nx_jpeg_block_enc.nx

nx_jpeg_block_enc.nx -- SOVEREIGN JPEG baseline block entropy coder (J2). Encodes one 8x8 block's zigzag-ordered quantized coefficients into JPEG baseline entropy bits: DC as a difference from the previous block's DC (Huffman category + sign-magnitude), AC as run-length of zeros + (run,size) Huffman with ZRL (16-zero) runs and a trailing EOB. The matched decoder reverses it. Composes the audited pieces: nx_jpeg_huff_enc (J1 tables/emit/decode) over nx_h264_bitwriter. Patent-clean (JPEG/Annex K public since 1992). Self-proof = block encode->decode round-trip. license_tier: ORIGINAL