Created AUTHOR_MODULE.md covering all features in detail:
Chapter Detection:
- How scene detection works (FFmpeg filter threshold)
- Sensitivity slider guide (0.1-0.9 range explained)
- Visual preview feature with thumbnails
- Use cases for different video types
- Technical implementation details
DVD Timestamp Correction:
- SCR backwards error explanation
- Automatic remux solution (-fflags +genpts)
- Why it's needed and how it works
- Performance impact (negligible)
Authoring Log Viewer:
- Tail behavior (last 100 lines)
- Performance optimizations explained
- Copy Log and View Full Log buttons
- Memory usage improvements (O(1) vs O(n))
Complete Workflows:
- Single movie to DVD
- TV series multi-title disc
- Concert with manual chapters
Troubleshooting:
- SCR errors
- Too many/few chapters detected
- UI lag issues (now fixed)
- ISO burning problems
- Playback stuttering
Technical Details:
- Full encoding pipeline with commands
- Chapter XML format
- Temporary file locations
- Dependencies and installation
- File size estimates for NTSC/PAL
Also updated DVD_USER_GUIDE.md:
- Removed branding footer
- Added reference to AUTHOR_MODULE.md for technical details
Allows visual verification of detected scene changes before accepting.
Features:
- Extracts thumbnail at each detected chapter timestamp
- Displays first 24 chapters in scrollable grid (4 columns)
- Shows timestamp below each thumbnail (160x90px previews)
- Accept/Reject buttons to confirm or discard detection
- Progress indicator during thumbnail generation
Implementation:
- showChapterPreview() function creates preview dialog
- extractChapterThumbnail() uses FFmpeg to extract frame
- Scales to 320x180, saves as JPEG in temp dir
- Thumbnails generated in background, dialog updated when ready
Performance:
- Limits to 24 chapters for UI responsiveness
- Shows "(showing first 24)" if more detected
- Temp files stored in videotools-chapter-thumbs/
User workflow:
1. Adjust sensitivity slider
2. Click "Detect Scenes"
3. Review thumbnails to verify detection quality
4. Accept to use chapters, or Reject to try different sensitivity
Problem: Author log was causing severe UI lag and memory issues
- Unbounded string growth (entire log kept in RAM)
- Full widget rebuild on every line append
- O(n²) string concatenation performance
Solutions implemented:
1. Tail behavior - Keep only last 100 lines in UI
- Uses circular buffer (authorLogLines slice)
- Prevents unbounded memory growth
- Rebuilds text from buffer on each append
2. Copy Log button
- Copies full log from file (accurate)
- Falls back to in-memory log if file unavailable
3. View Full Log button
- Opens full log in dedicated log viewer
- No UI lag from large logs
4. Track log file path
- authorLogFilePath stored when log created
- Used by copy and view buttons
Performance improvements:
- Memory: O(1) instead of O(n) - fixed 100 line buffer
- CPU: One SetText() per line instead of concatenation
- UI responsiveness: Dramatically improved with tail behavior
UI changes:
- Label shows "Authoring Log (last 100 lines)"
- Copy/View buttons for accessing full log
DVD Authoring Fix:
- Add remultiplex step after MPEG encoding for DVD compliance
- Use ffmpeg -fflags +genpts -c copy -f dvd to fix timestamps
- Resolves "ERR: SCR moves backwards" error from dvdauthor
- FFmpeg direct encoding doesn't always create DVD-compliant streams
- Remux regenerates presentation timestamps correctly
Queue Animation Fix:
- Stop stripe animation on completed jobs
- Bug: Refresh() was always incrementing offset regardless of state
- Now only increments offset when animStop != nil (animation running)
- Completed/failed/cancelled jobs no longer show animated stripes
Testing:
- DVD authoring should now succeed on AVI files
- Completed queue jobs should show static progress bar
Improvements:
1. Track audio active state with atomic.Bool flag
2. Handle videos without audio track gracefully
- If audio fails to start, video plays at natural frame rate
- Clear error messages indicate "video-only playback"
3. Better A/V sync logging for debugging
- Log when video ahead/behind and actions taken
- Log good sync status periodically (every ~6 seconds at 30fps)
- More granular logging for different sync states
4. Proper cleanup when audio stream ends or fails
How it works:
- audioActive flag set to true when audio starts successfully
- Set to false when audio fails to start or ends
- Video checks audioActive before syncing to audio clock
- If no audio: video just paces at natural frame rate (no sync)
- If audio active: full A/V sync with adaptive timing
Expected improvements:
- Video-only files (GIFs, silent videos) play smoothly
- Better debugging info for sync quality
- Graceful degradation when audio missing
Priority 3 fix from PLAYER_PERFORMANCE_ISSUES.md - addresses the root
cause of A/V desync in player module.
Changes:
- Audio loop now tracks bytes written and updates master clock (audioTime)
- Audio clock calculation: bytesWritten / (sampleRate × channels × bytesPerSample)
- Video loop already syncs to audio master clock (from previous commit)
- Master clock updates happen after each audio chunk write
How it works:
- Audio is the timing master, plays at natural rate
- Video reads audio clock and adapts timing to stay in sync
- If video >3 frames behind: drop frame and resync
- If video >3 frames ahead: wait longer
- Otherwise: adjust sleep duration for gradual sync
Expected improvements:
- Rock-solid A/V sync maintained over extended playback
- No more drift between audio and video
- Adaptive recovery from temporary slowdowns
Combined with Priority 1 (larger audio buffers) and Priority 2 (FFmpeg
volume control), this completes the core A/V sync architecture.
- Current state: 3 modules partially/fully extracted
- upscale_module.go: showUpscaleView + AI helpers migrated successfully
- Build syntax: ✅ Clean
- Build failing due to unrelated Fyne API issue in internal/ui/queueview.go
- Ready for next incremental extraction steps
- Move showUpscaleView() from main.go to upscale_module.go
- Remove AI helper functions (detectAIUpscaleBackend, checkAIFaceEnhanceAvailable, etc.)
- Syntax passes, ready for further migration
- Build error is unrelated Fyne API issue in internal/ui
- main.go restored from corruption (13,664 lines)
- upscale_module.go created with AI helper functions
- Ready for safer incremental extraction approach
- Create thumb_module.go with showThumbView(), buildThumbView(), executeThumbJob()
- Remove showThumbView() from main.go
- buildThumbView() and executeThumbJob() still in main.go to be removed
- Syntax check passes
- Working on large function extraction
