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- spectool --wav <input.spec> <output.wav>: decodes .spec to mono 16-bit
WAV at 32 kHz using IDCT-OLA synthesis (no synthesis window).
The analysis Hann window at 50% overlap satisfies w[n]+w[n+H]=1,
so the synthesis window must be rectangular for perfect reconstruction.
- Add imdct_512 / imdct_fft to audio lib (fft.cc, fft.h, idct.cc, dct.h)
for future MDCT-based synthesis.
- test_wav_roundtrip: in-process OLA analyze+decode SNR test (≥30 dB).
Currently measures 53 dB on a 440 Hz sine.
- Fix stale test_spectool.cc: version assertion updated from 1 to
SPEC_VERSION_V2_OLA (was always wrong since OLA fix landed).
- Docs: TOOLS_REFERENCE.md removes dead specview, documents --wav /
--normalize / test_gen. HOWTO.md adds decode section. TRACKER.md
notes spec v2 OLA format and decode command.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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