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• constructing an ffmpeg script for use in Xcode/swift project

  21 octobre 2019, par NCrusher

  I’m going back to the drawing board with this post because I’ve been through so much trial and error over the last day with this issue that the information I posted earlier is no longer relevant.

  I’ve only been learning both Swift and FFmpeg for a few weeks, and I’ve just exhausted my ability to troubleshoot this.

  I’m maybe 90% certain this is a problem with my ffmpeg script, rather than with the Swift component. But I think it’s complicated by what characters need special formatting in Swift (particularly mathematical operatives.)

  I started off using a method in Xcode modeled after this post, which Xcode actually managed to guide me through updating for current versions of swift without breaking. Which left me with this :

  func ffmpegConvert(inputPath: String, filters: String, outputPath: String) {
  
      guard let launchPath = Bundle.main.path(forResource: "ffmpeg", ofType: "") else { return }
  
      do {
  
          let convertTask: Process = Process()
  
          convertTask.launchPath = launchPath
  
          convertTask.arguments = [
  
              "-i", inputPath,
  
              filters,
  
              outputPath
  
          ]
  
          convertTask.standardInput = FileHandle.nullDevice
  
          convertTask.launch()
  
          convertTask.waitUntilExit()
  
      }
  
  }

  I call this function when I click the "Start Conversion" button on my app. Like I said, that part seems to work fine. The problem is either in the way ffmpeg is being called by the app, or with the construction of the strings in my arguments array.

  The inputFilePath and outputFilePath strings are self-explanatory. Both of them are perfectly acceptably formatted filepath strings.

  The filters is a little tougher. My app has five conversion options and a different filter set for each one. One is as simple as -c copy and the most complex is -c:a libmp3lame -ac 1 -ar 22050 -q:a 9 (I’m working with audiobooks so I don’t need a lot of complexity in my arguments.

  The app appears to be launching ffmpeg perfectly. But the console keeps giving me errors. And the errors keep changing depending on what I try. Here’s what I’ve been through so far :

  var inputFilePath = "/Volumes/CSW External/ffmpeg/diamonds.aac"
  
  var ffmpegFilters = "-c copy"
  
  var outputFilePath = "/Volumes/CSW External/ffmpeg/diamonds.m4b"

  Result :

  Unrecognized option ’c copy’.
  Error splitting the argument list : Option not found

  Next attempt, I tried var ffmpegFilters = "--c copy". Result was the same error.

  Then I tried var ffmpegFilters = " -c copy" and it actually read the metadata from my file before throwing a different error at me :

  Unable to find a suitable output format for ’ -c copy’ -c copy :
  Invalid argument

  I’m assuming that the fact that it read the metadata before throwing a different error at me means I made...some form of progress ?

  I spent a few hours researching that particular error and why people might be getting it and couldn’t find a situation that was analogous to what I was trying to do. Mostly people were encountering it from the command line and/or other operating systems. So no help there.

  At that point, since I was just throwing things at the wall to see what might stick, I decided to throw the whole command, inputPath / ffMpegFilters / outputPath into a single string to see if I could make that work (under the logic that if it did, I could narrow the cause of my trouble down to the way the separate strings are being constructed by XCode.)

  I tried it both with the whitespace in the filepath and with the whitespace escaped out (using double \ as required by Swift.) The ffmpeg log came displayed a perfectly valid

  Doing so took me back to the first error I got :

  Unrecognized option ’-c copy’.
  Error splitting the argument list : Option not found

  So then I started researching THAT error. Some of the discussions I came across indicated that the problem was that the arguments couldn’t all be in a single string, they needed to be split up and put in an array. Which I could see for a longer argument, but -c copy shouldn’t need that.

  But I decided to give it a go. Formerly my method for constructing the string of arguments would have looked like this

  func conversionSelection() {
  
      if inputFileUrl != nil {
  
          let conversionChoice = conversionOptionsPopup.indexOfSelectedItem
  
          switch conversionChoice {
  
              case 1 :
  
                  outputExtension = ".mp3"
  
                  ffmpegFilters = "-c:a libmp3lame -ac 1 -ar 22050 -q:a 9"
  
              (...case 2, 3, 4, default, etc)
  
          }
  
      }
  
  }

  Now it looks more like this :

  func conversionSelection() {
  
      if inputFileUrl != nil {
  
          let conversionChoice = conversionOptionsPopup.indexOfSelectedItem
  
          switch conversionChoice {
  
              case 1 :
  
                  outputExtension = ".mp3"
  
                  ffmpegCodec = "-c:a libmp3lame"
  
                  ffmpegChannels = "-ac 1"
  
                  ffmpegSampling = "-ar 22050"
  
                  ffmpegBitrate = "-q:a 9"
  
              (case 2, case 3, case 4, default, etc)
  
          }
  
      }
  
  }

  Unfortunately, this just brought me full circle. If I try to use -c:a libmp3lame or --c:a libmp3lame I get the Error splitting the argument list: Option not found error. Interestingly, however, it gives the argument with relation to the ffmpegSampling argument, which is a slight difference.

  If I put a whitespace in front of it -c:a libmp3lame it will get far enough into the process to read the input file metadata, then I get this :

  Unable to find a suitable output format for ’ -c:a libmp3lame’ -c:a
  libmp3lame : Invalid argument

  I’m stumped. I thought this was going to be an easy fix, but I’ve been at it almost a full day with all the trial and error, and nothing is working, and I’ve exhausted my newbie understanding of both Swift and ffmpeg.

• I'm building a rust project，but it keep saying "could not find native static library 'avfornat' perhaps an —L flag is missing ?"

  8 juillet 2023, par Carrot

  I already installed the FFmpeg and ask ChatGPT for many times,but whatever I do,It just keep goes wrongerror

  


  ffmpeg

  


  I already changed my work environment form windows to ubuntu and try to add the path of libavformat.a in every cargo.toml files

  


• Libavcodec "the procedure entry point for av_frame_alloc could not be located" error in Visual Studio 2017 C++ project

  25 novembre 2019, par Aves

  I am trying to use libavcodec from ffmpeg library in C++ with Visual Studio 2017 Community. I downloaded the latest x64 dev and shared builds from zeranoe (version 20171217), set up include directories and additional libraries in Visual Studio for x64 build, added DLL files from shared package to my PATH.

  This is my sample test code :

  extern "C" {
  
  #include 
  
  }
  
  int main() {
  
      avcodec_register_all();
  
      AVFrame *pAvFrame = av_frame_alloc();
  
      av_frame_free(&pAvFrame);
  
      return 0;
  
  }

  The code compiles without problems but when I run the application I see a dialogue window with error message "the procedure entry point for av_frame_alloc could not be located in DLL" (actual message is not in English, this is the translated version).

  I tried to set Linker->Optimization->References to /OPT:NOREF as it was advised in the similar questions but it did not help.

  Dependency walker shows that av_frame_alloc is exported, "Entry Point" is not bound. A little bit strange is that av_frame_alloc is displayed in both avcodec-58.dll (as red) and avutil-56.dll (as green). Maybe the reason is that the application is trying to get this function from avcodec instead of avutil, but I’m not sure, since I did not check the source code of these libraries.

  So the question is how to set up such a simple FFMPEG-based C++ project in VS2017, where I’m wrong ?

  UPD. 1.

  Linker flags : /OUT :"C :\work\code\TestFfmpeg\x64\Release\TestFfmpeg.exe" /MANIFEST /NXCOMPAT /PDB :"C :\work\code\TestFfmpeg\x64\Release\TestFfmpeg.pdb" /DYNAMICBASE "c :\work\dev\ffmpeg-20171217-387ee1d-win64-dev\lib*.lib" "kernel32.lib" "user32.lib" "gdi32.lib" "winspool.lib" "comdlg32.lib" "advapi32.lib" "shell32.lib" "ole32.lib" "oleaut32.lib" "uuid.lib" "odbc32.lib" "odbccp32.lib" /DEBUG:FULL /MACHINE:X64 /OPT:NOREF /PGD :"C :\work\code\TestFfmpeg\x64\Release\TestFfmpeg.pgd" /MANIFESTUAC :"level=’asInvoker’ uiAccess=’false’" /ManifestFile :"x64\Release\TestFfmpeg.exe.intermediate.manifest" /OPT:ICF /ERRORREPORT:PROMPT /NOLOGO /TLBID:1