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• Ffmpeg screen tear

  8 mai 2021, par Cipher

  Screen tear issue in ffmpeg on manjaro linux, View this

  



  ffmpeg command used-
  
ffmpeg -y -f x11grab  -s 1366x768 -i :0.0  out.mkv

  



  ffmpeg -version  

ffmpeg version n4.2.2 Copyright (c) 2000-2019 the FFmpeg developers
built with gcc 9.3.0 (Arch Linux 9.3.0-1)
configuration: --prefix=/usr --disable-debug --disable-static --disable-stripping --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libdav1d --enable-libdrm --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libiec61883 --enable-libjack --enable-libmfx --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxml2 --enable-libxvid --enable-nvdec --enable-nvenc --enable-omx --enable-shared --enable-version3
libavutil      56. 31.100 / 56. 31.100
libavcodec     58. 54.100 / 58. 54.100
libavformat    58. 29.100 / 58. 29.100
libavdevice    58.  8.100 / 58.  8.100
libavfilter     7. 57.100 /  7. 57.100
libswscale      5.  5.100 /  5.  5.100
libswresample   3.  5.100 /  3.  5.100
libpostproc    55.  5.100 / 55.  5.100


  



  uname -a

Linux manjaro 5.4.2-1-MANJARO #1 SMP PREEMPT Thu Dec 5 09:55:57 UTC 2019 x86_64 GNU/Linux


  



  Desktop environment is Budgie

  


• Long-running AWS Linux process suddenly freezes once in a while

  12 décembre 2022, par Incredi Blame

  I am running a non-stop process on Ubuntu LTS AWS t2.micro instance. Process is ffmpeg downloading network stream from a CCTV. It crashes every 10 min cause of network errors, so I run it in a cycle script like this :

  


  while true
do
    ~command~
done


  


  The cycler-script itself never crashes.

  


  Everything works fine for hours (I check with ssh from time to time). But then sometimes ffmpeg process just freezes. I checked logs, it is writing the stream and it literally freezes mid-way through the stream, no error messages, nothing, as if it is still waiting for the next packet. Just stops working and never wakes up. Usually if the stream goes down ffmpeg complains, spits errors out and crashes. But on this occasion there is nothing and no crash either.

  


  Another mystery is that I run several of such ffmpeg processes and they all freeze at the same time.

  


  The issue with that freezing is the cycler can't restart ffmpegs, as they haven't crashed. When I check frozen processes with ps -aux they are shown as SL, which doesn't tell much, as they are always marked this way. top -i doesn't display them at all as active. When they work as normal it does. If I kill those frozen processes the cycler restarts them and everything works again as it should.

  


  I can always kill those ffmpegs once in a while on some schedule and let cycler restart them. Or check if they froze by timestamps they output and kill them then, so theoretically the problem is solvable. But I just want to know what causes it.

  


  I haven't figured out yet if this freezing happens at the same time of the day, trying to track that now. I don't think it could be related to free space shortage, as I have a cleaner cron job and free space is always available.

  


  So I have the following questions :

  


  

  1. Is there anything on AWS itself which could cause this freezing ? Like some kind of regular maintenance job that messes with running processes ?

  


  2. Could it be caused by Linux freezing long-running processes ? Probably not, as they all freeze at the same time while current running time is different for each.

  


  3. Last one, my cron job that cleans space also cleans out logs that ffmpeg is appending to. The script goes like this :

  


  


  tail "ffmpeg.log" -n 10000 > "tmp.log" && \
    cat "tmp.log" > "ffmpeg.log" && \
    rm "tmp.log"


  


  The logs now are already full and are never fully cleared. Cron job just preserves the last 10000 lines. It runs every 2 min and runs fine for hours. Could it be responsible for this sudden freezing due to some coincidental timing ?

  


  If none of the above is responsible for freezing it must be some streaming issue on the server side, which I have no access to. In that case I would have to rely on detecting freezing and restarting ffmpegs.

  


• Is it possible to merge 3 videos with ffmpeg by -f concat and crossfade without video content

  10 août 2019, par user3792705

  I want to merge 3 .mov files quickly without losing any resolution. I want to be able to distinguish the 3 pieces of videos after merge.

  "ffmpeg -f concat" does not lose resolution and quick without crossfade.

  But, I can’t distinguish 3 videos.

  As far as I know ffmpeg filter can be used add crossfade, but it have to use video start/end content to do the merger, which might involve transcoding. It won’t be fast compared with ’concat’, which won’t do transcoding, but simply copying.

  Here is the content (ffmpeg -i video.mov) of one of 3 videos :

  ffmpeg version 4.1.3 Copyright (c) 2000-2019 the FFmpeg developers
  
    built with Apple LLVM version 10.0.1 (clang-1001.0.46.3)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/4.1.3 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags='-I/Library/Java/JavaVirtualMachines/openjdk-12.jdk/Contents/Home/include -I/Library/Java/JavaVirtualMachines/openjdk-12.jdk/Contents/Home/include/darwin' --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame --enable-libopus --enable-librubberband --enable-libsnappy --enable-libtesseract --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-videotoolbox --disable-libjack --disable-indev=jack --enable-libaom --enable-libsoxr
  
    libavutil      56. 22.100 / 56. 22.100
  
    libavcodec     58. 35.100 / 58. 35.100
  
    libavformat    58. 20.100 / 58. 20.100
  
    libavdevice    58.  5.100 / 58.  5.100
  
    libavfilter     7. 40.101 /  7. 40.101
  
    libavresample   4.  0.  0 /  4.  0.  0
  
    libswscale      5.  3.100 /  5.  3.100
  
    libswresample   3.  3.100 /  3.  3.100
  
    libpostproc    55.  3.100 / 55.  3.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '..../(edited)/VMEK8375.MOV':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 0
  
      compatible_brands: qt  
  
      creation_time   : 2019-06-30T01:28:04.000000Z
  
      com.apple.quicktime.model: iPhone
  
      com.apple.quicktime.software: ZHIYUN
  
      com.apple.quicktime.creationdate: 2019-06-30T09:28:04Z
  
    Duration: 00:00:07.61, start: 0.000000, bitrate: 4386 kb/s
  
      Stream #0:0(und): Video: hevc (Main) (hvc1 / 0x31637668), yuv420p(tv, smpte170m/bt709/bt709), 1280x720, 4329 kb/s, 30.01 fps, 30 tbr, 600 tbn, 600 tbc (default)
  
      Metadata:
  
        creation_time   : 2019-06-30T01:28:04.000000Z
  
        handler_name    : Core Media Video
  
        encoder         : HEVC
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 94 kb/s (default)
  
      Metadata:
  
        creation_time   : 2019-06-30T01:28:04.000000Z
  
        handler_name    : Core Media Audio

  If I don’t care about crossfade with video content, just some ’nice’ black screen in between (It would be nice I add some text, like date + time on the black screen) is good enough for me. Is it possible to do ’concat’ and simple crossfade without video ’content’ ?