Installed com.oneplus.camera exported from the OxygenOS, installed it on LineageOS. Works fine, except when phone is turned landscape, the app crashes:

01-27 06:10:16.516 28226 28226 V OrientationManager: onRotationChanged() - PORTRAIT -> LANDSCAPE
01-27 06:10:16.516 28226 28226 V SensorFocusControllerImpl: onAccelerometerValuesChanged() - isMoved
01-27 06:10:16.517  1142  1142 E OMXNodeInstance: getConfig(0xf218a0c4:qcom.encoder.avc, ??(0x7f000062)) ERROR: UnsupportedSetting(0x80001019)
01-27 06:10:16.520 28226 28226 D OPCameraActivity: [Property] Rotation(id=68) : PORTRAIT -> LANDSCAPE
01-27 06:10:16.520  1142  1142 E OMXNodeInstance: getParameter(0xf218a0c4:qcom.encoder.avc, ParamConsumerUsageBits(0x6f800004)) ERROR: UnsupportedIndex(0x8000101a)
01-27 06:10:16.521   794 28362 E mm-camera: <IFACE ><ERROR> 2789: iface_axi_proc_subdev_event: Received ISP_EVENT_SOF for frame_id 7 on src 0
01-27 06:10:16.521   794 28362 E mm-camera: <IFACE ><ERROR> 2399: iface_axi_handle_sof_event: Event SOF session 4 VFE0, src 0 with frame_id 7
01-27 06:10:16.521   794 28362 E mm-camera: <IFACE ><ERROR> 9224: iface_util_hw_notify_sof: iface_util_hw_notify_sof: session 4 frame_id 7 frame_src = 0
01-27 06:10:16.521   794 28362 E mm-camera: <ISP   ><ERROR> 237: isp_handler_sof:  E frame_id 7, svhdr_enable = 0
01-27 06:10:16.521   794 28362 E mm-camera: <MCT   ><ERROR> 476: mct_module_post_bus_msg: About to post MCT_BUS_MSG_ISP_SOF
01-27 06:10:16.521   794 28362 E mm-camera: <MCT   ><ERROR> 270: mct_bus_post_msg: Posting SOF for frame ID 7 session = 4
01-27 06:10:16.521  1142  1142 D GraphicBufferSource: setting dataspace: 0x104, acquired=0
01-27 06:10:16.521  1142  1142 E OMXNodeInstance: getParameter(0xf218a0c4:qcom.encoder.avc, ParamConsumerUsageBits(0x6f800004)) ERROR: UnsupportedIndex(0x8000101a)
01-27 06:10:16.522 28226 28226 D AndroidRuntime: Shutting down VM
01-27 06:10:16.522  1142  1142 D GraphicBufferSource: requesting color aspects (R:2(Limited), P:1(BT709_5), M:1(BT709_5), T:3(SMPTE170M))
01-27 06:10:16.522   794 28305 E mm-camera: <MCT   ><ERROR> 1243: mct_controller_handle_SOF_proc: Received SOF @ MCT thread for frame id 7
--------- beginning of crash
01-27 06:10:16.522 28226 28226 E AndroidRuntime: FATAL EXCEPTION: main
01-27 06:10:16.522 28226 28226 E AndroidRuntime: Process: com.oneplus.camera, PID: 28226
01-27 06:10:16.522 28226 28226 E AndroidRuntime: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.oneplus.widget.FilmstripView.setDisplayRotationHint(com.oneplus.base.Rotation)' on a null
 object reference
01-27 06:10:16.522 28226 28226 E AndroidRuntime:        at com.oneplus.gallery.CameraGalleryImpl.updateRotation(CameraGalleryImpl.java:6583)
01-27 06:10:16.522 28226 28226 E AndroidRuntime:        at com.oneplus.gallery.CameraGalleryImpl.onRotationChanged(CameraGalleryImpl.java:4586)
01-27 06:10:16.522 28226 28226 E AndroidRuntime:        at com.oneplus.camera.UIComponent$4.onPropertyChanged(UIComponent.java:109)
01-27 06:10:16.522 28226 28226 E AndroidRuntime:        at com.oneplus.base.BasicBaseObject.callPropertyChangedCallback(BasicBaseObject.java:210)
01-27 06:10:16.522 28226 28226 E AndroidRuntime:        at com.oneplus.base.BaseObjectAdapter.callPropertyChangedCallback(BaseObjectAdapter.java:46)
01-27 06:10:16.522 28226 28226 E AndroidRuntime:        at com.oneplus.base.BasicBaseObject.notifyPropertyChanged(BasicBaseObject.java:405)
01-27 06:10:16.522 28226 28226 E AndroidRuntime:        at com.oneplus.base.BasicBaseObject.notifyPropertyChanged(BasicBaseObject.java:330)
01-27 06:10:16.522 28226 28226 E AndroidRuntime:        at com.oneplus.base.BaseObjectAdapter.notifyPropertyChanged(BaseObjectAdapter.java:70)
01-27 06:10:16.522 28226 28226 E AndroidRuntime:        at com.oneplus.base.BaseActivity.notifyPropertyChanged(BaseActivity.java:661)
01-27 06:10:16.522 28226 28226 E AndroidRuntime:        at com.oneplus.camera.CameraActivity.notifyUIRotationChanged(CameraActivity.java:3422)
01-27 06:10:16.522 28226 28226 E AndroidRuntime:        at com.oneplus.camera.CameraActivity.onRotationChanged(CameraActivity.java:5450)
01-27 06:10:16.522 28226 28226 E AndroidRuntime:        at com.oneplus.camera.CameraActivity$49.onRotationChanged(CameraActivity.java:7199)
01-27 06:10:16.522 28226 28226 E AndroidRuntime:        at com.oneplus.base.OrientationManager$CallbackHandler.handleMessage(OrientationManager.java:127)
01-27 06:10:16.522 28226 28226 E AndroidRuntime:        at android.os.Handler.dispatchMessage(Handler.java:107)
01-27 06:10:16.522 28226 28226 E AndroidRuntime:        at android.os.Looper.loop(Looper.java:214)
01-27 06:10:16.522 28226 28226 E AndroidRuntime:        at android.app.ActivityThread.main(ActivityThread.java:7356)
01-27 06:10:16.522 28226 28226 E AndroidRuntime:        at java.lang.reflect.Method.invoke(Native Method)
01-27 06:10:16.522 28226 28226 E AndroidRuntime:        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:491)
01-27 06:10:16.522 28226 28226 E AndroidRuntime:        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:940)
01-27 06:10:16.522   794 28305 E mm-camera: <MCT   ><ERROR> 1143: mct_stream_map_frame_number: SOF 7: Book-keeping (frame_num, ack_frame_id) = [806, 10] in list
01-27 06:10:16.522   794 28305 E mm-camera: <SENSOR><ERROR> 510: module_sensor_handle_sof_notify: identity=0x4000f, frame_id=7, stream_type = 11
01-27 06:10:16.523   794 28305 E mm-camera: <ISP   ><ERROR> 427: isp_handler_control_sof:  E 7
01-27 06:10:16.523   794 28305 E mm-camera: <SENSOR><ERROR> 1035: sensor_apply_exposure: ctrl:0xf0c5d300,cur_gain=448, applied gain=448, cur_linecount=6498, fl_lines=6508,0,0,exp_time:0.000000
01-27 06:10:16.523   794 28305 E mm-camera: <SENSOR><ERROR> 1124: sensor_apply_exposure: Sensor imx398, cur_FPS 16.641058, cur_gain=448, applied gain=448, cur_linecount=6498, fl_lines=6508
01-27 06:10:16.524   794 28305 E mm-camera: <SENSOR><ERROR> 497: port_sensor_handle_aec_update: flash_process  est_state= 0 ,state =0 ,torch_on =0, partial_flash_frame_skip =1, is_dual_cam = 0
01-27 06:10:16.525  1484 12067 W ActivityTaskManager:   Force finishing activity com.oneplus.camera/.OPCameraActivity
01-27 06:10:16.526   794 28329 E         : VIDIOC_DQBUF buf_index 6, frame_idx 6, stream type 7, rc 0,queued: 17, buf_type = 0 flags = 8192 FD = 172 my_num 0 buf fd 230
01-27 06:10:16.527   794 28356 E         : VIDIOC_QBUF buf_index 6, frame_idx 6 stream type 7, rc 0, queued: 18, buf_type = 0 stream-FD = 172 my_num 0 buf fd: 230
01-27 06:10:16.530  1484 28396 I DropBoxManagerService: add tag=data_app_crash isTagEnabled=true flags=0x2
01-27 06:10:16.530   794   794 E         : VIDIOC_QBUF buf_index 9, frame_idx 6 stream type 1, rc 0, queued: 4, buf_type = 0 stream-FD = 181 my_num 0 buf fd: 317
01-27 06:10:16.543  1484  1519 I ActivityManager: Showing crash dialog for package com.oneplus.camera u0

Installing com.oneplus.gallery (also pulled from OxygenOS) seems to solve the problem.

I didn’t find any meaningful reference in the stock OS or interwebs of com.oneplus.base, thus I couldn’t try using that.
On the stock OS, disabling the stock gallery app leaves the camera app working. This could be due to com.oneplus.base being available as an another backend, or the gallery app being installed, even though it’s disabled.