- Include `resolvedWebcamVideoUrl` in the dependency arrays for
`captureProjectThumbnail` and `handleExport` so thumbnail capture and
export settings stay in sync when the webcam URL refreshes.
- Clear `VideoMuxer.streamSink` before awaiting `closeIpcExportStream`
in `finalize()` to close the race where a concurrent `destroy()` →
`abortStream()` could try to close the same stream ID a second time.
Long recordings (35-minute screencaps were the motivating case) fail at
the 99% "Finalizing" step with a RangeError once the muxed MP4 would
exceed V8's ~2 GiB per-ArrayBuffer limit. Both export paths accumulate
the whole file in renderer memory and round-trip it through IPC, so no
output size past that point can complete:
- Legacy: src/lib/exporter/muxer.ts uses mediabunny's BufferTarget,
which holds the entire MP4 in a single ArrayBuffer. finalize() → Blob
→ blob.arrayBuffer() → ipcRenderer.invoke('write-exported-video-to-
path', arrayBuffer, path) — every step wants a ≥2 GiB contiguous
allocation.
- Lightning: native-video-export-finish did fs.readFile(finalizedPath)
and shipped the bytes back to the renderer, which re-serialized them
again. Same ceiling.
This change moves the finished MP4 across the renderer↔main boundary
via a temp file instead of an ArrayBuffer:
- New electron/ipc/export/exportStream.ts manages streaming temp files
via fh.write(buf, 0, len, position) so out-of-order writes (moov box
rewrites, etc.) stay safe. Each session lives in a 0700 mkdtemp()
directory opened with O_CREAT | O_EXCL so a hostile local user on a
shared tempdir cannot pre-plant a symlink at the predicted path.
- New renderer-facing IPCs: export-stream-open/write/close,
finalize-exported-video (renames temp to final path, copy+unlink
fallback on EXDEV/EPERM/ENOTEMPTY with console.warn on leaked bytes),
mux-exported-video-audio-from-path (FFmpeg audio fallback that takes
a path instead of an ArrayBuffer), and discard-exported-temp. Every
handler validates the caller-supplied path against an owned-export-
paths registry before touching disk, so a compromised renderer cannot
route arbitrary filesystem paths into main-process deletes/moves.
- The muxer now picks mediabunny's StreamTarget automatically when the
Electron bridge is available (BufferTarget stays for tests and any
non-Electron callers). finalize() returns { mode, tempFilePath,
bytesWritten } or { mode, blob } so the exporter can branch.
- Exporters forward tempFilePath through ExportResult. Lightning's
finish returns the ffmpeg temp path directly; the FFmpeg audio
fallback forks on the muxer result type. modernVideoExporter's
Lightning success branch now accepts tempFilePath (previously it
checked blob only, which regressed every native export).
- VideoEditor.tsx dispatches on tempFilePath: finalize via the new IPC,
keep the temp in place when the save dialog is canceled so "Save
Again" still works without re-rendering, keep the pending-save entry
alive on non-canceled save failures, and discard the temp on unmount
or explicit clear. GIF and smoke-test code paths still use the
legacy Blob path unchanged.
- app.on('before-quit') also reaps any open streaming sessions via
cleanupAllExportStreams().
Chunk size is 16 MiB — well under Electron/Mojo IPC message limits
while keeping total writes low (~160 for a 2.5 GB export).
Tested locally: exported a 35:13 source (~2.7 GiB H.264 input) at
Original 1920×1080 + Balanced. Previously failed on finalize with a
RangeError; with this patch the Legacy pipeline produced a valid 3.7
GiB MP4 whose ffmpeg -i duration/streams match the source.
Addresses #194.
- Change ?? 99 fallback to ?? 100 in finalizing progress label
- Add editor.export.processingAudioEdits i18n key to all 5 locales
- Tighten sourceTimeToOutputTime return type to number (was number|null)
- Remove now-unused totalOutputDurationMs param from scheduleRegionForChunk
- Remove ?? fallbacks at call sites (function always returns a number)
- Fall back to video container duration when mainBuffer is null but
audioRegions are present (prevents empty output)
- Use data.numberOfChannels as deinterleave stride instead of capped
dataChannels (fixes garbled audio for 5.1+ sources)
- Fix .coderabbit.yaml: '*' is not valid regex, use '.*'
- Add encoderError check after awaiting pendingMuxing to prevent
finalization of corrupt exports (both exporters)
- Remove unreachable synchronous fast-path in getMediaDurationSec
- Set preload='metadata' before src for correct browser behavior
- Localize audio processing status text with t()
Major rewrite of the audio export pipeline for stability and memory efficiency:
## Streaming Decode
- Primary decode path uses WebDemuxer + AudioDecoder (WebCodecs streaming)
- Falls back to bulk decodeAudioData if streaming fails
- Avoids holding full compressed file + decoded PCM simultaneously
## Chunked Offline Rendering
- Processes timeline in 30-second OfflineAudioContext chunks
- Memory bounded to ~30s of PCM per chunk regardless of recording length
## Chunked WAV Writing
- Writes PCM in ~256KB chunks instead of single massive ArrayBuffer
- Eliminates OOM for long recordings on the native/FFmpeg export path
## Chunked Encoding
- Single AudioEncoder kept alive across all chunks (clean AAC stream)
- Proper backpressure and error propagation per chunk
## scheduleBufferThroughTimeline chunk windowing
- Clips source nodes to chunk boundaries for correct cross-chunk audio
- Backwards compatible defaults when no chunk params provided
## Other export fixes
- Progress cap: 99% -> 100% in both exporters and UI
- Muxing errors: propagated instead of silently swallowed
- Mac recording: enhanced warning when no audio files for muxing
- Export timeout: eliminated by removing real-time rendering
- IPC get-local-media-url now checks both fs.realpath and path.resolve forms
against approvedLocalReadPaths, so symlinks approved via approveUserPath work
- Extract duplicated sync correction parameters into shared constants in
audioEncoder.ts (SYNC_SEEK_THRESHOLD_SEC, SYNC_PLAYBACK_RATE_OPTIONS)
- Fix telemetry drift reset: use nextExpectedMs - now for delay instead
of stale drift value after baseline reset (avoids 1ms rapid sample)
- Use RECORDER_TIMESLICE_MS for mic fallback recorder (was hardcoded 1000)
- Return requested timeMs in extensionHost getCursorAt boundary clamps
- Remove premature null of webcam URL to prevent flicker on path change
- Use fs.realpath in IPC get-local-media-url to match media server check
- Replace setInterval with drift-compensating recursive setTimeout for
cursor sampling. Under CPU load setInterval bunches or skips callbacks,
creating irregular gaps in telemetry data.
- Add binary search + linear interpolation to export cursor lookup
(modernFrameRenderer) matching the playback path. Was using O(n)
nearest-neighbor which caused visible cursor jumping in exports.
- Apply same interpolation fix to extension API getCursorAt().
- Always route audio through aresample=async=1:first_pts=0 filter during
muxing on both macOS and Windows, even when duration delta is small.
Previously skipped when delta ≤50ms, which left progressive clock drift
(from CPU load) completely uncorrected.
- Lower sync detection threshold from 50ms to 20ms so tempo correction
kicks in earlier.
- Use explicit 48kHz AudioContext sample rate in both browser recording
and export rendering to prevent sample rate mismatch drift.
- Reduce MediaRecorder timeslice from 1000ms to 250ms to reduce chunk
loss under CPU pressure.
- Tighten export audio sync: seek threshold 300ms→150ms, tolerance
15ms→8ms, correction window 2s→0.5s, max adjustment ±8%→±12%.
- Lower companion audio start delay threshold from 50ms to 25ms.
- Integrate extension render hooks into frameRenderer and modernFrameRenderer
- Add modernFrameRenderer for compositing extensions during export
- Wire extension audio processing in audioEncoder
- Support extension hooks in gif and video export paths
- Extension loader with manifest validation, ID sanitization, and path traversal protection
- Permission-gated runtime API (render, cursor, audio, timeline, ui, assets, export)
- Extension host with lifecycle management (activate/deactivate)
- Marketplace client for browsing, downloading, and installing extensions
- Extension Manager UI panel with enable/disable/uninstall
- IPC bridge for extension discovery, management, and marketplace operations
- Proxy guard on window.electronAPI to block extension access to privileged IPC
- Zip-slip protection via post-extraction directory traversal validation
- Safe PowerShell invocation for Windows zip extraction (no string interpolation)
- File URL resolution with path escape prevention