[camera] changing camera while recording causes a crash due to disconnected AVOutput #194344

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1. hellohuanlin

   self-assigned this

   on Oct 14, 2026
2. hellohuanlin

   added

   platform-iosiOS applications specificallyiOS applications specifically

   team-iosOwned by iOS platform teamOwned by iOS platform team

   p: cameraThe camera pluginThe camera plugin

   fyi-ecosystemFor the attention of Ecosystem teamFor the attention of Ecosystem team

   on Oct 14, 2026
3. hellohuanlin commented on Oct 14, 2026

   

   hellohuanlin

   on Oct 14, 2026

   Last edited by hellohuanlin

   ContributorAuthor

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   This is a bug in https://github.com/flutter/packages/blob/ac2db9cfeaf69c5064739e0d477ef8cb9c19cd35/packages/camera/camera_avfoundation/darwin/camera_avfoundation/Sources/camera_avfoundation/DefaultCamera.swift#L1258

   Before switching camera, the capture session has:

   Inputs:       [ backCameraInput ]
   Outputs:      [ captureVideoOutput, capturePhotoOutput ]
   Connections:
     Wire 1: backCameraInput  -> captureVideoOutput   (created manually via addConnection)
     Wire 2: backCameraInput  -> capturePhotoOutput   (created automatically via addOutput)
   

   When switching camera input, we remove video input and output, but left photo output untouched. So at this point the capture session has:

   Inputs:       [ ]
   Outputs:      [ capturePhotoOutput ]   <-- still in the session, but unplugged!
   Connections:  [ ]                      <-- both Wire 1 and Wire 2 were deleted!
   

   Now when adding back the camera input, we simply do:

   videoCaptureSession.addInputWithNoConnections(captureVideoInput)
   videoCaptureSession.addOutputWithNoConnections(captureVideoOutput.avOutput)
   

   So our capture session ends up with:

   Inputs:       [ frontCameraInput ]
   Outputs:      [ capturePhotoOutput, newVideoOutput ]
   Connections:
     Wire 1: frontCameraInput -> newVideoOutput
     Wire 2: (MISSING! capturePhotoOutput has no wire to frontCameraInput!)
   

   Then a subsequent code calls

   capturePhotoOutput.maxPhotoDimensions = maxSupportedDimensions
   

   Which throws NSInvalidArgumentException because it has no connection.

   The fix is simply change the code to videoCaptureSession.addInput(captureVideoInput), which would automatically add the frontCameraInput -> capturePhotoOutput connection.
4. vashworth

   added

   P1High-priority issues at the top of the work listHigh-priority issues at the top of the work list

   triaged-iosTriaged by iOS platform teamTriaged by iOS platform team

   on Oct 14, 2026
5. auto-submit

   closed this as completedin packages#13248on Oct 16, 2026
6. spydon

   added a commit that references this issue on Oct 16, 2026

   [camera]fix a crash when switching camera while recording due to disc…

   ...

   93eede7
7. github-actions commented on Oct 30, 2026

   

   github-actionsBot

   on Oct 30, 2026 – with GitHub Actions

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   This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.
8. github-actions

   locked as resolved and limited conversation to collaborators on Oct 30, 2026