Stuck at "Rendering video"

[mxvsh]

Description

Export feature isn't working, stay stuck forever

Reproduction

Click Export

Additional Context

• Cap version: 0.4.7
• Operating system, version: mac 26.3

[linear]

CAP-645

[Hona]

yeah I'm getting this as well

[tembo]

This looks related to several export issues that have been reported on macOS in the 0.4.x series:

• #436 - Export stuck on "Preparing to render" (macOS, 0.3.39) - was fixed
• #1511 - Export very slow with frame decode timeouts (macOS, 0.4.3)
• #1515 - "Sending frame to channel failed" during export (Windows, 0.4.0-0.4.3)

The export pipeline in crates/export/src/mp4.rs uses frame channels and async rendering. When these get stuck at 0%, it typically indicates the frame decode/render pipeline isn't starting properly.

Troubleshooting suggestions:

1. Check if logs exist at ~/Library/Logs/so.cap.desktop/ - the log files would help identify where the pipeline is stalling
2. Try quitting Cap completely and relaunching before exporting
3. If the recording has audio, try muting audio in export settings to isolate whether it's a video or audio pipeline issue

For maintainers: The export code path starts in crates/export/src/mp4.rs:51 (Mp4ExportSettings::export) and the frame rendering happens via cap_rendering. The 0% stuck state suggests the renderer setup or first frame decode may be failing silently. Adding more granular progress events before the main render loop could help diagnose where exactly it's stalling.

[mxvsh]

The issue is fixed in v0.4.71