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• Create and combine a blank video stream with a subtitle steam

  10 décembre 2014, par CPO

  I have a live .ts stream that contains a video stream, audio stream and subtitle stream. What I want to do is to display the video in full, eg video and audio and subtitles, but in parallel take the same stream and ’blank’ the video to black, but allow the subtitle stream to be rendered into that video stream for display separately from the fully displayed streams. The reason for this is to allow the subtitles to be displayed separately and cropped,from a second projector, but to have a black backgroung to avoid distractions when there is no subtitle present. I believe this can be achieved using FFMPEG but my limited experience with this utility rather limits my progress. I believe that the blanked video stream needs to be the same frame rate and resolution as the original in order that the rendered subtitles stay in synch with the original video stream. Any help or suggestions warmly welcomed. Thank you

• FFmpeg generated video length doesn't match expected length [on hold]

  21 juin 2018, par BentCoder

  I am using command below to generate video out of images. The problem is the length out the video generated. It is always 5 seconds less than expected. If I have 4 images, I expect to see 20 seconds of video but I am getting 15 seconds instead. The very last image img-03.jpg just appears at the end of the video as if it is a cover image. Any idea why and solution ?

  Command

  ffmpeg -y -framerate 1/5 -f image2 \
  
  -i img-%2d.jpg \
  
  -c:v libvpx-vp9 \
  
  -r 25 \
  
  -crf 30 -b:v 0 \
  
  video.webm

  Images

  img-00.jpg
  
  img-01.jpg
  
  img-02.jpg
  
  img-03.jpg

  Output

  ffmpeg version 3.2.10-1~deb9u1~bpo8+1 Copyright (c) 2000-2018 the FFmpeg developers
  
    built with gcc 4.9.2 (Debian 4.9.2-10)
  
    configuration: --prefix=/usr --extra-version='1~deb9u1~bpo8+1' --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --disable-libebur128 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  
    libavutil      55. 34.101 / 55. 34.101
  
    libavcodec     57. 64.101 / 57. 64.101
  
    libavformat    57. 56.101 / 57. 56.101
  
    libavdevice    57.  1.100 / 57.  1.100
  
    libavfilter     6. 65.100 /  6. 65.100
  
    libavresample   3.  1.  0 /  3.  1.  0
  
    libswscale      4.  2.100 /  4.  2.100
  
    libswresample   2.  3.100 /  2.  3.100
  
    libpostproc    54.  1.100 / 54.  1.100
  
  Input #0, image2, from 'img-%2d.jpg':
  
    Duration: 00:00:20.00, start: 0.000000, bitrate: N/A
  
      Stream #0:0: Video: mjpeg, yuvj444p(pc, bt470bg/unknown/unknown), 854x480 [SAR 1:1 DAR 427:240], 0.20 fps, 0.20 tbr, 0.20 tbn, 0.20 tbc
  
  [swscaler @ 0x55f2af60e800] deprecated pixel format used, make sure you did set range correctly
  
  [libvpx-vp9 @ 0x55f2af6276a0] v1.3.0
  
  Output #0, webm, to 'video.webm':
  
    Metadata:
  
      encoder         : Lavf57.56.101
  
      Stream #0:0: Video: vp9 (libvpx-vp9), yuv420p, 854x480 [SAR 1:1 DAR 427:240], q=-1--1, 25 fps, 1k tbn, 25 tbc
  
      Metadata:
  
        encoder         : Lavc57.64.101 libvpx-vp9
  
      Side data:
  
        cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (mjpeg (native) -> vp9 (libvpx-vp9))
  
  Press [q] to stop, [?] for help
  
  Input stream #0:0 frame changed from size:854x480 fmt:yuvj444p to size:854x480 fmt:yuvj420p
  
  [swscaler @ 0x55f2af602b60] deprecated pixel format used, make sure you did set range correctly
  
  frame=    4 fps=0.0 q=0.0 Lsize=     214kB time=00:00:15.00 bitrate= 117.0kbits/s speed=  16x    
  
  video:214kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.234810%

• Révision 20977 : ecrire/public/composer.php, ecrire/public/assembler.php : report de r17975 et r1...

  16 novembre 2013, par guytarr °