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• Video editing in UWP apps

  23 septembre 2021, par MatS2510

  I'm creating an video downloading app in C# and Universal Windows Platform. App downloads movies in three different file sets depending on the source :

  


  

  • .ts audio & video file

  


  • .mp4 only video file and .webm only audio file

  


  • .mp4 audio & video file
The video lenghts, on which I tested the app, range from a few seconds to several hours. Video qualities are standard YouTube qualities.

  


  


  The next step is video editing. User can specify start and end trimming timestamp. Video can be saved in three different modes :

  


  

  • Audio & Video

  


  • Only audio

  


  • Only video

  


  


  This is where the problem begins.

  


  I can't use FFmpeg as executable, because UWP framework doesn't allow to run external app.

  


  So I tried to use Windows.Media.Editing library. It works fine with all .mp4 audio & video files and some .ts files (but only with short videos up to an hour). Other cases throws two types of exceptions :

  


  

  • System.Exception
HResult=0xC00DA7FC
Message=Stream is not in a state to handle the request. Stream is not in a state to handle the request.
Source=System.Private.CoreLib

  


  • System.Exception
HResult=0xC00D6D60
Message=A valid type has not been set for this stream or a stream that it depends on. (Exception from HRESULT : 0xC00D6D60)
Source=System.Private.CoreLib

  


  


  I wrote a separate question about it : Exception when rendering a video in UWP . Here is also a link to an example (In comments with sample videos, which causes an error. Link to github repository.) that downloads and tries to convert the .ts file to the .mp4 file.

  


  So I decided to try the most complicated solution. I created a C++ DLL project and set build output destination to the new folder in the main app project folder (and set this folder to copy to build output directory). I installed an ffmpeg libraries by vcpkg and imported them in C++ project.
Here is the .cpp file :

  


  #include "pch.h"
#include "mux.h"

extern "C" {
    #include "libavformat/avformat.h"
}

int test() {
    av_register_all();
    return 0;
}


  


  Here is the header :

  


  #pragma once

#ifdef FFMPEGLIB_EXPORTS
#define FFMPEGLIB_API __declspec(dllexport)
#else
#define FFMPEGLIB_API __declspec(dllimport)
#endif

extern "C" FFMPEGLIB_API int test();


  


  And here is the C# class where is imported C++ function :

  


  class FFmpeg
{
    [DllImport(@"FFmpeg\FFmpegLib.dll")] private static extern int test();

    public static void Test()
    {
        test();
    }
}


  


  But calling an Test() void throws an error :
System.DllNotFoundException : 'Unable to load DLL 'FFmpeg\FFmpegLib.dll' or one of its dependencies : The specified module could not be found. (Exception from HRESULT : 0x8007007E)'

  


  There are also ffmpeg libraries (avcodec-58.dll, avformat-58.dll, avutil-56.dll, swresample-3.dll) in FFmpeg folder.
I also tried to import avformat-58.dll directly in C# (main app project) and call av_register_all() function, but it throws the same exception. I also checked if I could include "libavformat/avformat.h" in C++ UWP app, but it shows error "cannot open source file "libavformat/avformat.h"". I guess that C libraries are incompatible with UWP, but I'm not sure.

  


  I have no more ideas. If it is not possible to use the methods I have mentioned, my question is Are there any other ways to process videos in UWP app ?

  


• ffmpeg convert images to mp4 error

  31 mai 2013, par Ryan Saxe

  So I have a script that grabs a bunch of images from the web and then converts them into a movie. Yet I get a whole bunch of errors when I run it.

  First let me show what I am running and then I will post the error because it's huge :

  #for gif
  
  #call('convert -set delay 5 -loop 0 ' + folder + '*.jpg ' + name + '.gif', shell=True)
  
  #for mov
  
  #call('convert -quality 100 ' + folder + '*.jpg ' + name + '.mov', shell=True)
  
  #for organized movie
  
  call('ffmpeg -r 10 -b 1800 -i ' + folder + '%0' + str(size) + 'd.jpg ' + name + '.mp4', shell=True)

  So the commented out versions work fine, but I need to use the 3rd version ! Here is the response I get from ffmpeg :

  ffmpeg version 1.2 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Mar 31 2013 21:55:33 with Apple clang version 4.1 (tags/Apple/clang-421.11.66) (based on LLVM 3.1svn)
  
    configuration: --prefix=/opt/local --enable-swscale --enable-avfilter --enable-libmp3lame --enable-libvorbis --enable-libopus --enable-libtheora --enable-libschroedinger --enable-libopenjpeg --enable-libmodplug --enable-libvpx --enable-libspeex --enable-libfreetype --mandir=/opt/local/share/man --enable-shared --enable-pthreads --cc=/usr/bin/clang --arch=x86_64 --enable-yasm --enable-gpl --enable-postproc --enable-libx264 --enable-libxvid
  
    libavutil      52. 18.100 / 52. 18.100
  
    libavcodec     54. 92.100 / 54. 92.100
  
    libavformat    54. 63.104 / 54. 63.104
  
    libavdevice    54.  3.103 / 54.  3.103
  
    libavfilter     3. 42.103 /  3. 42.103
  
    libswscale      2.  2.100 /  2.  2.100
  
    libswresample   0. 17.102 /  0. 17.102
  
    libpostproc    52.  2.100 / 52.  2.100
  
  Please use -b:a or -b:v, -b is ambiguous
  
  [mjpeg @ 0x7f8cc402a800] [IMGUTILS @ 0x7fff5a680ae0] Picture size 10835x53928 is invalid
  
      Last message repeated 26 times
  
  [mjpeg @ 0x7f8cc402a800] Found EOI before any SOF, ignoring
  
  [mjpeg @ 0x7f8cc402a800] mjpeg: unsupported coding type (cf)
  
  [mjpeg @ 0x7f8cc402a800] mjpeg: unsupported coding type (c8)
  
  [mjpeg @ 0x7f8cc402a800] [IMGUTILS @ 0x7fff5a680ae0] Picture size 54310x53928 is invalid
  
  [mjpeg @ 0x7f8cc402a800] only 8 bits/component accepted
  
      Last message repeated 8 times
  
  [mjpeg @ 0x7f8cc402a800] mjpeg: unsupported coding type (c5)
  
  [mjpeg @ 0x7f8cc402a800] [IMGUTILS @ 0x7fff5a680ae0] Picture size 10835x53928 is invalid
  
      Last message repeated 12 times
  
  [mjpeg @ 0x7f8cc402a800] mjpeg: unsupported coding type (cf)
  
  [mjpeg @ 0x7f8cc402a800] only 8 bits/component accepted
  
  [mjpeg @ 0x7f8cc402a800] mjpeg: unsupported coding type (cf)
  
  [mjpeg @ 0x7f8cc402a800] only 8 bits/component accepted
  
  [mjpeg @ 0x7f8cc402a800] mjpeg: unsupported coding type (cf)
  
  [mjpeg @ 0x7f8cc402a800] only 8 bits/component accepted
  
  [image2 @ 0x7f8cc4029c00] decoding for stream 0 failed
  
  [image2 @ 0x7f8cc4029c00] Could not find codec parameters for stream 0 (Video: mjpeg): unspecified size
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  /Users/ryansaxe/Desktop/kaggle_parkinsons/MOVIES/%03d.jpg: could not find codec parameters

  Note :

  [mjpeg @ 0x7f8cc402a800] mjpeg: unsupported coding type (cf)
[mjpeg @ 0x7f8cc402a800] only 8 bits/component accepted

  repeated about 30 times, but i cut it out of the traceback because it was overwhelming.

  Question : What did I do wrong and how do I fix it ?

  Edit :

  I download the jpeg files using the urllib python library's urlretrieve. This is how I save them :

  for src,name in zip(urls,range(len(urls))):
  
      file_name = folder + str(name) + '.jpg'
  
      urlretrieve(src, file_name)

• Flutter ffmpeg : Video merger not working

  17 septembre 2021, par Madhusri J

  I have been trying to merge two videofiles using ffmpeg in flutter but a single videofile is merging two times and the sound of video is not working

  


  This is my code

  


   final appDir = await getExternalStorageDirectory();
 String rawDocumentPath = appDir!.path;
 final outputPath = '$rawDocumentPath/videomerge.mp4';

 final FlutterFFmpeg _flutterFFmpeg = new FlutterFFmpeg();

 String commandToExecute = '-y -i ${VideoFiles[0].path} -i ${VideoFiles[1].path} 
  -filter_complex \'[0:v][0:v]concat=n=2:v=1:a=0[out]\' -map \'[out]\' $outputPath';

 _flutterFFmpeg.execute(commandToExecute).then((rc) => print("FFmpeg process exited with 
 rc $rc"));


  


  Any help would be greatly appreciated :)