Can't rotate a video file with metadata in Flutter

[Keickd]

I need to be able to rotate a video in Flutter without re-encoding it.

In Flutter I’m using the ffmpeg_kit_flutter_new 4.1.0 plugin, and for the rotation I’m trying the following command:

ffmpeg -i input.mp4 -map_metadata 0 -metadata:s:v rotate="90" -codec copy output.mp4

This command doesn’t work for me either in the app or in the macOS version.

I discovered that changing the display_rotation property actually works, but this approach is not compatible with the Flutter version of FFmpeg 7.x.

The command that works on macOS is:

ffmpeg -display_rotation 90 -i input.mp4 -c copy output.mp4

This really rotates the video on macOS without re-encoding, but when I apply this in Flutter…

Future<void> saveVideo(XFile file) async {
    try {
      final tempDir = await getTemporaryDirectory();
      final inputPath =
          '${tempDir.path}/${DateTime.now().millisecondsSinceEpoch}_input.mp4';
      await File(file.path).copy(inputPath);

      final outputPath =
          '${tempDir.path}/${DateTime.now().millisecondsSinceEpoch}_rotated.mp4';

      final cmd =
          '-y -display_rotation 90 -i "$inputPath" -c copy "$outputPath"';

      final session = await FFmpegKit.execute(cmd);
      final returnCode = await session.getReturnCode();

      final logs = await session.getAllLogs();
      for (final log in logs) {
        _logger.info('FFmpeg', log.getMessage());
      }

      if (!ReturnCode.isSuccess(returnCode)) {
        _logger.error(
          'GalleryService',
          'Error setting display_rotation metadata: $returnCode',
        );
        throw Exception('Error setting display_rotation metadata');
      }

      final wasSuccess = await ImageGallerySaverPlus.saveFile(
        outputPath,
      ).then(_mapSavingResult);

      if (!wasSuccess) {
        _logger.error(
          'GalleryService',
          'Error saving video in gallery',
        );
        throw Exception('Error saving video in gallery');
      }
    } catch (error) {
      _logger.error(
        'GalleryService',
        'Error saving video in gallery: $error',
      );
      throw Exception('Error saving video in gallery');
    }
  }

The output of this is

I/flutter (12698): │ 💬 Display transformation (rotation/flip) not supported with FFmpeg 7.x - 
I/flutter (12698): │ 💬 displaymatrix: rotation of -90.00 degrees 

Other way of rotate the video is with exiftool but again i only found this for Desktop devices...

exiftool -m -P -api LargeFileSupport=1 -rotation=90 -o output.mp4 landscape_right.mp4

So i need a fast and performance way for changing the video rotation in metadata.
Any help would be appreciated

[kaciula]

I think this other issue is somewhat related: #121