Fix merge timeout: O(D) trim+overlay+concat replaces O(N×D) chained overlays#3
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anoob-optiroai wants to merge 2 commits into
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Fix merge timeout: O(D) trim+overlay+concat replaces O(N×D) chained overlays#3anoob-optiroai wants to merge 2 commits into
anoob-optiroai wants to merge 2 commits into
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- Switch from macos-latest (arm64/Apple Silicon) to macos-13 (Intel x64) because electron-builder has a known hdiutil/background.tiff crash on arm64 - Set dmg.background: null to avoid the .background/background.tiff lookup - Set hardenedRuntime: false (no signing cert configured) - Build separate x64 and arm64 DMG targets (cross-compiled from Intel runner) Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
The old _apply_alpha_transitions chained N overlay filters on the full base video, making FFmpeg do O(N × duration) encoding work. With 30 transitions on a 47-minute video this exceeded the 900 s timeout. The new approach splits the base video into segments in a single FFmpeg pass, applies each transition overlay only to its ~1.2 s window, then concatenates — O(duration) work regardless of transition count. Also uses integer frame arithmetic for cut_times (zero float drift) and scales timeout to 5× video duration (min 30 min) to handle long presentations gracefully. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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Summary
_apply_alpha_transitionschained N overlay filters on the full base video. FFmpeg had to encode the entire video N times (once per overlay link in the chain). With 30 transitions on a 47-minute video, that's ~24 hours of encoding work — impossible within the 900 s timeout.frame_acc += fcin integer counts,cut_times.append(frame_acc / FPS)) instead oft_acc += dfloat accumulation — eliminates sync drift at 6-7 minutes.max(1800, base_dur × 5)seconds so long presentations are handled gracefully.Test plan
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