atracdenc/src/atrac/at3/atrac3_bitstream.cpp, branch fix_input_file_pathOpenSource ATRAC1 ATRAC3 Encoderhttps://code.mastervirt.ru/atracdenc/atom?h=fix_input_file_path2026-04-19T22:27:45Zatrac3: reimplement tonal encoding. Use flatness-based tonal extraction2026-04-19T22:27:45ZDaniil Cherednikdan.cherednik@gmail.com2026-04-18T14:51:23Zurn:sha1:e784b79cfef682059cf5cc8cf9bed635e714c439
- Add shared CalcSpectralFlatnessPerBfu helper in atrac_psy_common
with BFU-table mapping.
- Implement ATRAC3 tonal extraction: compute MDCT energy, estimate
per-BFU flatness, extract up to 5-bin strongest tonal run in
low-flatness BFUs, and zero extracted bins in residual.
- Map extracted tonal bins into TTonalBlocks and integrate them into
bitstream coding.
- Update ATRAC3 bit allocation - reduce residual bits for BFUs with tonal
blocks, and increase tonal quantizer selection.
- Restore --notonal CLI option in main.cpp for A/B comparison.
[AT3] refactor bitstream allocation loop to bs_encode2026-04-11T21:20:06ZDaniil Cherednikdan.cherednik@gmail.com2026-04-11T21:18:36Zurn:sha1:a958b27a43f0a436406dc51b942ca2f3a417e7a7atrac3: ratio-scored transients, per-band gain boost, pre-echo reduction2026-03-15T20:13:24ZDaniil Cherednikdan.cherednik@gmail.com2026-03-15T20:13:24Zurn:sha1:34aee45f701cd49824a83cc3781b0c12976eca2f
Rewrites the ATRAC3 gain control pipeline to eliminate noise flashes
and substantially reduce pre-echo artifacts:
Transient detection & curve building (transient_detector.cpp/h):
- Replace legacy heuristic detector with ratio-scored DetectTransients:
score = peak/floor for rising (c/a) or falling (a/c) triplets, scored
and ranked, top-N kept, sorted by location
- Add explicit point0 derived from windowed-RMS match between bufCur and
the curve-modulated bufNext (CalcWindowedRmsAfterCurve)
- Replace RegionMax with RegionRMS for smoother region amplitude estimate
- Add per-band detection thresholds kMinScorePerBand[4] = {1.9,1.9,2.1,2.2}
- Dynamic minScore: scale threshold by min(1.5, max(1.0, overlapRatio)) to
suppress false-positive curves when previous frame dominates
- Scale constraint: curve[0].Level >= 3 to cap cross-frame amplification at 2x
Bit allocation (atrac3_bitstream.cpp/h):
- Add GainBoostPerBand[NumQMF] to TSingleChannelElement, computed in
CreateSubbandInfo and applied in CalcBitsAllocation
- levelBoost: compensate for Demodulate's GainLevel[minLevel] attenuation
- scaleBoost: compensate for next-frame cross-frame scale via lookahead
- Both capped (kLevelBoostCap=1, kScaleBoostCap=2) to avoid bit starvation
Upsampler (atrac3denc.cpp):
- Raise cutoff from 600 Hz to 800 Hz for tighter band separation
Tests (gain_processor_ut.cpp):
- Relax fixed curve shape assertions to ExpectCurveReasonable (bounds checks)
- Relax quantization error bound for dense-event spacing (<=128 samples)
Results (branch new_psy vs original baseline):
riddler: pre-echo worse 43->15/479 frames, 0 flashes
spine: pre-echo worse 192->107/1804 frames, 0 flashes
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Fix energy calculation for quantization units2025-09-05T20:08:03ZDaniil Cherednikdan.cherednik@gmail.com2025-08-23T19:59:46Zurn:sha1:65b8ae4337ad68ae0c10f609a11e77d96e5ad8e2Move implementation details into corresponding dirs (#52)2025-07-22T20:54:21ZDaniil Cherednikdan.cherednik@gmail.com2025-07-22T20:54:21Zurn:sha1:61045345fa43e54fb4fc3eee0e05b25451af9ca5