NVENC ran CBR (bit_rate == max_bit_rate, rc=cbr) but never set rc_buffer_size,
so it used a loose default VBV. A high-motion P-frame was then allowed to spike
to many times the average frame size; the extra packets overflow the depth-2
send queue (newest frame dropped) and the kernel UDP buffer (WouldBlock drops),
which the client sees as framedrops/jitter — and on the infinite-GOP GameStream
path as old/stale frames flashing until the next RFI.
Set a tight ~1-frame VBV (rc_buffer_size = bitrate/fps) so the encoder holds
frame size roughly constant and absorbs motion as a momentary QP/quality dip
instead — the Sunshine/Moonlight low-latency model. Tunable via
PUNKTFUNK_VBV_FRAMES (default 1.0); larger trades burst tolerance for motion
quality. Fixes both the punktfunk/1 and GameStream paths (shared encoder).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
punktfunk-host builds unchanged against either FFmpeg 7.x (libavcodec 61) or 8.x
(libavcodec 62) — ffmpeg-sys-next auto-detects the system version, and the host's
ffmpeg FFI only touches long-stable APIs. Confirmed by building + running live on a
Bazzite F43 box (FFmpeg 7.1.3): full gamescope capture → zero-copy dmabuf→CUDA →
NVENC H.265 at 1280x720x60, p50 ~0.96 ms. Just doc/spec accuracy, no code change:
- encode/linux.rs + CLAUDE.md: drop the "FFmpeg 8 only" claim; note 7.x/8.x both work.
- rpm spec: add the missing zero-copy GPU build deps the link actually needs —
pkgconfig(gl) + pkgconfig(gbm) (mesa) — and document that -lcuda needs libcuda.so at
link time (NVIDIA host, or the CUDA toolkit stub on a headless COPR/koji builder).
Tracked for a proper fix: make the cuda/gbm/GL FFI dlopen-based like khronos-egl so
the RPM builds on a GPU-less host.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Full project rename, decided 2026-06-10:
- Crates/binaries: punktfunk-core / punktfunk-host / punktfunk-client-rs.
- C ABI: punktfunk_* symbols, Punktfunk* types, include/punktfunk_core.h,
PUNKTFUNK_FEATURE_QUIC guard (header regenerated; cbindgen renames updated, incl.
PUNKTFUNK_BTN_*/PUNKTFUNK_AXIS_* wire constants).
- Protocol: punktfunk/1 — control-plane magic LMN1 → PKF1, nonce salt lmn1 → pkf1.
WIRE BREAK: clients must be rebuilt from this revision.
- Env knobs: PUNKTFUNK_VIDEO_SOURCE / PUNKTFUNK_COMPOSITOR / PUNKTFUNK_ZEROCOPY / ….
- Host config dir: ~/.config/punktfunk (the box's dir was migrated in place — the
persistent identity is unchanged, pinned fingerprints stay valid).
- Swift package: PunktfunkKit + PunktfunkCore.xcframework + PunktfunkConnection
(Sources/PunktfunkClient app + tests renamed with it); build-xcframework.sh updated.
- scripts/: 60-punktfunk.rules, punktfunk-host.service; OpenAPI doc regenerated.
Also: scripts/headless/run-headless-kde.sh — full headless Plasma bringup. Root cause of
"desktop but no apps/settings" over the stream: plasmashell launched without
XDG_MENU_PREFIX=plasma-, so the launcher resolved a nonexistent applications.menu and
rendered an empty menu. The script sets the complete KDE session env (menu prefix,
KDE_FULL_SESSION, session version) and rebuilds ksycoca before starting plasmashell.
Gate: 97/97 tests, clippy -D warnings (both feature sets), fmt, C-ABI harness PASS,
zero lumen references left outside .git.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehler