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• Variable size for ffmpeg filter

  15 novembre 2013, par DrakaSAN

  I am creating a bunch of script to easily use ffmpeg.

  All my scripts now work, but a lot of value are hardcoded, which make them wanting exact size for the video (854x240, size of my tests videos)

  A good example is better than long explanation :

  ffmpeg -i 0.mp4 -vf "
  
  scale=854/2:-1 [low];
  
  color=c=black@1.0:s=854x240:r=29.97:d=30.0 [bg];
  
  movie=1.mp4, scale=854/2:-1 [high];
  
  [bg][high] overlay=0:0 [bgh];
  
  [bgh][low] overlay=854/2:-1" leftright.mp4

  It take 0.mp4 and 1.mp4 and put them side by side in the same video. But the dimension value are hardcoded. But it work.

  I know I can use iw and ih as "input width" and "input height" for the first scale filter, but when I try to put anything else as dimension for the color background, it just throw me a error :

  Unable to parse option value "iw:ih" as image size
  
  Unable to parse option value "iw:240" as image size
  
  Unable to parse option value "860*2:240" as image size

  and I end up to put 1720x240 again, which is really bad.

  Is there a way to bypass this, or to put input-dependent value ?

  Edit :

  Starting with video 1.mp4 (854x240) and 2.mp4 (520x520) (example value), put them side by side in out.mp4 (which in this case will have the dimension max(height)x(2xmax(width)), so in this case 854x1040), with black background.

    ax
  
  <---->
  
  .____.^
  
  |    ||
  
  |  1 ||
  
  |    ||ay
  
  |    ||
  
  |____|V
  
  
  
      bx
  
  <-------->
  
  .________.^
  
  |   2    ||by
  
  |________|V

  Will end up as

  ay>ax
  
  bx>by
  
  
  
      bx        bx
  
  <--------><-------->
  
  xx.____.xxxxxxxxxxxx^
  
  xx|    |xxxxxxxxxxxx|
  
  xx|  1 |xx.________.|
  
  xx|    |xx|    2   ||ay
  
  xx|    |xx|________||
  
  xx|____|xxxxxxxxxxxxV

• FFMpeg to resize any video to fit 1080x1920 vertical, without cropping, instead by shrinking and adding blurred borders ?

  19 mars 2021, par Max

  I found some posts explaining how to turn any video horizontal by adding blurred borders using FFMpeg, but I want to convert videos to vertical 1080x1920. I don't want it to enlarge the video, nor crop if a dimension is bigger than either 1080 or 1920 dimension. Instead, I want it to shrink the video until it fits fully inside 1080x1920, and then I want it to add blurred borders to the empty areas.

  


  This is the snippet I found, but when I tried reversing the numbers, it actually cropped the video.

  


  ffmpeg -I input.mp4 -lavfi "[0:v]scale=1920*2:1080*2,boxblur=luma_radius=min(h\,w)/20:luma_power=1:chroma_radius=min(cw\,ch)/20:chroma_power=1[bg];[0:v]scale=-1:1080[ov];[bg][ov]overlay=(W-w)/2:(H-h)/2,crop=w=1920:h=1080" output.mp4

  


• "No Java virtual machine has been registered" error when using "mediacodec"

  12 septembre 2018, par Mohammed_BEY

  I successfully cross-compiled FFmpeg with "mediacodec" (developed in Java) library for aarch64 ARM architecture under Android OS.
  When I try to run FFmpeg on Android without "mediacodec", it works just fine.
  However, when I run it with "mediacodec" option I got an error :
  "No Java virtual machine has been registered"
  Here is the command line I used :
  ./ffmpeg -vcodec hevc_mediacodec -i jellyfish-20-mbps-hd-hevc.mkv -f null out.null

  1) is is the problem of JRE ?
  2) if so, could someone guide me to enable JRE on Android, or cross-compile it ?

  Actually, I tried many times to cross-compile "openjdk" for aarch64 but none works.