Capture video with flutter

Flutter provides a packages "camera" and "video_player". Camera is used for accessing the camera of the phone and video_plater is used for video recording. You can use the camera package and record the video. You can find the code below:

First you have to update the pubspec file like:

dependencies:
   camera: ^0.2.9+1
   fluttertoast: 
   path_provider:
   video_player:

fluttertoast is the toast for your camera and path_provider provides that path where your video will be saved. Then you have to import those packages into your dart file and write your own implementation. you can find the sample code below. It opens the available list of cameras in your phone including the external cameras so that you can choose any one of them to record your video.

import 'dart:async';
  import 'dart:io';

  import 'package:camera/camera.dart';
  import 'package:flutter/material.dart';
  import 'package:path_provider/path_provider.dart';
  import 'package:video_player/video_player.dart';
  import 'package:fluttertoast/fluttertoast.dart';

  class VideoRecorderExample extends StatefulWidget {
    @override
    _VideoRecorderExampleState createState() {
      return _VideoRecorderExampleState();
    }
  }

  class _VideoRecorderExampleState extends State<VideoRecorderExample> {
    CameraController controller;
    String videoPath;

    List<CameraDescription> cameras;
    int selectedCameraIdx;

    final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();

    @override
    void initState() {
      super.initState();

      // Get the listonNewCameraSelected of available cameras.
      // Then set the first camera as selected.
      availableCameras()
          .then((availableCameras) {
        cameras = availableCameras;

        if (cameras.length > 0) {
          setState(() {
            selectedCameraIdx = 0;
          });

          _onCameraSwitched(cameras[selectedCameraIdx]).then((void v) {});
        }
      })
          .catchError((err) {
        print('Error: $err.code\nError Message: $err.message');
      });
    }

    @override
    Widget build(BuildContext context) {
      return Scaffold(
        key: _scaffoldKey,
        appBar: AppBar(
          title: const Text('Camera example'),
        ),
        body: Column(
          children: <Widget>[
            Expanded(
              child: Container(
                child: Padding(
                  padding: const EdgeInsets.all(1.0),
                  child: Center(
                    child: _cameraPreviewWidget(),
                  ),
                ),
                decoration: BoxDecoration(
                  color: Colors.black,
                  border: Border.all(
                    color: controller != null && controller.value.isRecordingVideo
                        ? Colors.redAccent
                        : Colors.grey,
                    width: 3.0,
                  ),
                ),
              ),
            ),
            Padding(
              padding: const EdgeInsets.all(5.0),
              child: Row(
                mainAxisAlignment: MainAxisAlignment.start,
                children: <Widget>[
                  _cameraTogglesRowWidget(),
                  _captureControlRowWidget(),
                  Expanded(
                    child: SizedBox(),
                  ),
                ],
              ),
            ),
          ],
        ),
      );
    }

    IconData _getCameraLensIcon(CameraLensDirection direction) {
      switch (direction) {
        case CameraLensDirection.back:
          return Icons.camera_rear;
        case CameraLensDirection.front:
          return Icons.camera_front;
        case CameraLensDirection.external:
          return Icons.camera;
        default:
          return Icons.device_unknown;
      }
    }

    // Display 'Loading' text when the camera is still loading.
    Widget _cameraPreviewWidget() {
      if (controller == null || !controller.value.isInitialized) {
        return const Text(
          'Loading',
          style: TextStyle(
            color: Colors.white,
            fontSize: 20.0,
            fontWeight: FontWeight.w900,
          ),
        );
      }

      return AspectRatio(
        aspectRatio: controller.value.aspectRatio,
        child: CameraPreview(controller),
      );
    }

    /// Display a row of toggle to select the camera (or a message if no camera is available).
    Widget _cameraTogglesRowWidget() {
      if (cameras == null) {
        return Row();
      }

      CameraDescription selectedCamera = cameras[selectedCameraIdx];
      CameraLensDirection lensDirection = selectedCamera.lensDirection;

      return Expanded(
        child: Align(
          alignment: Alignment.centerLeft,
          child: FlatButton.icon(
              onPressed: _onSwitchCamera,
              icon: Icon(
                  _getCameraLensIcon(lensDirection)
              ),
              label: Text("${lensDirection.toString()
                  .substring(lensDirection.toString().indexOf('.')+1)}")
          ),
        ),
      );
    }

    /// Display the control bar with buttons to record videos.
    Widget _captureControlRowWidget() {
      return Expanded(
        child: Align(
          alignment: Alignment.center,
          child: Row(
            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
            mainAxisSize: MainAxisSize.max,
            children: <Widget>[
              IconButton(
                icon: const Icon(Icons.videocam),
                color: Colors.blue,
                onPressed: controller != null &&
                    controller.value.isInitialized &&
                    !controller.value.isRecordingVideo
                    ? _onRecordButtonPressed
                    : null,
              ),
              IconButton(
                icon: const Icon(Icons.stop),
                color: Colors.red,
                onPressed: controller != null &&
                    controller.value.isInitialized &&
                    controller.value.isRecordingVideo
                    ? _onStopButtonPressed
                    : null,
              )
            ],
          ),
        ),
      );
    }

    String timestamp() => DateTime.now().millisecondsSinceEpoch.toString();

    Future<void> _onCameraSwitched(CameraDescription cameraDescription) async {
      if (controller != null) {
        await controller.dispose();
      }

      controller = CameraController(cameraDescription, ResolutionPreset.high);

      // If the controller is updated then update the UI.
      controller.addListener(() {
        if (mounted) {
          setState(() {});
        }

        if (controller.value.hasError) {
          Fluttertoast.showToast(
              msg: 'Camera error ${controller.value.errorDescription}',
              toastLength: Toast.LENGTH_SHORT,
              gravity: ToastGravity.CENTER,
              timeInSecForIos: 1,
              backgroundColor: Colors.red,
              textColor: Colors.white
          );
        }
      });

      try {
        await controller.initialize();
      } on CameraException catch (e) {
        _showCameraException(e);
      }

      if (mounted) {
        setState(() {});
      }
    }

    void _onSwitchCamera() {
      selectedCameraIdx = selectedCameraIdx < cameras.length - 1
          ? selectedCameraIdx + 1
          : 0;
      CameraDescription selectedCamera = cameras[selectedCameraIdx];

      _onCameraSwitched(selectedCamera);

      setState(() {
        selectedCameraIdx = selectedCameraIdx;
      });
    }

    void _onRecordButtonPressed() {
      _startVideoRecording().then((String filePath) {
        if (filePath != null) {
          Fluttertoast.showToast(
              msg: 'Recording video started',
              toastLength: Toast.LENGTH_SHORT,
              gravity: ToastGravity.CENTER,
              timeInSecForIos: 1,
              backgroundColor: Colors.grey,
              textColor: Colors.white
          );
        }
      });
    }

    void _onStopButtonPressed() {
      _stopVideoRecording().then((_) {
        if (mounted) setState(() {});
        Fluttertoast.showToast(
            msg: 'Video recorded to $videoPath',
            toastLength: Toast.LENGTH_SHORT,
            gravity: ToastGravity.CENTER,
            timeInSecForIos: 1,
            backgroundColor: Colors.grey,
            textColor: Colors.white
        );
      });
    }

    Future<String> _startVideoRecording() async {
      if (!controller.value.isInitialized) {
        Fluttertoast.showToast(
            msg: 'Please wait',
            toastLength: Toast.LENGTH_SHORT,
            gravity: ToastGravity.CENTER,
            timeInSecForIos: 1,
            backgroundColor: Colors.grey,
            textColor: Colors.white
        );

        return null;
      }

      // Do nothing if a recording is on progress
      if (controller.value.isRecordingVideo) {
        return null;
      }

      final Directory appDirectory = await getApplicationDocumentsDirectory();
      final String videoDirectory = '${appDirectory.path}/Videos';
      await Directory(videoDirectory).create(recursive: true);
      final String currentTime = DateTime.now().millisecondsSinceEpoch.toString();
      final String filePath = '$videoDirectory/${currentTime}.mp4';

      try {
        await controller.startVideoRecording(filePath);
        videoPath = filePath;
      } on CameraException catch (e) {
        _showCameraException(e);
        return null;
      }

      return filePath;
    }

    Future<void> _stopVideoRecording() async {
      if (!controller.value.isRecordingVideo) {
        return null;
      }

      try {
        await controller.stopVideoRecording();
      } on CameraException catch (e) {
        _showCameraException(e);
        return null;
      }
    }

    void _showCameraException(CameraException e) {
      String errorText = 'Error: ${e.code}\nError Message: ${e.description}';
      print(errorText);

      Fluttertoast.showToast(
          msg: 'Error: ${e.code}\n${e.description}',
          toastLength: Toast.LENGTH_SHORT,
          gravity: ToastGravity.CENTER,
          timeInSecForIos: 1,
          backgroundColor: Colors.red,
          textColor: Colors.white
      );
    }
  }

  class VideoRecorderApp extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      return MaterialApp(
        home: VideoRecorderExample(),
      );
    }
  }

  Future<void> main() async {
    runApp(VideoRecorderApp());
  }