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• Using FFmpeg in .net ?

  15 juillet 2016, par daniel

  So I know its a fairly big challenge but I want to write a basic movie player/converter in c# using the FFmpeg library. However, the first obstacle I need to overcome is wrapping the FFmpeg library in c#. I’ve downloaded ffmpeg but couldn’t compile it on Windows, so I downloaded a precompiled version for me. Ok awesome. Then I started looking for C# wrappers.

  I have looked around and have found a few wrappers such as SharpFFmpeg (http://sourceforge.net/projects/sharpffmpeg/) and ffmpeg-sharp (http://code.google.com/p/ffmpeg-sharp/). First of all, I wanted to use ffmpeg-sharp as its LGPL and SharpFFmpeg is GPL. However, it had quite a few compile errors. Turns out it was written for the mono compiler, I tried compiling it with mono but couldn’t figure out how. I then started to manually fix the compiler errors myself, but came across a few scary ones and thought I’d better leave those alone. So I gave up on ffmpeg-sharp.

  Then I looked at SharpFFmpeg and it looks like what I want, all the functions P/Invoked for me. However its GPL ? Both the AVCodec.cs and AVFormat.cs files look like ports of avcodec.c and avformat.c which I reckon I could port myself ? Then not have to worry about licencing.

  But I want to get this right before I go ahead and start coding. Should I :

  1. Write my own C++ library for interacting with ffmpeg, then have my C# program talk to the C++ library in order to play/convert videos etc.

  OR

  2. Port avcodec.h and avformat.h (is that all i need ?) to c# by using a whole lot of DllImports and write it entirely in C# ?

  First of all consider that I’m not great at C++ as I rarely use it but I know enough to get around. The reason I’m thinking #1 might be the better option is that most FFmpeg tutorials are in C++ and I’d also have more control over memory management than if I was to do it in c#.

  What do you think ?
  Also would you happen to have any useful links (perhaps a tutorial) for using FFmpeg ?

• python modules ffmpeg and ffprobe are installed but youtube-dl not able to find

  12 avril 2022, par Akshay Hiremath

  I'm using python 3.8 on MacOS Big Sur

  


  I installed python module package for youtube-dl with

  


  pip3 install -upgrade youtube-dl


  


  I wanted to do post processing on the content downloaded so I installed python packages ffprobe and ffmpeg.

  


  pip3 install ffprobe
Collecting ffprobe
  Downloading https://files.pythonhosted.org/packages/95/9c/adf90d21108d41f611aa921defd2f2e56d3f92724e4b5aa41fae7a9972aa/ffprobe-0.5.zip
Installing collected packages: ffprobe
  Running setup.py install for ffprobe ... done
Successfully installed ffprobe-0.5

pip3 install ffmpeg
Collecting ffmpeg
  Downloading https://files.pythonhosted.org/packages/f0/cc/3b7408b8ecf7c1d20ad480c3eaed7619857bf1054b690226e906fdf14258/ffmpeg-1.4.tar.gz
Installing collected packages: ffmpeg
  Running setup.py install for ffmpeg ... done
Successfully installed ffmpeg-1.4


  


  pip3 list 
Package    Version   
---------- ----------
ffmpeg     1.4       
ffprobe    0.5           
youtube-dl 2021.12.17 


  


  Still it is complaining can't find ffprobe and ffmpeg :

  


  youtube_dl.utils.DownloadError: ERROR: ffprobe/avprobe and ffmpeg/avconv not found. Please install one.


  


  I see both packages in /Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/

  


  Trying to figure out what am I doing wrong. Many other answers to similar questions on SFO are suggesting installing these packages in the OS using brew etc. but in my case "I want to do everything through python". So shouldn't just installing python modules be enough ?

  


• FFMPEG : Encoding WEBM with fast-seek and copyts leads to wrong video length

  13 mars 2020, par TheOverlord2D

  I’m trying to convert a scene from a soft-subbed MKV file into a hard-subbed WEBM file with two-pass. The video encodes fine, but the file shows the wrong length when opened on a media player (it’s showing as if I had encoded the original file from the starting point all the way to the end).

  This is the command I’m using :

  set timestamp=-ss 12:59.069 -to 16:14.277
  
  
  
  ffmpeg -y %timestamp% -copyts -i source.mkv -shortest -c:v libvpx-vp9 -pass 1 -b:v 0 -crf 33 -threads 8 -speed 4 -tile-columns 6 -frame-parallel 1 -an -sn -vf scale=-1:720,subtitles=source.mkv -f webm NUL
  
  ffmpeg -y %timestamp% -copyts -i source.mkv -shortest -c:v libvpx-vp9 -pass 2 -b:v 0 -crf 33 -threads 8 -speed 2 -tile-columns 6 -frame-parallel 1 -auto-alt-ref 1 -lag-in-frames 25 -c:a libopus -b:a 64k -sn -vf scale=-1:720,subtitles=source.mkv -f webm out.webm

  When opening the video in MPC-BE, the video plays regularly until around the point shown on https://i.stack.imgur.com/6bRwc.png (which is where the scene I wanted to cut out ends) then it just skips to the end of the file, and this wrong length is giving me all sorts of issues when I try to use the encoded video.