nx_flac.nx

nx_flac.nx -- FLAC lossless audio decoder core. The audio quadrant of this tree held PCM and nothing else. FLAC is the cheapest real codec to close that with: it is native in every browser, it is the archival lossless standard, and its whole decode path is integer arithmetic -- no transform, no float, no psychoacoustics. FLAC is MSB-first (unlike DEFLATE/VP8L), so this composes onto nx_bitstream_read_msb. Its residuals are Rice-coded, which nx_huffman.nx already names as a sibling of its own family. THE SIGN TRAP. Rice codes an unsigned value that must be UNFOLDED to signed by zigzag: even -> +n/2, odd -> -(n+1)/2. Getting that backwards produces audio that decodes without error and sounds like noise, because every residual has the wrong sign but the right magnitude. There is no checksum on the sample path that would catch it -- only the frame CRC, which many decoders skip. genealogy_id: flac_format_spec lineage_id: nx_flac_v1 license_tier: ORIGINAL