GpuCompositor::upload converted f32 RGBA layers (effects rendered on the CPU, captions,
whole-frame fallbacks) and 16-bit YUV frames (ProRes render previews) to half floats on the UI
thread every time a frame was shown: 8.3 M values per 1080p RGBA layer, 4 M per ProRes frame.
filmcraft_gpu::prepare(plan) now does those conversions on the frame worker that built the plan
(parallel chunks; 16-bit codes through a cached per-bit-depth table) and the plan cache stores
them with the plan (frames::GpuPlan), bounded by count and bytes (1 GiB). composite_prepared()
only copies bytes into textures. The texels are bit-identical (new test compares the read-back
output of both paths for f32, 10-bit 4:2:2 and fallback-image plans).
bench, same-session A/B (GPU path, after-preview Full, 2 rounds, load avg 50–95):
UI-thread present time p50/p95: plays from previews 11–31 / 34–77 ms → 3.6–5.8 / 4–14 ms;
live effects play 17–28 / 31–56 ms → 4.1 / 12 ms (first run)
plays from previews: 184/8, 183/9, 189/3, 169/23 → 192/0, 192/0, 191/1, 192/0 shown/dropped
live effects play (CPU-bound, ~6 cores at this load): too noisy to compare (0–117 shown either way)
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
crates/golden (test-only, L3): nine procedural 320x180 scenes (transform
and opacity, blend modes, Gaussian Blur, Lumetri basic, Crop, Cross
Dissolve / Dip to Black / Wipe mid-transition, timecode/clip-name text)
rendered on the CPU and compared with committed goldens (PSNR >= 45 dB,
max <= 12, p99 <= 2); FILMCRAFT_BLESS=1 regenerates them with
attribution sidecars. testkit::golden adds PNG I/O, diff metrics and
failure images. The same scenes are composited on the GPU and compared
with the CPU.
GPU parity exposed a real bug: GpuCompositor cached uploads by
pixel-buffer address without owning the buffer, so a new frame
allocated at a freed frame's address was drawn with a stale texture
(whole wrong frames, PSNR ~12 dB). The cache now keeps the buffer
alive; regression test upload_cache_keeps_buffers_alive.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
