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• A ffmpeg command method into a webjob

  2 juillet 2017, par Fearhunter

  I am new with Azure Webjobs. I made an ffmpeg function to slice a stream into separate mp4 files :

  public Process SliceStream()
  
  {
  
      var url = model_s.Url;
  
      var cuttime = model_s.Cuttime;
  
      var output = model_s.OutputPath;
  
      return Process.Start(new ProcessStartInfo
  
      {
  
          FileName = "ffmpeg.exe",
  
          Arguments = $"-i \"{url}\" -c copy -flags +global_header -f segment -segment_time \"{cuttime}\" -segment_format_options movflags=+faststart -reset_timestamps 1 \"{output}\"",
  
          UseShellExecute = false,
  
          RedirectStandardOutput = true
  
      });
  
  }

  The var properties are the variables for the user input on the front-end. I want to scheduled this method into a webjob. How can I achieve this ? I saw an article on google

  https://zimmergren.net/getting-started-with-building-azure-webjobs-timer-jobs-for-your-office-365-sites/

  Need I just follow these steps to achieve my goal ? Or must I add some C# code to achieve this ?

• Store image specific metadata in video

  5 mai 2021, par VocoJax

  I'd like to store XMP data in my PNG images and then compress my images using a lossless compression codec in a video for long-term storage.

  


  Is this possible ? Is per-image metadata discarded when compressing into a video ?

  


  For context, I need a pythonic solution utilizing FFMPEG to do the video compression. I'm aware that OPENCV discards VIDEO metadata. Further, I care not for VIDEO metadata, only per image metadata. Additionally, the type of metadata I'm storing is in reference to the timestamp of the frame, the camera it was taken on, and maybe even some information regarding on-prem AI detecting like bounding box of an object in frame or something like that.

  


  My current approach is just to use OPENCV to get the frames and then record the time into a fat array. Once my video file gets to a specific size or frame count, I'll just prepend the json array of timestamps to the video file along with a 32-bit integer regarding how long the array is. This solution will definitely work, but, it's a hassle to record the timestamps in memory, plus write custom scripts to load my video again (parsing the timestamps off the front of it beforehand).

  


  Who's got the magic solution ? Could I use the approach I'm currently using except attach the frame timestamps to the VIDEO metadata instead ?

  


• python with ffmpeg fails randomly

  8 juillet 2017, par Jim Weisbin

  Python 2.7.1 on Mac OS X 10.12.5, ffmpeg 3.3.2 (installed with Brew).

  I’m calling ffmpeg on a loop though thousands of Apple Lossless files, converting to mp3 and tagging as I go. Here’s the call :

  thecall = '/usr/local/bin/ffmpeg -hide_banner -loglevel error -i ' + <path to="to" m4a="m4a" file="file"> + ' -i ' + <path to="to" artwork="artwork"> + ' -map 0:0 -map 1:0 -id3v2_version 3 -map_metadata -1 -metadata album="xxx" -metadata artist="xxx" -metadata comment="Cover (Front)" -f mp3 -b:a 128K ' + <path to="to" mp3file="mp3file">'
  
  
  
  os.system(thecall)
  
  </path></path></path>

  this works perfectly from the command line, and also works from Python most of the time, but randomly fails with the message

  [alac @ 0x7fc888858800] invalid samples per frame: 0
  
  Error while decoding stream #0:0: Invalid data found when processing input

  What’s strange is that on the files it failed on, if I run it from the command line it succeeds. I tried putting in time.sleep(5) but no change. And the failures are not always on the same file, so it seems like it’s a memory or threading issue. I also tried calling with subprocess() instead, no change.

  Any help would be appreciated.