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• Run ffmpeg audio under Windows with Flutter

  11 janvier, par Chris

  I'd like to stream audio comming from my microphone in my flutter app in the windows desktop version.

  


  Since there is no library that seems to do such thing while supporting windows desktop app, I have tried using Process like this :

  


  // Start the FFmpeg process to capture audio
ffmpegProcess = await Process.start(
  'ffmpeg',
  [
    '-f', 'dshow', // Specify DirectShow input for Windows
    '-i', 'audio="$selectedMic"', // Input audio device (selected mic)
    '-f', 'wav', // Set audio format
    '-ar', '44100', // Set audio sample rate
    '-ac', '1', // Mono channel
    '-b:a', '128k', // Set audio bitrate
    'pipe:1', // Output to stdout
  ],
);

// Listen for data on stdout (audio stream)
ffmpegProcess.stdout.listen((data) async {
  // Send audio data to the server as it comes in
  await sendAudioToServer(data);
});


  


  I've tested the command directly in my terminal (not in the flutter app) and it works fine.

  


  When I run this code in my Flutter app, my task manager also shows a "ffmpeg" process, but somehow there is no stream output in flutter, even after ensuring that the selectedMic variable is correct or even when its hardcoded.

  


  Since this command runs without issue in my terminal and even in python, I am wondering why it does not work in Flutter.

  


  Starting my vscode as administrator also don't solve the issue (I wanted to check if it's a permission issue).

  


  Also relevant : When I run the "ffmpeg -version" command, I get an output for the version, meaning that this is not an installation problem (ffmpeg bin folder is in my PATH environment variable). The problem seems to come from recording from the microphone in flutter, but I don't get why.

  


  ffmpegProcess = await Process.start('ffmpeg', ['-version']);  // this works


  


  I'd love to get some suggestions where the problem could come from or any kind of alternative solutions.

  


• How to create a Master Playlist for HLS using a Java wrapper library for FFMPEG

  17 janvier 2019, par Abhishek Nandgaonkar

  I am trying to find/use a Java Library that wraps around FFMPEG to create HLS compatible segments and metadata files along with a master metadata file.

  Most existing libraries perform encoding just fine and allow extra functions for additional audio/video parameters. But I could not find a good way for using them to create a master metadata file and other resolution/bandwidth/bitrate based metadata + segments.

  One way that I am planning to go about it is running the piece of code that performs HLS for me multiple times to suit the different bitrates and then programmatically look at the metadata files to compose the master metadata file. But that adds room for errors.

  If you know of an existing library that can do it for me. Please share the details. It would really help out.

  Libraries :

  • https://github.com/bramp/ffmpeg-cli-wrapper
  • https://github.com/hoary/JavaAV
  • https://github.com/kokorin/Jaffree
  • http://www.xuggle.com/

  Documentation (see Section Master Playlist)
  https://developer.apple.com/library/content/referencelibrary/GettingStarted/AboutHTTPLiveStreaming/about/about.html

  FFMPEG command line code that works for me

  ffmpeg -loglevel debug -threads 4 -vsync 1 -i 'id.mp4' -vf yadif -g 29.97 -r 29.97 -b:v:0 5250k -c:v libx264 -rc:v vbr_hq -pix_fmt yuv420p -profile:v main -level 4.1 -rc-lookahead 32 -forced-idr 1 -b:v:1 4200k -c:v libx264 -rc:v vbr_hq -pix_fmt yuv420p -profile:v main -level 4.1 -rc-lookahead 32 -forced-idr 1 -b:v:1 3150k -c:v libx264 -rc:v vbr_hq -pix_fmt yuv420p -profile:v main -level 4.1 -rc-lookahead 32 -forced-idr 1 -b:a:0 256k -b:a:0 192k -b:a:0 128k -c:a aac -ar 48000  -map 0:v -map 0:a:0 -map 0:v -map 0:a:0 -map 0:v -map 0:a:0 -f hls -var_stream_map "v:0,a:0  v:1,a:1 v:2,a:2" -master_pl_name  master.m3u8 -t 300 -hls_time 10 -hls_init_time 4 -hls_list_size 0 -master_pl_publish_rate 10 -hls_flags delete_segments+discont_start+split_by_time "vs%v_manifest.m3u8"

  Any help would be appreciated. Thanks in advance.

• Mingw-w64 builded FFmpeg doesn't show any usage information

  26 octobre 2013, par user1240328

  First I wanted to modificate ffplay according to my requirments. Then I noticed that original ffplay from my build can't play some video files, but it didn't write any message to console. Then I noticed that ffmpeg also don't write any usage message when I run it without params. But it works. If I run it from terminal it's like running asynchronously ! The terminal just shows next row. I mean it asks for a next command. But the ffmpeg process is visible in task manager and it writes the output video file what I had requested !

  I created following souce file. I have modified the Makefile. So it have built the exe-file works just the same way. I have no idea how it can be.

  #include 
  
  #include "cmdutils.h"
  
  
  
  const char program_name[] = "hello";
  
  const int program_birth_year = 2013;
  
  
  
  void show_help_default(const char *opt, const char *arg)
  
  {
  
      printf("zxcvbnm\n");
  
  }
  
  
  
  int main(int argc, char **argv)
  
  {
  
      printf("1234567890\n");
  
      return 0;
  
  }

  I want to prevent this behavior.

  I want to make printf working in traditional manner.

  How I build FFmpeg :

  PKG_CONFIG_PATH=/home/developer/workspace/MinGW32fs/lib/pkgconfig/ \
  
  SDL_CONFIG=/home/developer/workspace/MinGW32fs/bin/sdl-config \
  
  ./configure \
  
    --prefix=/home/developer/workspace/MinGW32fs \
  
    --extra-ldflags="-L/home/developer/workspace/MinGW32fs/lib" \
  
    --extra-cflags="-I/home/developer/workspace/MinGW32fs/include" \
  
    --arch=x86 --target-os=mingw32 --cross-prefix=i686-w64-mingw32-  \
  
    --pkg-config=pkg-config   --enable-libtheora --enable-libvorbis --enable-libvpx \
  
    --enable-outdev=sdl --enable-shared --disable-static \
  
    --disable-doc --disable-manpages --disable-podpages
  
  
  
  make