feat(processor): implement adaptive crest factor compression for quiet recordings

[flexiondotorg]

Summary

Implement Strategy 2: Adaptive Crest Factor Compression - LUFS High-Crest Override. Detects very quiet recordings with high peak-to-average energy ratios and applies specialised LA-2A compression parameters to prevent distortion and improve clarity.

Changes

• Add high-crest override diagnostic fields (HighCrestDetected, HighCrestAttackMs, HighCrestReleaseMs) to LA-2A tuning reports
• Implement applyHighCrestOverrides() detection logic: identifies recordings where LUFS < -10 dB and crest factor > 8, triggering adaptive parameter adjustment
• Wire high-crest system into tuneLA2ACompressor() and sub-tuners (fixed, gentle, moderate, aggressive) with phase-specific parameter scaling
• Add 449 lines of unit and integration tests covering all crest factor scenarios
• Fix LUFS truncation bug by removing math.Round() call, preserving precision for very quiet recordings
• Update design documentation and README with high-crest strategy explanation and diagnostic reporting

Testing

• Unit tests: 100% coverage of crest factor detection thresholds and parameter calculations across all sub-tuner configurations
• Integration tests: verify wiring in full tuning pipeline, confirm diagnostic reporting in output
• All tests pass; golangci-lint clean

[cubic-dev-ai]

4 issues found across 8 files

Confidence score: 4/5

• Overall risk looks low because the issues are confined to diagnostics, tests, and documentation rather than core processing logic.
• Most significant functional concern is in internal/logging/report.go, where hardcoded NormTargetLUFS could make high-crest diagnostics diverge from configured loudnorm settings.
• Test and docs mismatches reduce confidence in validation and guidance but are not likely to affect runtime behavior directly (internal/processor/adaptive_test.go, README.md, docs/FilterCompressor-Teletronix LA-2A.md).
• Pay close attention to internal/logging/report.go, internal/processor/adaptive_test.go, README.md, docs/FilterCompressor-Teletronix LA-2A.md - diagnostics accuracy, test coverage, and documentation consistency.

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="internal/logging/report.go">

<violation number="1" location="internal/logging/report.go:856">
P2: Use `cfg.LoudnormTargetI` instead of hardcoding `NormTargetLUFS` in the high-crest diagnostics, otherwise the reported gain and projected TP drift from the actual loudnorm settings.</violation>
</file>

<file name="README.md">

<violation number="1" location="README.md:171">
P2: These added diagnostics don't match the surrounding example values, so the README now documents an impossible high-crest result for this sample.</violation>
</file>

<file name="internal/processor/adaptive_test.go">

<violation number="1" location="internal/processor/adaptive_test.go:2478">
P2: This test re-runs the same code path twice, so it cannot prove inactive recordings still match the pre-override tuner behaviour.</violation>
</file>

<file name="docs/FilterCompressor-Teletronix LA-2A.md">

<violation number="1" location="docs/FilterCompressor-Teletronix LA-2A.md:70">
P3: This adds 350 ms / 6.0 high-crest values, but the config table below still says `LA2ARelease` tops out at 300 ms and `LA2AKnee` at 5.0.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

0 issues found across 2 files (changes from recent commits).

_{Requires human review: Auto-approval blocked by 2 unresolved issues from previous reviews.}