[camera_web] Re: Support for camera stream on web#7950
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…d before expecting mock response
…d before expecting mock response
…d before expecting mock response
…d before expecting mock response
…d before expecting mock response
…d before expecting mock response
…m, and used window.animationFrames
…le height and width in takeFrame
…seOffScreenCanvas
DemoDummy example app source code 2026-04-03.19-47-24.mp4 |
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Some lints have been reported here: https://logs.chromium.org/logs/flutter/buildbucket/cr-buildbucket/8685251527310718641/+/u/Run_package_tests/analyze/stdout |
mdebbar
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ditman’s stale review
Many changes have been done since this review.
| ({int? audioBitrate, int? videoBitrate})? recorderOptions, | ||
| }) : recorderOptions = | ||
| recorderOptions ?? (audioBitrate: null, videoBitrate: null), |
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Why this change?
mockitowalks the constructor and inspects parameter defaults.- For a
constrecord literal, it goes throughsource_genconstant revival (reviveInstance). - That code path of the current version of the dependency does not handle record constants properly.
- As a result, it hits a null and throws Null check operator used on a null value.
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Ready for review |
ditman
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ditman
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This is very cool! I don't work on this nowadays, but here's some extra comments:
- Would
requestVideoFrameCallbackbe better than requestAnimationCallback? - Would it be possible to use
MediaStreamTrackProcessorif available inwindow? There's an example here: Video Frame Processing on the Web – WebAssembly, WebGPU, WebGL, WebCodecs, WebNN, and WebTransport
Anyway, very cool. Thanks for reviving this!
| // package:camera_platform_interface. | ||
| // https://github.com/flutter/flutter/issues/176148 | ||
| /// Used for running the camera frame stream at a specified FPS | ||
| final int cameraStreamFPS = 60; |
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Is this @visibleForTesting?
Also I think we should let the user know that this FPS is a maximum cap in the framerate, but not a guarantee. (Web devs should already know this, but maybe this is surprising for a mobile developer compiling for web)
| final num elapsed = timestamp - lastFrameTimestamp; | ||
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| // If we're close to the next frame (~`_frameTimeToleranceMs`), do it. | ||
| if (fpsInterval - elapsed <= _frameTimeToleranceMs) { |
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Oh! So it is NOT a maximum cap on FPS. Does this mean that at 60fps we can trigger a new frame 8ms early?
| as web.OffscreenCanvasRenderingContext2D; | ||
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| _offscreenCanvasContext!.drawImage(videoElement, 0, 0); | ||
| imageData = _offscreenCanvasContext!.getImageData(0, 0, width, height); |
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Can you please split the behavior of taking an offscreen frame vs the fallback into two smaller methods? _takeOffscreenCanvasFrame and _takeFallbackCanvasFrame (both return imageData). That way the takeFrame method becomes smaller?
| final ByteBuffer byteBuffer = imageData.data.toDart.buffer; | ||
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| return CameraImageData( | ||
| format: const CameraImageFormat(ImageFormatGroup.unknown, raw: 0), |
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Would it make sense to extend the ImageFormatGroup to better describe what the browser is capturing here?
(There's also settings for getImageData that may be used here to capture frames in a "less unknown" format, maybe?)
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This PR aims to provide support for strartImageStream and stopImageStream on Web.
#92460
Based on #6944 from the archived plugins repository
Pre-launch Checklist
dart format.)[shared_preferences]pubspec.yamlwith an appropriate new version according to the [pub versioning philosophy], or this PR is [exempt from version changes].CHANGELOG.mdto add a description of the change, [following repository CHANGELOG style].///).POV: my first PR on a public repo
Contains required commits from the PR #6443, resolves unnecessary 202 commits