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• How do I use find and ffmpeg to batch convert a bunch of .flac files to .mp3 ?

  30 avril 2019, par Keith

  I have a directory with a bunch of .flac files that I need to convert to .mp3. I plan to use ffmpeg from the command line to do the conversions and I’d like to avoid doing this manually for every file. I’m familiar with the find command but I’m having difficulty using it with ffmpeg which requires both input and output filenames. I imagine using something like

  find . -name "*.flac" -exec ffmpeg -i {}.flac {}.mp3 +

  But of course this doesn’t work. For one thing it fails to strip prefixes and suffixes from the filename being passed to ffmpeg.

  Please also note that the filenames include whitespace so the solution has to ignore whitespace successfully. I’m also on OS X having built ffmpeg with homebrew.

• How to make video loop properly ?

  28 mai 2019, par woopwoop399

  I want to play this video in a loop https://www.nicovideo.jp/watch/sm16617386 . I want to play an mp4 file in such a way, that whenever it gets to some point in the video (let’s say, 30.3 seconds), it will loop back (to for example 5.85 seconds).

  I tried to add this code in ffplay.c , it didn’t work well enough, I can hear the transition. I guess seeking isn’t fast enough, or audio needs to be looped in an independant way somehow.

  static void video_refresh(void *opaque, double *remaining_time)
  
  {
  
     (original code here...)
  
      time = get_master_clock(is);
  
      if (isnan(time))
  
          time = (double)is->seek_pos / AV_TIME_BASE;
  
      if (time > jump_when) {
  
          stream_seek(is, (int64_t)(6.0 * AV_TIME_BASE), (int64_t)(0.0 * AV_TIME_BASE), 0);
  
      }
  
  }

  My current plan is to just dig into ffmpeg, understand how video and audio decoders work, and savestate/loadstate the decoders.

• Python OpenCV real-time blurring with saving to output

  10 janvier 2024, par Oleg Novosad

  I have a live video stream via RTSP from my IP camera. I want to blur faces on that stream and output for mobile usage (HLS, H.264, etc). All this should ideally happen in real-time — with the minimum of resources consumed. I plan to deploy this later to some cloud, so the less money I spend on resources the better.

  


  Currently I have a working solution like so :

  


  

  • I capture video using OpenCV

  


  • I update every frame with Gaussian Blur and save it to some folder

  


  • After some amount of frames I create MP4 / AVI / whatever video and make it accessible via HTTP URL

  


  • All of it is running on Django for now

  


  


  I know I am doing something wrong, can someone suggest a better solution ?