[camera] Low Resolution in Camera Image Stream, ResolutionPreset Constructor Parameter is ignored

Hi,
I would like to process images from the camera while previewing the camera images using the camera plugin. I do not want to transform the preview image or draw anything on the previewed image.
From my understanding the function CameraController#startImageStream() is supposed to be used for such tasks.
This works as expected except of the point that the images send to the image stream only have 720p resolution or lower regardless what ResolutionPreset is set when constructing the CameraController

Steps to Reproduce

Goal: Process images from the camera in best available resolution (send to isolates to not block the main isolate) while previewing the camera images.

Most important parts of the implementation:

Create controller:

_controller = CameraController(
  cameraDescription,
  ResolutionPreset.max,
  enableAudio: false,
);

Show camera preview using widget:

CameraPreview(_controller)

Listen to image stream:

_controller.startImageStream((image) {
        print("Image size: ${image.width}x${image.height}");
      });

The CameraDescription is provided by onNewCameraSelected() as demonstrated in the example provided along with this camera plugin.
To reproduce this issue you can run the example provided in this package and listen to the image stream while previewing the camera images.

Expected results: Maximum available image resolution in the image stream. My devices should have 4k resolution (or at least Full-HD).

Actual results: Always 720p (or lower if requested).

Tested Devices: Samsung Galaxy S10 and S10e

The constructor parameter of CameraController defining ResolutionPreset is ignored/overwritten if it is greater than ResolutionPreset.high.
As already pointed out in issue #49420, the following function in the camera plugin is the reason for this behavior:

static Size computeBestPreviewSize(String cameraName, ResolutionPreset preset) {
    if (preset.ordinal() > ResolutionPreset.high.ordinal()) {
      preset = ResolutionPreset.high;
    }
    CamcorderProfile profile =
        getBestAvailableCamcorderProfileForResolutionPreset(cameraName, preset);
    return new Size(profile.videoFrameWidth, profile.videoFrameHeight);
  }

I see the point that the resolution has to be scaled down for preview.
However, there should be a possibility to process the camera images in the specified resolution.
It should be up to the developer to not block the main thread when listening to an image stream.

My current workaround is to build the camera plugin locally and change CameraUtils#computeBestPreviewSize() as follows:

static Size computeBestPreviewSize(String cameraName, ResolutionPreset preset) {
    //if (preset.ordinal() > ResolutionPreset.high.ordinal()) {
    //  preset = ResolutionPreset.high;
    //}
    CamcorderProfile profile =
        getBestAvailableCamcorderProfileForResolutionPreset(cameraName, preset);
    return new Size(profile.videoFrameWidth, profile.videoFrameHeight);
  }

Of course, this now slows down the camera preview on older devices or is really slow if 4K resolution is used.
Yet, I couldn't find a way to downscale the image before being previewed using above initialization.
I was able to improve performance for previewing a little by changing line 35 of camera_preview.dart from

CameraPlatform.instance.buildPreview(controller.cameraId)

to

Texture(textureId: controller.cameraId, filterQuality: FilterQuality.none)

The default setting of the parameter filterQuality is FilterQuality.low, which is currently used.
According to the documentation of FilterQuality the setting FilterQuality.none is faster.

Summary: Is it currently possible to process the camera images with the requested resolution while previewing the camera images in a lower resolution?

If this is not the case, I would like to request the feature to add another image stream to CameraController which is not used for previewing as described above. The images in the stream used for previewing can be downscaled, that's fine.
Alternatively, one might be able to add an additional constructor parameter and field to CameraController which defines the preview size (use to downscale before actual preview) while the images send to the single image stream have the requested resolution.
Of course, if I select a large preview size the performance is bad. But this decision should be adjustable and up to the developer.

Output of `flutter-doctor -v`

[✓] Flutter (Channel stable, 2.0.2, on Linux, locale de_DE.UTF-8) • Flutter version 2.0.2 at /home/joshua/snap/flutter/common/flutter • Framework revision 8962f6d (vor 4 Tagen), 2021-03-11 13:22:20 -0800 • Engine revision 5d8bf81 • Dart version 2.12.1

[!] Android toolchain - develop for Android devices (Android SDK version 30.0.2)
• Android SDK at /home/joshua/Android/Sdk
• Platform android-30, build-tools 30.0.2
• Java binary at: /usr/lib/jvm/java-8-oracle/bin/java
• Java version Java(TM) SE Runtime Environment (build 1.8.0_201-b09)
! Some Android licenses not accepted. To resolve this, run: flutter doctor --android-licenses

[✗] Chrome - develop for the web (Cannot find Chrome executable at google-chrome)
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🔨 https://plugins.jetbrains.com/plugin/9212-flutter
• Dart plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/6351-dart

[✓] IntelliJ IDEA Ultimate Edition (version 2020.3)
• IntelliJ at /home/joshua/.local/share/JetBrains/Toolbox/apps/IDEA-U/ch-0/203.7148.57
• Flutter plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/9212-flutter
• Dart plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/6351-dart

[✓] VS Code (version 1.52.1)
• VS Code at /usr/share/code
• Flutter extension can be installed from:
🔨 https://marketplace.visualstudio.com/items?itemName=Dart-Code.flutter

[✓] Connected device (2 available)
• SM G970F (mobile) • RF8M20WXQAA • android-arm64 • Android 10 (API 29)
• SM G973F (mobile) • RF8N40DYR5Y • android-arm64 • Android 11 (API 30)

! Doctor found issues in 3 categories.

The issue #58163 seems to be related as well.

Greetings,
Joshua

@Joshua27

Thanks @Joshua27 for a detailed report. It'd be great if you could also provide a minimal reproducible code sample that we can directly use alongwith actual vs expected behavior to properly address this issue.

Thank you for the quick response. I created a minimum reproducible example which you can find here: https://github.com/Joshua27/flutter_issue_78247

Thanks for repo.

flutter doctor -v

Downloading darwin-x64/font-subset tools...                        292ms
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[✓] Connected device (3 available)
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      • com.apple.CoreSimulator.SimRuntime.iOS-14-3 (simulator)
    • macOS (desktop)            • macos                                •
      darwin-x64     • Mac OS X 10.15.4 19E2269 darwin-x64
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! Doctor found issues in 1 category.

@Joshua27

Hi @Joshua27
Thanks for filing the issue, I verified this on the latest stable and the master channel with camera: ^0.9.4+3 and the issue is reproducible.

code sample

import 'package:camera/camera.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

/// The current device's available cameras.
List<CameraDescription> cameras = [];

/// Init available cameras once on startup.
Future<void> init() async {
  WidgetsFlutterBinding.ensureInitialized();
  try {
    cameras = await availableCameras();
  } on CameraException catch (e) {
    _logError(e.code, e.description ?? '');
  }
}

void main() {
  init();
  SystemChrome.setPreferredOrientations([DeviceOrientation.portraitUp])
      .then((_) {
    runApp(MyApp());
  });
}

/// Minimal reproducible example showing that we can't get a better resolution
/// than 720p in the image stream provided by the camera plugin.
class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Camera Plugin Low Resolution',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: CameraExampleHome(),
    );
  }
}

/// Stateful widget.
class CameraExampleHome extends StatefulWidget {
  @override
  _CameraExampleHomeState createState() {
    return _CameraExampleHomeState();
  }
}

/// Returns a suitable camera icon for [direction].
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;
  }
}

void _logError(String code, String message) => print("Error #$code: $message");

class _CameraExampleHomeState extends State<CameraExampleHome>
    with WidgetsBindingObserver {
  final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();

  CameraController? _controller;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance?.addObserver(this);
  }

  @override
  void dispose() {
    WidgetsBinding.instance?.removeObserver(this);
    _controller?.dispose();
    super.dispose();
  }

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    if (_controller == null || !_controller!.value.isInitialized) {
      return;
    }
    if (state == AppLifecycleState.inactive) {
      _controller?.dispose();
    } else if (state == AppLifecycleState.resumed) {
      if (_controller != null) {
        onNewCameraSelected(_controller!.description);
      }
    }
  }

  Widget _cameraPreviewWidget() {
    if (_controller == null || !_controller!.value.isInitialized) {
      return TextButton(
          onPressed: () {},
          child: Text('Select a camera',
              style: TextStyle(
                color: Colors.black,
                fontSize: 24.0,
                fontWeight: FontWeight.w900,
              )));
    } else {
      return Stack(
        fit: StackFit.expand,
        children: <Widget>[CameraPreview(_controller!)],
      );
    }
  }

  Widget _cameraTogglesRowWidget() {
    final List<Widget> toggles = <Widget>[];

    if (cameras.isEmpty) {
      return Text("No Camera Found");
    } else {
      for (CameraDescription cameraDescription in cameras) {
        toggles.add(Expanded(
            flex: 1,
            child: RadioListTile<CameraDescription>(
              title: Icon(getCameraLensIcon(cameraDescription.lensDirection)),
              groupValue: _controller?.description,
              value: cameraDescription,
              onChanged: (CameraDescription? value) {
                onNewCameraSelected(value!);
              },
            )));
      }
    }
    return Row(children: toggles, mainAxisAlignment: MainAxisAlignment.start);
  }

  void onNewCameraSelected(final CameraDescription cameraDescription) async {
    await _controller?.dispose();

    // TODO: here we request max resolution
    _controller = CameraController(cameraDescription, ResolutionPreset.max,
        enableAudio: false);

    try {
      await _controller?.initialize();
    } on CameraException catch (e) {
      _logError(e.code, e.description ?? '');
    }

    if (mounted) {
      setState(() {});
      await _controller?.startImageStream((image) {
        // TODO: the maximum we receive here is 720p
        print("Actual image size: ${image.width}x${image.height}");
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        key: _scaffoldKey,
        appBar: AppBar(
            title: Text("Camera Plugin Low Resolution"),
            backgroundColor: Colors.white),
        body: Column(children: <Widget>[
          Expanded(
              child: Container(
                  child: Padding(
                      padding: const EdgeInsets.all(5.0),
                      child: Center(
                        child: _cameraPreviewWidget(),
                      )))),
          Padding(
              padding: const EdgeInsets.all(5.0),
              child: Center(
                child: _cameraTogglesRowWidget(),
              ))
        ]));
  }
}

flutter doctor -v

[✓] Flutter (Channel stable, 2.5.3, on macOS 11.5.2 20G95 darwin-x64, locale en-US)
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[✓] Connected device (5 available)
    • SM G975U (mobile)          • R58M95MA95E                          • android-arm64  • Android 11 (API 30)
    • sdk gphone x86 (mobile)    • emulator-5554                        • android-x86    • Android 11 (API 30) (emulator)
    • iPhone 12 Pro Max (mobile) • 98CBBFB1-4069-4A28-B7F7-138911ACBE72 • ios            • com.apple.CoreSimulator.SimRuntime.iOS-15-0
      (simulator)
    • macOS (desktop)            • macos                                • darwin-x64     • macOS 11.5.2 20G95 darwin-x64
    • Chrome (web)               • chrome                               • web-javascript • Google Chrome 93.0.4577.63

! Doctor found issues in 1 category.

[✓] Flutter (Channel master, 2.6.0-12.0.pre.470, on macOS 11.5.2 20G95 darwin-x64, locale en-US)
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[!] Android toolchain - develop for Android devices (Android SDK version 31.0.0)
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    • Platform android-31, build-tools 31.0.0
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[✓] Connected device (5 available)
    • SM G975U (mobile)          • R58M95MA95E                          • android-arm64  • Android 11 (API 30)
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Thank you

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[camera_avfoundation] Set highest available resolution for Resolution…

This workaround fixed the low-quality image preview issue for me.
I overrode the camera_android_camerax dependency to the latest version, significantly improving the preview quality.

    dependencies:
      camera: ^0.11.0+2
    dependency_overrides:
      camera_android_camerax: ^0.6.10+3

This workaround fixed the low-quality image preview issue for me. I overrode the camera_android_camerax dependency to the latest version, significantly improving the preview quality.
    dependencies:
      camera: ^0.11.0+2
    dependency_overrides:
      camera_android_camerax: ^0.6.10+3

Works for me ! Thank you 💯

[camera_avfoundation] Set highest available resolution for Resolution…

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[camera] Low Resolution in Camera Image Stream, ResolutionPreset Constructor Parameter is ignored #78247

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[camera] Low Resolution in Camera Image Stream, ResolutionPreset Constructor Parameter is ignored #78247

Description

Steps to Reproduce

Activity

darshankawar commented on Mar 16, 2021

Joshua27 commented on Mar 16, 2021

darshankawar commented on Mar 16, 2021

mamuseferha commented on Oct 26, 2021

13 remaining items

talalong commented on Jun 4, 2023

Joshua27 commented on Jun 5, 2023

kishan2612 commented on Nov 11, 2024

AwaisQazii commented on Dec 26, 2024

GregUAs commented on Feb 13, 2025

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