Lightning export fails on Linux with `Cannot read properties of undefined (reading '_resourceType')`

The diagnostics point at the Lightning (Beta) export path: the crash happens before frame 0 while the WebCodecs encoder (avc1.640033, prefer-software) is being set up, and the Breeze fallback reports no Annex B H.264 support at 1440x810. Start by grepping the export backend for _resourceType and for the WebCodecs-vs-Breeze/libx264 selection, then reproduce on Linux with video encode reported as disabled_software. Done means the export renders frames, or the unsupported encoder is detected up front and libx264/Breeze is used with a clear message.

When exporting a recording using the Lightning (Beta) export option on Linux, the export fails immediately before rendering any frames.

The export dialog reports:

Cannot read properties of undefined (reading '_resourceType')

The failure occurs at 0/1589 rendered frames (0.0%), so the export does not actually begin processing the video.

The recording itself plays correctly in the editor and can be previewed normally. The issue appears specifically when attempting to export it using Lightning.

To Reproduce

Steps to reproduce the behavior:

1. Record a screen capture on Linux.
2. Open the recording in Recordly Editor.
3. Go to the Clips editor.
4. Click Export.
5. Use the Lightning (Beta) export backend.
6. Wait for the export to start.
7. The export immediately fails with:
   Cannot read properties of undefined (reading '_resourceType')

Expected behavior

The recording should be exported successfully to the selected output format.

If the requested Lightning/WebCodecs encoder path is not supported on the current Linux configuration, Recordly should ideally fall back to a supported software encoder such as libx264, or provide a clear message explaining which encoder/backend is unavailable.

Screenshots

Attached screenshot shows the Recordly Editor and the complete Export issue diagnostic panel.

The important part of the error is:

Lightning (Beta) export failed.

Reason: Cannot read properties of undefined (reading '_resourceType')

Desktop

• OS: Ubuntu Linux
• Kernel: Linux 7.0.0-29-generic (x64)
• Recordly: 1.4.0
• Runtime: Electron 43.1.0 / Chromium 150.0.7871.47
• CPU: 12th Gen Intel(R) Core(TM) i5-12500H
• RAM: 16 GB
• GPU: Intel integrated graphics
• Renderer: WebGPU
• GPU video encode: Disabled / software
• WebGL: Enabled
• WebGPU: Enabled

Export configuration

Output: 1440x810 @ 60 FPS
Bitrate: 9.05 Mbps
Mode: balanced
Requested backend mode: auto
Renderer: webgpu
Encoder path: WebCodecs
Codec: avc1.640033
Encoding preference: software/realtime

Source recording

Source codec: vp09.00.50.08.01.02.02.06.00
Resolution: 1920x1200
Frame rate: 60 FPS
Duration: 26.470s
Audio: none

Smartphone

Not applicable.

Additional context

The complete diagnostic information reported by Recordly is:

Lightning (Beta) export failed.
Reason: Cannot read properties of undefined (reading '_resourceType')
Platform: Linux
Requested backend mode: auto
Output: 1440x810 @ 60 FPS; 9.05 Mbps; mode=balanced
Recordly version: 1.4.0
Runtime: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Recordly/1.4.0 Chrome/150.0.7871.47 Safari/537.36
System: linux 7.0.0-29-generic (x64)
CPU: 12th Gen Intel(R) Core(TM) i5-12500H; 16 logical processors
Memory: 14.8 GB
GPU 1: Intel; active
GPU acceleration: video decode=enabled, video encode=disabled_software
WebGL=enabled
WebGPU=enabled

Source: vp09.00.50.08.01.02.02.06.00 1920x1200 @ 60.000 FPS; 26.470s
Source audio: none
Progress at failure: 0/1589 (0.0%) rendered frames after 0.33s
Renderer: webgpu
Encoder path: WebCodecs (avc1.640033/prefer-software/realtime)
Pipeline tuning: webcodecs-balanced-plus; decode queue=12; pending frames=32; encode queue=120

Breeze fallback:
H.264 Annex B encoding is not supported at 1440x810.

Suggested actions:
- Lightning is designed to work on macOS, Windows, and Linux, but the available encoder path depends on WebCodecs support, GPU drivers, and the bundled FFmpeg encoders.
- Check that the packaged FFmpeg build includes a compatible Breeze encoder path for Linux, plus libx264 as a software fallback.
- Linux Lightning exports can use WebCodecs when supported, or FFmpeg encoders such as libx264 and optional GPU paths depending on the distro build.

One potentially relevant detail is that video encode is reported as disabled_software, while Lightning selects the WebCodecs H.264 path. The failure occurs almost immediately, before the first frame is rendered.

I have attached a screenshot of the full error panel for reference.

the exaact error message is below :
Lightning (Beta) export failed.
Reason: Cannot read properties of undefined (reading '_resourceType')
Platform: Linux
Requested backend mode: auto
Output: 1440x810 @ 60 FPS; 9.05 Mbps; mode=balanced
Recordly version: 1.4.0
Runtime: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Recordly/1.4.0 Chrome/150.0.7871.47 Electron/43.1.0 Safari/537.36
System: linux 7.0.0-29-generic (x64)
CPU: 12th Gen Intel(R) Core(TM) i5-12500H; 16 logical processors
Memory: 14.8 GB
GPU 1: Intel; active
GPU acceleration: video decode=enabled; video encode=disabled_software; WebGL=enabled; WebGPU=enabled
Source: vp09.00.50.08.01.02.02.06.00 1920x1200 @ 60.000 FPS; 26.470s
Source audio: none
Progress at failure: 0/1589 (0.0%) rendered frames after 0.33s
Renderer: webgpu
Encoder path: WebCodecs (avc1.640033/prefer-software/realtime)
Pipeline tuning: webcodecs-balanced-plus; decode queue=12; pending frames=32; encode queue=120
Breeze fallback: H.264 Annex B encoding is not supported at 1440x810.
Suggested actions:

Lightning is designed to work on macOS, Windows, and Linux, but the available encoder path depends on WebCodecs support, GPU drivers, and the bundled FFmpeg encoders.
Check that the packaged FFmpeg build includes a compatible Breeze encoder path for Linux, plus libx264 as a software fallback.
Linux Lightning exports can use WebCodecs when supported, or FFmpeg encoders such as libx264 and optional GPU paths depending on the distro build