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• How would I dynamically link FFmpeg in a C# Project for use with FFMpegCore ?

  15 octobre 2024, par liamliam

  So far, I have FFMpegCore working in my project with a ffmpeg.exe dropped into the project directory. This works, but for LGPL license compliance FFmpeg requires dynamic linking :
  
Use dynamic linking (on windows, this means linking to dlls) for linking with FFmpeg libraries..

  


  While I understand the basic concept of dynamic vs static linking, my problem is likely a misunderstanding of how .dlls work and how they apply to C# and .NET.
  
Would it be possible to compile ffmpeg into a single .dll that could be accessed by FFMpegCore cross-platform ? From what I can gather in the source, FFMpegCore looks for an ffmpeg or ffmpeg.exe file in its configuration path.

  


  Is it possible to have .NET dynamically link FFmpeg and expose it to libraries for use or is that a complete misunderstanding and would I then need a wrapper library with different capabilities ?

  


  I've attempted to find the answer in the relevant documentation, but I found none for this specific use of either library. I suspect my problem might be a fundamental misunderstanding of how these tools work and work together.
My ideal result would be using FFMpegCore with an FFmpeg.dll that works cross-platform instead of the .exe.

  


  Edit 1 : @taratect's answer and graphic sent me down a path that cleared up quite a bit about exes and dlls. .Net compiles source code down to platform agnostic Intermediate Language in the form of a .dll or .exe(completely different to C++ variants of these files), which is executed by the Common Language Runtime using a Just In Time compiler to convert that Intermediate Language to Machine Code that can be run on the specific platform .Net is installed on. C++(FFmpeg) compiles directly to platform specific Machine Code (as shown in the graphic), confusingly in the form of a .dll or .exe (on Windows). .Net can indeed load and run machine code unmanaged by Common Language Runtime, since everything is run as Machine Code by the end, however memory and other complexities must then be managed by me, which seems to be what FFMpegCore does in wrapping the executable. I might still be confused/incorrect on some of this, unmanaged code is beyond my understanding so far.
This does more or less confirm that FFMpegCore probably can't be expected to use FFmpeg in the way I hoped and a better workaround might be having the user just supply an FFmpeg source or implement a downloader as part of installation so that I don't have to redistribute it at all.

  


• ffmpeg multiple pipes with different filters and outputs

  3 janvier 2024, par diegoddox

  I'm trying to pipe multiple outputs to an s3 but so far it's only working if I tried with only one pipe as soon as I add more I get Could not write header (incorrect codec parameters ?): Broken pipe error.

  


  aws s3 cp s3://bucket-name/original.mp4 - | \
  ffmpeg -f mp4 -i pipe:0 \
  -vf "scale=1280x720:flags=lanczos" -c:a aac -b:a 96k -movflags frag_keyframe+empty_moov -f mp4 pipe:1 | aws s3 cp - s3://bucket-name/720.mp4 --region my-region \
  -vf "scale=854x480:flags=lanczos" -c:a aac -b:a 96k -movflags frag_keyframe+empty_moov -f mp4 pipe:2 | aws s3 cp - s3://bucket-name/480.mp4 --region my-region \
  -vf "scale=640x360:flags=lanczos" -c:a aac -b:a 96k -movflags frag_keyframe+empty_moov -f mp4 pipe:3 | aws s3 cp - s3://bucket-name/360.mp4 --region my-region \
  -ss 00:00:00 -t 3 -vf "fps=10,scale=720:-1" -movflags frag_keyframe+empty_moov -f gif pipe:4 | aws s3 cp - s3://bucket-name/thumbnail.gif --region my-region


  


  Thanks in advance

  


• How to convert animated webp to gif in android / java ?

  21 avril 2022, par UHS

  I want to convert the animated webp files to gif file and looking for solution since couple of days but did not get any easy straight solution yet.

  


  I tried ffmpeg but it could not do the job and after looking for solution I found that webp decoder is not implemented in ffmpeg yet.
https://trac.ffmpeg.org/ticket/4907

  


  I also checked libwebp library by google and they also says animated webp is not supported. https://developers.google.com/speed/webp/docs/dwebp

  


  I tried demo of aspose this library also fail to convert animated webp to gif.
https://products.aspose.com/imaging/java/conversion/webp-to-gif/

  


  I think ImageMagick can convert animated webp to gif but do not know how to implement that in my project.
How can I avoid dropouts when using (imagemagick) `mogrify` to convert webp files to animated gif ?

  


  So is there any easy way to convert webp to gif