I'm assuming that you're using the package:
https://pub.dev/packages/image_picker
pickVideo() method has been decrecated, and you will need to replace these apis with getVideo()
As explained the repositories' documentation:
https://github.com/flutter/plugins/tree/master/packages/image_picker/image_picker
Write this:
final _picker = ImagePicker();
PickedFile video = await _picker.getVideo(...)
However I would suggest to use this package as an alternative:
https://pub.dev/packages/flutter_document_picker
This package will allow you to select all videos on the device, including those taken from a users' Google Drive or iCloud providers. In this case write this:
FlutterDocumentPickerParams params = FlutterDocumentPickerParams(
allowedUtiTypes: [
'public.video',
'public.mpeg',
'public.mpeg-4-audio',
'com.apple.protected-mpeg-4-audio'
],
allowedMimeTypes: [
'video/mpeg',
'video/x-flv',
'video/mp4',
'application/x-mpegURL',
'video/quicktime',
'video/x-msvideo',
'video/x-ms-wmv',
'video/ogg',
'video/mp2t',
'video/3gpp'
],
invalidFileNameSymbols: ['/'],
);
return await FlutterDocumentPicker.openDocument(params: params);
You will need to make sure that the Mimes and Uti types for videos on iOS & Android are set correctly.