber.setVideoOption("preset", preset);
  
              grabber.setNumBuffers(numBuffers);
  
  
  
              System.out.println("Image Decoder waiting on grabber.start...");
  
              grabber.start();   //---- this call is blocking the loop
  
  
  
              System.out.println("Image Decoder Looping--------------------------- 
  
     -------- hit stop");
  
              while(!Thread.interrupted()){
  
                  //System.out.println("Image Decoder Looping");
  
                  final Frame frame = grabber.grab();
  
                  if (frame != null){
  
                      final BufferedImage bufferedImage = 
  
      converter.convert(frame);
  
                      if (bufferedImage != null){
  
  
  
                          Platform.runLater(() -> 
  
      view.setImage(SwingFXUtils.toFXImage(bufferedImage, null)));
  
                      }else{
  
                          System.out.println("no buf im");
  
                      }
  
                  }else{
  
                      System.out.println("no fr");
  
                      Thread.currentThread().interrupt();
  
                  }
  
  
  
              }
  
  
  
  
  
  
  
          }catch (Exception e){
  
              System.out.print(TAG + e);
  
          }
  
  
  
  
  
      }
  
  
  
  
  
  
  
  
  
  
  
  
  
      }

  Any help is greatly appreciated.

• Evolution #2546 : Cohérance : confirmer le mot de passe lors du changement

  13 mai 2013, par Gilles VINCENT

  A mon avis, il est plus naturel d’avoir une double saisie et un mécanisme en temps réel qui dit si les deux sont identiques (avec pourquoi pas un mécanisme de contrôle de la complexité du mot de passe). Le fait de penser changer son mot de passe en A, de se planter plusieurs fois parce qu’on aura mis B, puis penser à redemander son mot de passe, aller sur son mail pour retourner sur le même formulaire, c’est quand même beaucoup plus fastidieux.