Clean up VCL HRD TODO comment in avc_functions.c

[Harshdhall01]

[IMPROVEMENT] Clean up VCL HRD TODO comment in avc_functions.c

Addresses #1894

Summary

Replace unclear TODO with explanation of why VCL HRD parameters are skipped. VCL HRD is for video buffering compliance and not needed for caption extraction.

Changes:

• Replace TODO comment with clear explanation
• Update mprint message to be more informative
• Remove commented-out exit(1)

Context:

This code handles VCL (Video Coding Layer) HRD parameters in H.264/AVC streams. These parameters are for video decoder buffering compliance and are not needed for CCExtractor's purpose of extracting closed captions from SEI NAL units.

The existing code correctly skips these parameters - this PR just improves the code documentation to make that clear.

Testing:

• ✅ Code changes reviewed (comments and log message only)
• ✅ No functional/logic changes
• ⚠️ Local build not tested (requires Visual Studio C++ Build Tools on Windows)
• CI will verify compilation

Thanks to @cfsmp3 for the detailed guidance on this cleanup!

---

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Note: CHANGES.TXT not updated as this is a minor documentation-only change with no functional impact.

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[cfsmp3]

Thank you for this cleanup! The change looks good - improving documentation and removing the commented-out exit(1) is helpful.

However, the CI format check is failing. Please fix:

1. Line 907: The second comment line has spaces + tabs instead of consistent tabs
2. Line 910: Remove the trailing whitespace on the empty line

You can run clang-format -i src/lib_ccx/avc_functions.c locally or just fix the indentation on those two lines.

Once fixed, this is ready to merge.

[Harshdhall01]

Thank you for this cleanup! The change looks good - improving documentation and removing the commented-out exit(1) is helpful.

However, the CI format check is failing. Please fix:

1. Line 907: The second comment line has spaces + tabs instead of consistent tabs
2. Line 910: Remove the trailing whitespace on the empty line

You can run clang-format -i src/lib_ccx/avc_functions.c locally or just fix the indentation on those two lines.

Once fixed, this is ready to merge.

@cfsmp3 Thank you for the quick review and clear feedback!

I've fixed both formatting issues:

• Line 908: Changed from mixed spaces+tabs to consistent tab indentation
• Line 911: Removed trailing whitespace on the empty line

The format check should pass now. Ready for another look when you have time!

[Harshdhall01]

I've removed the extra blank line. The format check should pass now!

[ccextractor-bot]

CCExtractor CI platform finished running the test files on linux. Below is a summary of the test results, when compared to test for commit fd15528...:

Report Name	Tests Passed
Broken	13/13
CEA-708	14/14
DVB	7/7
DVD	3/3
DVR-MS	2/2
General	27/27
Hardsubx	1/1
Hauppage	3/3
MP4	3/3
NoCC	10/10
Options	86/86
Teletext	21/21
WTV	13/13
XDS	34/34

Congratulations: Merging this PR would fix the following tests:

• ccextractor --autoprogram --out=ttxt --latin1 --ucla dab1c1bd65..., Last passed: Never
• ccextractor --out=srt --latin1 --autoprogram 29e5ffd34b..., Last passed: Never
• ccextractor --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9..., Last passed: Never
• ccextractor --startcreditsnotbefore 1 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9..., Last passed: Never
• ccextractor --startcreditsnotafter 2 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9..., Last passed: Never
• ccextractor --startcreditsforatleast 1 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9..., Last passed: Never
• ccextractor --startcreditsforatmost 2 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9..., Last passed: Never

All tests passed completely.

Check the result page for more info.

[ccextractor-bot]

CCExtractor CI platform finished running the test files on windows. Below is a summary of the test results, when compared to test for commit fd15528...:

Report Name	Tests Passed
Broken	13/13
CEA-708	14/14
DVB	7/7
DVD	3/3
DVR-MS	2/2
General	27/27
Hardsubx	1/1
Hauppage	3/3
MP4	3/3
NoCC	10/10
Options	86/86
Teletext	21/21
WTV	13/13
XDS	34/34

Congratulations: Merging this PR would fix the following tests:

• ccextractor --autoprogram --out=srt --latin1 --quant 0 85271be4d2..., Last passed: Never
• ccextractor --autoprogram --out=ttxt --latin1 --ucla dab1c1bd65..., Last passed: Never
• ccextractor --out=srt --latin1 --autoprogram 29e5ffd34b..., Last passed: Never
• ccextractor --out=spupng c83f765c66..., Last passed: Never
• ccextractor --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9..., Last passed: Never
• ccextractor --startcreditsnotbefore 1 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9..., Last passed: Never
• ccextractor --startcreditsnotafter 2 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9..., Last passed: Never
• ccextractor --startcreditsforatleast 1 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9..., Last passed: Never
• ccextractor --startcreditsforatmost 2 --startcreditstext "CCextractor Start crdit Testing" c4dd893cb9..., Last passed: Never

All tests passed completely.

Check the result page for more info.