使用颤动从视频创建缩略图时图像无效

问题描述

尝试从视频生成缩略图图像，文件已创建，但加载时错误为无效图像。使用此包 video_thumbnail

创建缩略图，

Future<File> genThumbnail(url) async {
    //WidgetsFlutterBinding.ensureInitialized();
    Uint8List bytes;
    final Completer<ThumbnailResult> completer = Completer();
      bytes = await VideoThumbnail.thumbnailData(
          video: url,imageFormat: ImageFormat.JPEG,maxHeight: 250,maxWidth: 300,timeMs: 0,quality: 0);

    int _imageDataSize = bytes.length;
    print("image size: $_imageDataSize");

    //final _image = Image.memory(bytes);
    //var _file =File.fromrawPath(bytes);

    Directory tempDir = await getTemporaryDirectory();
    var uint8list = bytes;
    var buffer = uint8list.buffer;
    ByteData byteData = ByteData.view(buffer);
    File file = await File('${tempDir.path}/img/THUMBNAIL${DateTime.Now().toIso8601String()}.JPEG').writeAsBytes(
        buffer.asUint8List(byteData.offsetInBytes,byteData.lengthInBytes));

    return file;
  }

保存到 firestore

await genThumbnail(fileurl).then((_thumbFIle) async{
          String Thumbfileurl = await uploadFile(_thumbFIle,'thumbnailOf${filenamewithoutExtension}.JPEG','videothumbnail');
          await sendFiletoFirestoreChat(fileType,fileurl,filenamewithoutExtension,Thumbfileurl);
          return fileurl;
        });

保存的图像， https://firebasestorage.googleapis.com/v0/b/proj-inhouse.appspot.com/o/videos%2Fvideothumbnails%2FthumbnailOfVID-20210301-WA0006.JPEG?alt=media&token=fa4f23c1-601f-486b-97d1-c63e221166af

解决方法

将此作为社区 Wiki 发布，因为它基于 @pskink 评论。

要解决，请添加 writeAsBytes(buffer.asUint8List()) 而不是 buffer。不需要任何 .edmx。