The spectra of the odd QMF bands are stored reversed. 8722c6f2bb
moved that reversal out of IMLT() and into the decoding of the
coefficients, but did it within each scale factor band, one place
off, and not at all for tonal components. The odd bands, which is
5.5 to 11 kHz and above 16.5 kHz at 44.1 kHz, have been decoded
wrongly since: against ffmpeg's decode that range was uncorrelated.
Reverse the whole band in IMLT() again, as ffmpeg does. The old
commit measured the saving it is giving up as 0.11 MHz on PP5024.
Checked with perfsim (Sansa e200v1 build) against ffmpeg's decode
of an OMA file and six RM files: the coherence of the 5.7 to 10.7
kHz range goes from under 0.01 to 0.99, the same as other bands.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
1bae7e0e0a