Upstream sizes the raw quantized-payload worst-case buffer at
aligned_width*aligned_height*2 bytes: real headroom for 4:2:0's 1.5
samples/px, but half of what 4:4:4's 3 samples/px can produce. Busy 4:4:4
content overruns the buffer on the GPU and corrupts the adjacent meta/bucket
suballocations — nondeterministic corrupt bitstreams and encoder crashes at
ANY target bitrate (smooth content never trips it, which is why 4:2:0 and
simple 4:4:4 both look fine). Found by the Phase-0 measurement matrix for
design/pyrowave-444-hdr.md; fix validated alone via upstream's own devel
tools on the RTX 5070 Ti: deterministic byte-identical outputs across runs,
1080p + 4K, 8- and 16-bit, PSNR at the expected operating points.
Patch lives in crates/pyrowave-sys/patches/ and vendor-pyrowave.sh now
re-applies patches on re-vendor; PUNKTFUNK-VENDOR.txt records it. Upstream
report to follow. No wire/ABI change; 4:2:0 sizing unchanged.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Phase 0 of design/pyrowave-codec-plan.md — the opt-in wired-LAN ultra-low-
latency codec. Vendored at upstream 509e4f88 (API 0.4.0, Granite 44362775,
volk + vulkan-headers pins in PUNKTFUNK-VENDOR.txt), pruned to the 6.6 MB
the standalone no-renderer build needs; scripts/vendor-pyrowave.sh
reproduces the tree (a pin bump is protocol-affecting, plan §4.2).
build.rs drives the wrapper CMakeLists (static archives incl. a static
C-API lib upstream only ships shared) + bindgen over pyrowave.h; Linux and
Windows only, empty stub elsewhere (Apple gets a native Metal port, §4.7).
Offline-safe by construction: no network, no system lib, vendored Vulkan
headers — same model as the opus dep (flatpak builder has no network).
Phase-0 validation on .21 (RTX 5070 Ti, driver 610.43.03):
- upstream pyrowave-c-test + interop test (incl. dmabuf/DRM-modifier
Vulkan<->Vulkan) pass, from the pristine AND the pruned tree
- GPU kernel times at ~1.6 bpp noise: encode/decode 0.090/0.042 ms @800p,
0.146/0.067 @1080p, 0.226/0.103 @1440p, 0.477/0.201 @4K — order of
magnitude under NVENC's 1-2 ms retrieve, CBR lands within ~100 B of
target
- cargo test -p pyrowave-sys green (static link + API-version pin check)
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
enricobuehler