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• How to scape special characters for linux, nodejs exec function

  22 février 2023, par David Chavez

  I'm running this ffmpeg command on my linux server and while I paste it into the terminal, it works just fine but as soon as I use execPromise to run the EXACT same command, it returns an error.

  


  const { exec } = require('child_process');
const { promisify } = require('util');
const execPromise = promisify(exec);

const encode = async ffmpegCode => {
    try {
        console.log(ffmpegCode) //Here I can see that the code is the
                                //exact same one than the one that works
                                //when pasted into the terminal
        await execPromise(ffmpegCode);
        return 200
    } catch (err) {
        console.log(err)
    }
}


  


  I need \: to be interpreted as such. When I type it as is, \:, the error message shows me that it interpreted it as : which is expected.

  


  If I pass in \\:, I expect it to interpret it as I need it which would be \: but the error shows me that it interprets it as \\:.

  


  \\\: is interpreted as \\: and \\\\: is interpreted as \\\\:.

  


  Part of the command passed :

  


  ...drawtext=text='timestamp \\: %{pts \\: localtime \\: 1665679092.241...

  


  Expected command :

  


  ...drawtext=text='timestamp \: %{pts \: localtime \: 1665679092.241...

  


  Error message :

  


  ...drawtext=text='timestamp \\: %{pts \\: localtime \\: 1665679092.241...

  


  How do I get /: through to the exec function ?

  


• Using ffmpeg in Powershell

  27 avril 2016, par Matthew Goode

  Can’t find much information on this, as I believe it’s a pretty noobish problem and there aren’t really any tutorials on it. Can anyone explain how I can use ffmpeg in a powershell script ? I downloaded ffmpeg and I have the path to ffmpeg.exe. Shouldn’t I be able to do something like this ?

  "C:\path\ffmpeg.exe" -i stuff.mp3 stuff.wav

  It returns an error message along the lines of -i not being a recognized parameter. Am I missing something pretty basic here ? Thanks for any help. I’m trying to convert some audio files between .wav, .mp3. and .flac, and if anyone has any better suggestions than ffmpeg then please let me know.

• 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.