Add tools/build_reference_decoders.sh: fetches and builds the open MPEG/3GPP
reference codecs that act as the sink decoders for the volumetric and
immersive-audio rows of the carriage demo, each pinned to a verified ref:
- G-PCC mpeg-pcc-tmc13 release-v23.0-rc2 -> tmc3
- V-PCC mpeg-pcc-tmc2 release-v25.0 -> PccApp{Encoder,Parser,...}
- IVAS 3GPP ivas-codec main @ 3882460 -> IVAS_cod / IVAS_dec
It handles the cmake 4.x policy override the MPEG trees need (their build.sh
rejects cmake major != 3), is idempotent (skips already-built trees), and
prints the exact PATH/TMC2_CFG export line to run wai_carriage_demo.sh. So the
real+decode / real+parse rows reproduce from a clean checkout instead of the
ad-hoc /tmp builds.
- demo header + registry: cross-reference the build script.
- .gitignore: ignore the script's default ./.reference-tools prefix.
Verified: refs resolve on all three remotes; the printed exports drive the
demo to 5 real+decode + 1 real+parse rows, all byte-exact.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
cf4c7bb8bd