// Note: CreateFFmpegParam is optional and and corePath is also optional
FFmpeg ffmpeg = createFFmpeg(CreateFFmpegParam(log: true, corePath: 'https://unpkg.com/@ffmpeg/core@0.11.0/dist/ffmpeg-core.js'));

// suppose ffmpeg-core lives under https://myserver.com/ffmpeg/ffmpeg-core.js
final url = Uri.base.resolve('ffmpeg/ffmpeg-core.js').toString();
FFmpeg ffmpeg = createFFmpeg(CreateFFmpegParam(corePath: url));

Future<Uint8List> exportVideo(Uint8List input) async {
  // Note you can always reuse the same ffmpeg instance
  FFmpeg? ffmpeg;
  try {
    ffmpeg = createFFmpeg(CreateFFmpegParam(log: true));
    ffmpeg.setLogger(_onLogHandler);
    ffmpeg.setProgress(_onProgressHandler);

    // Check ffmpeg.isLoaded() before ffmpeg.load() if you are reusing the same instance
    if (!ffmpeg.isLoaded()) {
      await ffmpeg.load();
    }

    const inputFile = 'input.mp4';
    const outputFile = 'output.mp4';

    ffmpeg.writeFile(inputFile, input);

    // Equals to: await ffmpeg.run(['-i', inputFile, '-s', '1920x1080', outputFile]);
    await ffmpeg.runCommand('-i $inputFile -s 1920x1080 $outputFile');

    final data = ffmpeg.readFile(outputFile);
    return data;
  } finally {
    // Do not call exit if you want to reuse same ffmpeg instance
    // When you call exit the temporary files are deleted from MEMFS
    // If you are working with multiple inputs you can free any of the via: ffmpeg.unlink('my_input.mp4')
    ffmpeg?.exit();
  }
}

void _onProgressHandler(ProgressParam progress) {
  print('Progress: ${progress.ratio * 100}%');
}

static final regex = RegExp(
  r'frame\s*=\s*(\d+)\s+fps\s*=\s*(\d+(?:\.\d+)?)\s+q\s*=\s*([\d.-]+)\s+L?size\s*=\s*(\d+)\w*\s+time\s*=\s*([\d:\.]+)\s+bitrate\s*=\s*([\d.]+)\s*(\w+)/s\s+speed\s*=\s*([\d.]+)x',
);

void _onLogHandler(LoggerParam logger) {
  if (logger.type == 'fferr') {
    final match = regex.firstMatch(logger.message);

    if (match != null) {
      // indicates the number of frames that have been processed so far.
      final frame = match.group(1);
      // is the current frame rate
      final fps = match.group(2);
      // stands for quality 0.0 indicating lossless compression, other values indicating that there is some lossy compression happening
      final q = match.group(3);
      // indicates the size of the output file so far
      final size = match.group(4);
      // is the time that has elapsed since the beginning of the conversion
      final time = match.group(5);
      // is the current output bitrate
      final bitrate = match.group(6);
      // for instance: 'kbits/s'
      final bitrateUnit = match.group(7);
      // is the speed at which the conversion is happening, relative to real-time
      final speed = match.group(8);

      print('frame: $frame, fps: $fps, q: $q, size: $size, time: $time, bitrate: $bitrate$bitrateUnit, speed: $speed');
    }
  }
}

import 'package:cross_file/cross_file.dart';

final exportBytes = await exportVideo(inputBytes);
final xFile = XFile.fromData(exportBytes);

final controller = VideoPlayerController.network(xFile.path);