[PR #1919] feat(matroska): Add VOBSUB subtitle extraction support for MKV files #2715

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claunia · 2026-01-29T17:23:33Z

claunia commented

2026-01-29 17:23:33 +00:00

Original Pull Request: https://github.com/CCExtractor/ccextractor/pull/1919

State: closed
Merged: Yes

Summary

Adds full VOBSUB (S_VOBSUB) subtitle extraction support for Matroska files
Previously CCExtractor would just print "Error: VOBSUB not supported" and produce empty files
Now generates proper .idx and .sub file pairs that work with VLC, FFmpeg, and other players
Includes documentation and Docker tooling for OCR conversion to SRT

Changes

Core VOBSUB extraction (src/lib_ccx/matroska.c):

Added PS Pack header generation with SCR derived from timestamps
Added PES header generation with PTS for subtitle timing
Added save_vobsub_track() function to write both .idx and .sub files
Added hex format specifier (LLX_M) for cross-platform file position formatting
Standard 2048-byte block alignment for proper VOBSUB format

Documentation and tooling:

Added docs/VOBSUB.md - comprehensive guide for VOBSUB extraction and OCR conversion
Added tools/vobsubocr/Dockerfile - Docker image for subtile-ocr (VOBSUB to SRT conversion)

Usage

# Extract VOBSUB from MKV
ccextractor movie.mkv
# Output: movie_eng.idx + movie_eng.sub

# Convert to SRT (using Docker)
docker build -t subtile-ocr tools/vobsubocr/
docker run --rm -v $(pwd):/data subtile-ocr -l eng -o /data/movie.srt /data/movie_eng.idx

Test plan

Tested with sample #178 from issue (bugs.mkv with VOBSUB tracks)
Output validates with FFprobe as dvd_subtitle codec
Timestamps match reference extraction (mkvextract)
File positions match reference extraction
SPU data is identical to reference extraction
OCR with subtile-ocr produces identical SRT to mkvextract reference

Fixes #1371

🤖 Generated with Claude Code

**Original Pull Request:** https://github.com/CCExtractor/ccextractor/pull/1919 **State:** closed **Merged:** Yes --- ## Summary - Adds full VOBSUB (S_VOBSUB) subtitle extraction support for Matroska files - Previously CCExtractor would just print "Error: VOBSUB not supported" and produce empty files - Now generates proper .idx and .sub file pairs that work with VLC, FFmpeg, and other players - Includes documentation and Docker tooling for OCR conversion to SRT ## Changes **Core VOBSUB extraction (`src/lib_ccx/matroska.c`):** - Added PS Pack header generation with SCR derived from timestamps - Added PES header generation with PTS for subtitle timing - Added `save_vobsub_track()` function to write both .idx and .sub files - Added hex format specifier (`LLX_M`) for cross-platform file position formatting - Standard 2048-byte block alignment for proper VOBSUB format **Documentation and tooling:** - Added `docs/VOBSUB.md` - comprehensive guide for VOBSUB extraction and OCR conversion - Added `tools/vobsubocr/Dockerfile` - Docker image for subtile-ocr (VOBSUB to SRT conversion) ## Usage ```bash # Extract VOBSUB from MKV ccextractor movie.mkv # Output: movie_eng.idx + movie_eng.sub # Convert to SRT (using Docker) docker build -t subtile-ocr tools/vobsubocr/ docker run --rm -v $(pwd):/data subtile-ocr -l eng -o /data/movie.srt /data/movie_eng.idx ``` ## Test plan - [x] Tested with sample #178 from issue (bugs.mkv with VOBSUB tracks) - [x] Output validates with FFprobe as `dvd_subtitle` codec - [x] Timestamps match reference extraction (mkvextract) - [x] File positions match reference extraction - [x] SPU data is identical to reference extraction - [x] OCR with subtile-ocr produces identical SRT to mkvextract reference Fixes #1371 🤖 Generated with [Claude Code](https://claude.com/claude-code)

claunia added the pull-request label 2026-01-29 17:23:33 +00:00

claunia closed this issue

2026-01-29 17:23:34 +00:00

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Reference: starred/ccextractor#2715