[PR #1876] fix(mp4/mkv): Add HEVC/H.265 caption extraction for MP4 and Matroska containers #2659

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claunia · 2026-01-29T17:23:17Z

claunia commented

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

Original Pull Request: https://github.com/CCExtractor/ccextractor/pull/1876

State: closed
Merged: Yes

Summary

Adds HEVC/H.265 caption extraction support for MP4 and MKV containers
Fixes issue where EIA-608/708 captions embedded in HEVC SEI NAL units weren't extracted
Key fix: Added store_hdcc() call to flush buffered CC data after each sample/frame

MP4 Changes (mp4.c)

Add HEVC subtype definitions (hev1, hvc1)
Add process_hevc_sample() to parse HEVC NAL units and extract CC
Add process_hevc_track() to iterate through HEVC track samples
Detect and process HEVC tracks in processmp4()

MKV Changes (matroska.c/h)

Add hevc_codec_id constant for V_MPEGH/ISO/HEVC
Add hevc_track_number field to track HEVC video tracks
Add process_hevc_frame_mkv() with HEVC-specific NAL parsing
Parse HEVCDecoderConfigurationRecord in codec private data
Route HEVC tracks through parse_simple_block()

Test plan

Build completes successfully
MP4 HEVC extraction: 73 captions extracted correctly
MKV HEVC extraction: 73 captions extracted correctly (matches MP4)
Run regression tests on sample platform

Closes #1690

🤖 Generated with Claude Code

**Original Pull Request:** https://github.com/CCExtractor/ccextractor/pull/1876 **State:** closed **Merged:** Yes --- ## Summary - Adds HEVC/H.265 caption extraction support for **MP4** and **MKV** containers - Fixes issue where EIA-608/708 captions embedded in HEVC SEI NAL units weren't extracted - Key fix: Added `store_hdcc()` call to flush buffered CC data after each sample/frame ### MP4 Changes (mp4.c) - Add HEVC subtype definitions (hev1, hvc1) - Add `process_hevc_sample()` to parse HEVC NAL units and extract CC - Add `process_hevc_track()` to iterate through HEVC track samples - Detect and process HEVC tracks in `processmp4()` ### MKV Changes (matroska.c/h) - Add `hevc_codec_id` constant for V_MPEGH/ISO/HEVC - Add `hevc_track_number` field to track HEVC video tracks - Add `process_hevc_frame_mkv()` with HEVC-specific NAL parsing - Parse HEVCDecoderConfigurationRecord in codec private data - Route HEVC tracks through `parse_simple_block()` ## Test plan - [x] Build completes successfully - [x] MP4 HEVC extraction: 73 captions extracted correctly - [x] MKV HEVC extraction: 73 captions extracted correctly (matches MP4) - [ ] Run regression tests on sample platform Closes #1690 🤖 Generated with [Claude Code](https://claude.com/claude-code)

claunia added the pull-request label 2026-01-29 17:23:18 +00:00

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Reference: starred/ccextractor#2659