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• Revision 7066 : suite de suppression des champs pros

  3 novembre 2012, par kent1 — Log

  suite de suppression des champs pros

• Metal Gear Solid VP3 Easter Egg

  4 août 2011, par Multimedia Mike — Game Hacking

  Metal Gear Solid : The Twin Snakes for the Nintendo GameCube is very heavy on the cutscenes. Most of them are animated in real-time but there are a bunch of clips — normally of a more photo-realistic nature — that the developers needed to compress using a conventional video codec. What did they decide to use for this task ? On2 VP3 (forerunner of Theora) in a custom transport format. This is only the second game I have seen in the wild that uses pure On2 VP3 (first was a horse game). Reimar and I sorted out most of the details sometime ago. I sat down today and wrote a FFmpeg / Libav demuxer for the format, mostly to prove to myself that I still could.

  Things went pretty smoothly. We suspected that there was an integer field that indicated the frame rate, but 18 fps is a bit strange. I kept fixating on a header field that read 0x41F00000. Where have I seen that number before ? Oh, of course — it’s the number 30.0 expressed as an IEEE 32-bit float. The 4XM format pulled the same trick.

  Hexadecimal Easter Egg
  I know I finished the game years ago but I really can’t recall any of the clips present in the samples directory. The file mgs1-60.vp3 contains a computer screen granting the player access and illustrates this with a hexdump. It looks something like this :

  
  
  

  Funny, there are only 22 bytes on a line when there should be 32 according to the offsets. But, leave it to me to try to figure out what the file type is, regardless. I squinted and copied the first 22 bytes into a file :

   1F 8B 08 00   85 E2 17 38   00 03 EC 3A   0D 78 54 D5
   38 00 03 EC   3A 0D
  

  And the answer to the big question :

  $ file mgsfile
  mgsfile : gzip compressed data, from Unix, last modified : Wed Oct 27 22:43:33 1999
  

  A gzip’d file from 1999. I don’t know why I find this stuff so interesting, but I do. I guess it’s no more and less strange than writing playback systems like this.

• Why can I run this command from the terminal but I get an error when my python runs it from the terminal for me ?

  9 mai 2019, par mu234

  I’m trying to write a python script that basically captures webcam videos from the terminal. When I put the command in a string and use subprocess.call(script, True), I get an error, but when I literally copy/paste the same command to the terminal it works fine.

  This is my python :

  import subprocess
  
  import os
  
  if (os.path.isdir("Videos/Webcam/temp") is False):
  
      dirmake = 'mkdir Videos/Webcam/temp'
  
      subprocess.call(dirmake, True)
  
  cmd = 'ffmpeg -f v4l2 -i /dev/video0 -t 00:00:10 video.webm'
  
  subprocess.call(cmd, True)

  and this is the error

  `FileNotFoundError: [Errno 2] No such file or directory: 'ffmpeg -f v4l2 -i /dev/video0 -t 00:00:10 video.webm': 'ffmpeg -f v4l2 -i /dev/video0 -t 00:00:10 video.webm'`

  If I just run ffmpeg -f v4l2 -i /dev/video0 -t 00:00:10 video.webm from the terminal it works fine.

  Originally the video was supposed to go in Videos/Webcam/temp but I took it out to see if the error had something to do with where I was putting the video. I’m using Ubuntu 18.04.2 LTS if that makes a difference.