j2k-transcode-metal

Metal acceleration adapter for J2K JPEG-to-J2K/HTJ2K transcode stages on macOS.

This crate accelerates supported transform stages and delegates runtime setup to j2k-metal-support.

High-level route-report example:

cargo run -p j2k-transcode-metal --example jpeg_to_htj2k_route_report

The example prints the requested backend, selected transform backend, final codestream output backend, structured Auto fallback reason, transfer bytes, and the transcode pipeline residency map.

On macOS, resident_codestream_buffer_from_metal_encoded_j2k converts buffer-backed j2k-metal encode output into the shared ResidentCodestreamBuffer handoff descriptor with allocation and capacity validation.