From 2f8926f433248af28081497e8371e02abe61d6ff Mon Sep 17 00:00:00 2001 From: skal Date: Thu, 5 Mar 2026 21:50:53 +0100 Subject: feat(spectool): add --wav decode, IMDCT, and roundtrip test MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - spectool --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 --- src/tests/gpu/test_spectool.cc | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'src/tests/gpu/test_spectool.cc') diff --git a/src/tests/gpu/test_spectool.cc b/src/tests/gpu/test_spectool.cc index 984322a..b90d236 100644 --- a/src/tests/gpu/test_spectool.cc +++ b/src/tests/gpu/test_spectool.cc @@ -3,6 +3,7 @@ // Generates a test WAV, analyzes it, and verifies the resulting .spec file. #include "audio/audio.h" +#include "audio/synth.h" #include #include #include @@ -54,7 +55,7 @@ int main() { size_t read = fread(&header, sizeof(SpecHeader), 1, f); assert(read == 1); assert(strncmp(header.magic, "SPEC", 4) == 0); - assert(header.version == 1); + assert(header.version == SPEC_VERSION_V2_OLA); assert(header.dct_size == 512); assert(header.num_frames > 0); -- cgit v1.2.3