perf(dvb): Lazy OCR initialization for DVB subtitle decoder #1943
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Previously, Tesseract OCR was initialized eagerly when a DVB subtitle stream was detected in the transport stream. This caused ~10 second startup overhead even for files that: - Have DVB streams but no actual bitmap subtitles - Have DVB streams alongside CEA-608 text captions (which don't need OCR) - Have DVB streams but the user only wants raw bitmap output The initialization also created OpenMP worker threads that generated hundreds of thousands of futex syscalls, causing valgrind tests to take 15+ minutes instead of seconds. This change defers OCR initialization until a DVB bitmap region actually needs to be processed with OCR. Benefits: - Files with DVB streams but no bitmap content: 10s → 0.1s - Files with DVB + CEA-608 captions: 10s → 1-3s - Valgrind test performance: 15+ min → seconds (no thread pool overhead when OCR isn't used) The ocr_initialized flag ensures init_ocr() is called only once, on first bitmap encounter. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>
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CCExtractor CI platform finished running the test files on linux. Below is a summary of the test results, when compared to test for commit b23866f...:
Your PR breaks these cases:
Congratulations: Merging this PR would fix the following tests:
It seems that not all tests were passed completely. This is an indication that the output of some files is not as expected (but might be according to you). Check the result page for more info. |
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CCExtractor CI platform finished running the test files on windows. Below is a summary of the test results, when compared to test for commit b23866f...:
Your PR breaks these cases:
It seems that not all tests were passed completely. This is an indication that the output of some files is not as expected (but might be according to you). Check the result page for more info. |
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Summary
Problem
Previously, OCR was initialized eagerly in
dvbsub_init_decoder()whenever a DVB subtitle stream was detected. This caused performance issues:Solution
Move
init_ocr()call fromdvbsub_init_decoder()to the first actual OCR usage point indvbsub_decode_region_segment(). Anocr_initializedflag ensures single initialization.Performance Results
Test plan
🤖 Generated with Claude Code