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• I'm running a process in Java and am getting stuck when I wait for it to finish

  31 juillet 2020, par nottAbott

  I have a Java program that is supposed to make copies of segments of a video and then stitch them back together, using ffmpeg. My "snip" method, the one that makes the segment files, has a problem, it gets stuck when I call "process.waitfor()". When I take it out, the videos load partly, but cannot be accessed until I close the program. When I try to delete them, while the program is running, it says that they cannot be deleted because they are in use. Could anyone lead me in the right direction ? Here is the method :

  


  //snips out all the clips from the main video
public void snip() throws IOException, InterruptedException {
    
    for(int i = 0; i < snippets.size(); i++) {
        //Future reference: https://stackoverflow.com/questions/9885643/ffmpeg-executed-from-javas-processbuilder-does-not-return-under-windows-7/9885717#9885717
        //Example: ffmpeg -i 20sec.mp4 -ss 0:0:1 -to 0:0:5 -c copy foobar.mp4
        String newFile = "foobar" + String.valueOf(i) + ".mp4";
        ProcessBuilder processBuilder = new ProcessBuilder("ffmpeg", "-i", videoName, "-ss",
                snippets.get(i).getStartTime(), "-to", snippets.get(i).getEndTime(), newFile);
        
        //I tried this first and then added in the process/process.waitfor below
        //processBuilder.start();
        
        Process process = processBuilder.start();
        process.waitFor();
        
        System.out.println("Snip " + i + "\n");
        
        //add to the formatted list of files to be concat later
        if(i == snippets.size() - 1) {
            stitchFiles += newFile + "\"";
        }
        
        else {
            stitchFiles += newFile + "|";
        }
    }
}


  


• lavf/srt : fix build fail when used the libsrt 1.4.1

  12 juillet 2020, par Jun Zhao

  lavf/srt : fix build fail when used the libsrt 1.4.1
  libsrt changed the :
  
  SRTO_SMOOTHER   -> SRTO_CONGESTION
  
  SRTO_STRICTENC  -> SRTO_ENFORCEDENCRYPTION
  
  and removed the front of deprecated options (SRTO_SMOOTHER/SRTO_STRICTENC)
  
  in the header, it's lead to build fail
  fix #8760
  Signed-off-by : Jun Zhao <barryjzhao@tencent.com>
  

  • [DH] libavformat/libsrt.c

• ffmpeg to kurento rtp stream choppy video issue

  29 juillet 2020, par ahmetsarias

  I use ffmpeg to make an rtp stream to kurento media server and then send it to browsers via webrtc.

  


  ffmpeg (h264 RTP) -> Kurento -> (h264 WebRTC) Browser

  


  I'm capturing virtual xorg display.
This is my ffmpeg command :

  


  ffmpeg -y -v info -fflags +genpts -f x11grab -draw_mouse 0 -r 25 -s 1280x720 -thread_queue_size 4096 -i :0.0+0,0 -an -c:v libx264 -preset veryfast -crf 25 -g 50 -pix_fmt yuv420p -maxrate 2976k -bufsize 5952k -ssrc 112233 -payload_type 103 -tune zerolatency -f rtp rtp://172.16.1.115:40258

  


  This is my fake sdp offer used in negotiation with kurento RtpEndpoint

  


  v=0
o=- 0 0 IN IP4 127.0.0.1
s=Stream
c=IN IP4 127.0.0.1
t=0 0
m=video 9 RTP/AVP 103
a=rtpmap:103 H264/90000
a=fmtp:103 packetization-mode=1
a=sendonly
a=direction:active
a=ssrc:112233 cname:user@example.com 


  


  Here is the problem :

  


  Some I-frames are choppy on bottom half slice of the frame while others have no problem.

  


  It is sometimes corrected when another I-frame has arrived, but mostly choppy.

  


  When choppiness happened, Kms log says :

  


  


  kmsutils kmsutils.c:483:gap_detection_probe:kmsagnosticbin2-108:sink Stream gap detected, timestamp : 0:51:22.574766908, duration : 0:00:00.000008237

  


  


  Normal stream (No choppy at all)

  


  

  


  Choppy stream

  


  

  


  When it is corrected with an I-Frame (Sometimes it happens)

  


  

  


  I have no clue about what could lead the issue.

  


  Things that I tried to solve the problem.

  


  

  • Adding ?pkt_size=1000 (1100,900,1200. Since the mtu in kurento is 1200 default)

  


  • Changing -crf to different values in between 18-35

  


  • Changing -preset between medium and ultrafast

  


  • Changing framerate

  


  • Changing gop length (When i lower the gop length -More I-Frames- choppiness become shorter in duration but more frequent)

  


  • When I disable sliced-threads, there is no issue with bottom side but whole screen freezes in same scenario

  


  


  Any help would be appreciated. Thanks.