cottongin
8ad2f1c800
Includes: - Extended caption styling (font, shadow, dimmed color, bg toggle) - Media server, subtitle downloader, VTT parser, processing modal - Waveform tiers, thumbnail/timeline improvements, transport controls - Hybrid download model, dependency management, clip export enhancements - 21 chat summaries, 2 implementation plans, 2 design specs Co-authored-by: Cursor <cursoragent@cursor.com>
1.6 KiB
Fix Burned-In Caption Styling
Date: 2026-09-21 23:37
Task: Fix ASS styling in burn-in export to be readable and match the preview better.
Changes Made
src-tauri/src/services/clip_exporter.rs — Updated vtt_to_ass_with_karaoke() ASS style generation:
| ASS Field | Before (broken) | After (fixed) |
|---|---|---|
| OutlineColour | primary_colour (white) |
&H00000000 (black) |
| SecondaryColour | Same color with alpha &H99FFFFFF |
Distinct grey &H99AAAAAA |
| BorderStyle | 4 (opaque box) always |
1 (outline+shadow) when textOutline=true; 3 (box only) when false |
| Outline | 2 always (even with box) | 2 with BorderStyle=1; 0 with BorderStyle=3 |
Why each change matters:
-
OutlineColour=black: The preview uses
text-shadow: 1px 1px 2px rgba(0,0,0,0.9)for readability. Setting OutlineColour to white made the outline invisible against white text and washed out the karaoke fill effect. -
SecondaryColour=grey: For
\kfkaraoke, libass sweeps from SecondaryColour to PrimaryColour. With both being variants of white (just different alpha), the sweep was barely visible. Using a distinct grey (&H99AAAAAA) makes upcoming words clearly dimmed grey, sweeping to bright white when spoken. -
BorderStyle=1 vs 3:
BorderStyle=4draws an opaque background box AND renders the outline, creating a "double background" artifact.BorderStyle=1(outline+shadow, no box) matches the preview's outlined text look.BorderStyle=3(opaque box, no outline) is used when the user disables text outline, giving a clean box background.
Build Verification
cargo test— all 43 tests pass