feat(clients): unified stats vocabulary across every client + Moonlight comparison docs

One stat model everywhere (design/stats-unification.md): four measurement
points (capture/received/decoded/displayed), three stages that tile the
interval exactly, and a HUD that shows the addition explicitly —

  end-to-end 14.2 ms p50 · 19.8 p95 · capture→on-glass
  = host+network 9.8 + decode 2.1 + display 2.3

replacing each client's ad-hoc mix of overlapping absolutes (the Apple HUD's
three arrow lines that looked sequential but weren't), mean-vs-median decode
times (Windows/Linux), missing same-host-clock flags (Windows/Linux), and
three different names for the same capture→received measurement (probe's
"reassembled", Apple/Android's "client", Windows/Linux's post-decode "lat").

Per client: Apple threads receivedNs through the VT decode via the frame
refcon bit pattern so the decode stage exists at all (stage-1 fallback
honestly degrades to a capture→received headline); Windows carries
FrameTimes through the existing frame channel to the render thread and adds
e2e p50/p95 post-Present; Linux stamps received at AU pop and rides
decoded_ns on DecodedFrame to the paintable-set site; Android pairs receipt
stamps with MediaCodec output buffers via the codec's pts round-trip (JNI
stats array 14→16 doubles, indexes 0-13 unchanged). fps now uniformly counts
received AUs; lost/(received+lost) per window, hidden at zero.

docs-site gains "Understanding the Stats Overlay": what each line means, why
the equation only approximately sums (percentiles), and a line-by-line
Moonlight/Sunshine matrix — including that Moonlight has no end-to-end
number and its "network latency" is an ENet control RTT, so punktfunk's
headline must not be compared against any single Moonlight line.

Verified here: linux client + probe + core check/clippy/fmt green, android
native cargo-ndk arm64 check green. Pending: Windows CI + on-glass, swift
test on the mac, on-device Android.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
2026-07-03 21:01:29 +00:00
parent c7630ff5dc
commit 09a5957c6d
38 changed files with 1122 additions and 380 deletions
+78 -8
View File
@@ -9,16 +9,22 @@
use ndk::data_space::DataSpace;
use ndk::media::media_codec::{
DequeuedInputBufferResult, DequeuedOutputBufferInfoResult, MediaCodec, MediaCodecDirection,
OutputBuffer,
};
use ndk::media::media_format::MediaFormat;
use ndk::native_window::{FrameRateCompatibility, NativeWindow};
use punktfunk_core::client::NativeClient;
use punktfunk_core::error::PunktfunkError;
use punktfunk_core::session::Frame;
use std::collections::VecDeque;
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::Arc;
use std::time::{Duration, Instant};
/// Cap on the pts→received-timestamp map below: MediaCodec holds only a handful of frames in
/// flight, so anything beyond this is stale (codec flushed / HUD toggled) and gets evicted.
const IN_FLIGHT_CAP: usize = 64;
/// The decode loop. Runs on the `pf-decode` thread until `shutdown` is set or the session closes.
pub fn run(
client: Arc<NativeClient>,
@@ -141,9 +147,14 @@ pub fn run(
// climbs.
let mut last_dropped = client.frames_dropped();
let mut last_kf_req: Option<Instant> = None;
// Capture→client-receipt latency uses the negotiated host-minus-client clock offset (0 if the
// host didn't answer the skew handshake — then the HUD flags it "same-host").
// Skew-corrected latency stats (spec: design/stats-unification.md) use the negotiated
// host-minus-client clock offset (0 if the host didn't answer the skew handshake — then the
// HUD flags it "(same-host clock)").
let clock_offset = client.clock_offset_ns;
// HUD stage split: receipt timestamps keyed by the pts we queue into the codec, so the decoded
// point (output-buffer dequeue — MediaCodec round-trips presentationTimeUs) can be paired back
// to its receipt for the `decode` stage. Only fed while the HUD is visible.
let mut in_flight: VecDeque<(u64, i128)> = VecDeque::new();
// The dataspace we've signalled on the Surface so far (None = default/SDR). Set reactively once
// the decoder reports an HDR stream (see `drain`); avoids re-applying every format event.
let mut applied_ds: Option<DataSpace> = None;
@@ -164,15 +175,21 @@ pub fn run(
&p[..p.len().min(6)]
);
}
// HUD stat: capture→client-receipt latency = client_now + (hostclient)
// HUD stat, `received` point: host+network = client_now + (hostclient)
// capture_pts. Gated on the HUD being visible — `enabled` first so the hidden
// steady state skips the wall-clock read and the lock entirely.
// steady state skips the wall-clock read and the lock entirely. The receipt
// stamp is also parked in `in_flight` (keyed by the pts the codec will echo on
// the output buffer) for the decoded-point pairing in `drain`.
if stats.enabled() {
let lat_ns =
now_realtime_ns() + clock_offset as i128 - frame.pts_ns as i128;
let received_ns = now_realtime_ns();
let lat_ns = received_ns + clock_offset as i128 - frame.pts_ns as i128;
let lat_us = (lat_ns > 0 && lat_ns < 10_000_000_000)
.then_some((lat_ns / 1000) as u64);
stats.note(frame.data.len(), lat_us, clock_offset != 0);
stats.note_received(frame.data.len(), lat_us, clock_offset != 0);
in_flight.push_back((frame.pts_ns / 1000, received_ns));
if in_flight.len() > IN_FLIGHT_CAP {
in_flight.pop_front(); // stale — codec never echoed it back
}
}
pending = Some(frame);
}
@@ -202,7 +219,15 @@ pub fn run(
} else {
Duration::ZERO
};
let (r, d) = drain(&codec, &window, &mut applied_ds, wait);
let (r, d) = drain(
&codec,
&window,
&mut applied_ds,
wait,
&stats,
&mut in_flight,
clock_offset,
);
rendered += r;
discarded += d;
@@ -330,11 +355,19 @@ fn feed(codec: &MediaCodec, au: &[u8], pts_us: u64) -> bool {
/// the caller's input is blocked so the loop waits on decoder progress instead of busy-spinning.
/// Returns `(rendered, discarded)`. Also reacts to `OutputFormatChanged` (which can interleave
/// between buffers — handled without losing the held buffer) to signal HDR on the Surface.
///
/// Each dequeued buffer is also the HUD's `decoded` measurement point (rendered or not — the frame
/// finished decoding either way): end-to-end = decoded + clock_offset capture pts, and the
/// `decode` stage pairs the buffer's echoed presentationTimeUs back to the receipt stamp in
/// `in_flight` (single-clock local difference, no skew involved).
fn drain(
codec: &MediaCodec,
window: &NativeWindow,
applied_ds: &mut Option<DataSpace>,
first_wait: Duration,
stats: &crate::stats::VideoStats,
in_flight: &mut VecDeque<(u64, i128)>,
clock_offset: i64,
) -> (u64, u64) {
let mut held = None; // newest ready buffer so far, presented after the loop
let mut discarded: u64 = 0;
@@ -343,6 +376,9 @@ fn drain(
match codec.dequeue_output_buffer(wait) {
Ok(DequeuedOutputBufferInfoResult::Buffer(buf)) => {
wait = Duration::ZERO; // only the first dequeue may block
if stats.enabled() {
note_decoded(stats, in_flight, clock_offset, &buf);
}
if let Some(stale) = held.replace(buf) {
// A newer frame is ready — drop the held one without rendering.
if let Err(e) = codec.release_output_buffer(stale, false) {
@@ -392,6 +428,40 @@ fn drain(
(rendered, discarded)
}
/// HUD `decoded` point for one dequeued output buffer: build the end-to-end (capture→decoded,
/// skew-corrected, clamped to (0, 10 s)) and `decode` (received→decoded, single-clock local, ≥ 0)
/// samples and hand them to [`crate::stats::VideoStats::note_decoded`]. The codec echoes the input
/// `presentationTimeUs` on the output buffer, which keys the receipt stamp in `in_flight`; entries
/// older than the echoed pts are evicted (decode order == input order here — low-latency, no
/// B-frames — so anything before it was dropped inside the codec or stamped before a flush).
fn note_decoded(
stats: &crate::stats::VideoStats,
in_flight: &mut VecDeque<(u64, i128)>,
clock_offset: i64,
buf: &OutputBuffer<'_>,
) {
let pts_us = buf.info().presentation_time_us().max(0) as u64;
let decoded_ns = now_realtime_ns();
// Pair the echoed pts back to its receipt stamp, evicting stale (older) entries as we go.
let mut received_ns = None;
while let Some(&(p, r)) = in_flight.front() {
if p > pts_us {
break; // future frame — leave it for its own output buffer
}
in_flight.pop_front();
if p == pts_us {
received_ns = Some(r);
break;
}
}
// pts_us is the truncated frame.pts_ns/1000 we queued, so ×1000 re-approximates capture time
// to < 1 µs — negligible against the ms-scale figures shown.
let e2e_ns = decoded_ns + clock_offset as i128 - pts_us as i128 * 1000;
let e2e_us = (e2e_ns > 0 && e2e_ns < 10_000_000_000).then_some((e2e_ns / 1000) as u64);
let decode_us = received_ns.map(|r| ((decoded_ns - r).max(0) / 1000) as u64);
stats.note_decoded(e2e_us, decode_us);
}
/// Map the decoder's reported output colour to a BT.2020 HDR dataspace, or `None` for SDR. The
/// integer values are the Android MediaFormat colour constants the NDK shares: COLOR_TRANSFER
/// ST2084 = 6 (PQ/HDR10), HLG = 7; COLOR_RANGE FULL = 1, LIMITED = 2 (the host encodes limited).