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• Working with video in android (crop, overlay, etc.) - how ?

  11 avril 2015, par Mark Korzhov

  There was a task to create an application for Android that lets you record and work with video. There is no problem with recording video from a camera, but I ran into a problem processing videos. For example, you want to crop video, overlay audio, apply a few videos on each other ...

  Are there any libraries that can help me achieve my goals ? I was looking for some information on this issue, some people recommend using ffmpeg. Can ffmpeg library help me achieve what I described above ?

  I would be grateful for any information.

  Thank you.

• Transcoding a Fast Video (think Snapchat, Instagram)

  4 juin 2018, par J DOe

  I am very new to the video world, but have noticed social media services.. particular snapchat and instagram do a great job of getting videos to load fast even on poorer connections. I know some of this is how the videos are transcoded.

  I have gathered some presets I think I should be using when transcoding with ffmpeg, but am not sure of what formats or other parts of it. I would love to hear what people think !

  ffmpeg()
  
      .input(remoteReadStream)
  
      .outputOptions('-preset fast')
  
      .outputOptions('-movflags +faststart')

  Other than that I am not entirely sure what else..

• FFMpeg outputs empty stream/file in C#

  15 juin 2017, par Dark0Matter

  I’m making a bot for discord, and I’m currently trying to use ffmpeg to stream an audio file through voice chat. (Which, many other people succeeded in doing it)

  So basically, I’m using libsodium.dll + opus.dll + ffmpeg.exe to turn an mp3 file into a stream using ffmpeg, and output it.

  This is my "CreateStream" function which starts ffmpeg and turns the mp3 file into a stream/pipe.

      private Process CreateStream(string path)
  
      {
  
          var ffmpeg = new ProcessStartInfo
  
          {
  
              FileName = "ffmpeg.exe",
  
              //Arguments = $"-hide_banner -loglevel panic -i \"{path}\" -ac 2 -f s16le -ar 48000 pipe:1",
  
              Arguments = $"-i {path} -ac 2 -f s16le -ar 48000 pipe:1",
  
              //Arguments = $"-i {path} -ac 2 -f s16le -ar 48000 testingtesting.mp3",
  
              UseShellExecute = false,
  
              RedirectStandardOutput = true,
  
          };
  
          return Process.Start(ffmpeg);
  
      }

  The commented arguments are the other arguments that I’ve tried. (e.g. the last commented arguments line was an attempt to output it to a file instead of a stream, and the file turned out to be empty)

  So basically, my current arguments are

  Arguments = $"-i {path} -ac 2 -f s16le -ar 48000 pipe:1"

  (where pipe:1 is replaceable by any filename such as test.wav)

  and here’s my problem in case you didn’t catch it :

  ffmpeg always outputs empty streams/files.

  Here’s the output that I got in the console.
  https://pastebin.com/zvGgsZZ6

  So my question is,

  Am I using the wrong arguments ?

  And if so, what other arguments can I try to get it fixed ?

  Tl ;dr : ffmpeg outputs empty data to a stream, and it does the same thing when the pipe is replaced by a .wav/.mp3 file.

  EDIT1 : After some time of waiting, I got this : https://pastebin.com/y8rjnsMb

  EDIT2 : I searched for more argument combinations that worked for other people and stumbled upon Arguments = $"-i \"path\" -ab 48000 -f mp3 test.mp3",
  when I tried writing to test.mp3, it worked, but the quality was low.
  Then I tried replacing test.mp3 with pipe:1, but that didn’t work. Help ?