g2flash/demos/video-bench.ts at main · hmmhmmhm/g2flash

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#!/usr/bin/env bun

// Stream a video (GIF) to the lens as fast as it acks, and benchmark byte count

// + framerate. Decodes/rescales/grayscales/compresses ALL frames up front, then

// sends them in order, pacing only on the per-fragment acks.

// Each frame is zlib-compressed and sent with a leading mode byte that selects

// a CFW display path. The 4bpp modes that go through the firmware's shadow (3 and

// 6) run their pixels through RLE before deflate — their payload is zlib(rle(px)),

// not zlib(px) — since runs of one gray level are what this content is made of.

// G2_MODE picks the encoding:

// delta (default) 4bpp: mode-6 keyframe, then mode-3 bounding-box updates

// raw4 4bpp: every frame -> mode 6 (headerless packed shadow)

// lz4 4bpp: STOCK 2.2.6.10 path — 4bpp BMP, LZ4'd, CompressMode=2

// The custom modes use the fixed 640x480 full-panel shadow while their EvenHub

// carrier remains 576x288. `raw4` sends that shadow in full; `delta` sends only

// the bounding box that changed after its initial keyframe.

// `delta` sends only the bounding box of pixels that changed vs the previous

// frame (as 4bpp), so for mostly-static content like Bad Apple it moves very few

// pixels per frame — the cheapest mode both on wire and on-device CPU, at the

// cost of one full keyframe up front (and every G2_KEYFRAME_INTERVAL frames).

// `lz4` is the odd one out: it is the only mode that needs NO custom firmware. Stock

// 2.2.6.10 added Even's own image compression (CompressMode 1=RLE, 2=LZ4), so this mode

// sends a plain 4bpp BMP compressed as an LZ4 *block* with CompressMode=2 and no leading

// mode byte, which the stock firmware inflates in evenhub_ui_reflash_event_handler and

// feeds to its normal BMP path. It exists to benchmark Even's official compression

// against ours on the same content. Notes: the firmware decompresses into a malloc(W*H)

// buffer sized from the container, so the payload must inflate to <= W*H bytes; and a

// CompressMode the firmware doesn't know is silently "treated as raw" (i.e. garbage on

// the lens) rather than rejected, so this mode is only meaningful against a 2.2.6.10+

// base. See notes/fw-2.2.6.10-lz4-images.md.

// bun video-bench.ts path/to/bad_apple.gif

// Make a GIF from any video with ffmpeg, e.g.:

// ffmpeg -i bad_apple.mp4 -vf "fps=30,scale=288:144:flags=area,format=gray" bad_apple.gif

// Env:

// G2_IMG_W / G2_IMG_H target size (custom modes require 640x480)

// G2_IMG_THRESHOLD >=0 = 1-bit threshold; -1 = grayscale (default -1)

// G2_MAX_FRAMES cap frame count (default 0 = all)

// G2_FRAME_STRIDE use every Nth decoded frame (default 1)

// G2_KEYFRAME_INTERVAL (delta mode) force a full frame every N (default 0 = only the first)

// G2_MODE "delta" (default), "raw4", or "lz4" (see above)

// G2_DRY_RUN=1 decode+compress+report only, don't connect/stream

// G2_MEASURE_PERSIST=1 also report frame sizes if zlib state persisted across

// frames (measurement only; firmware doesn't do this yet)

// G2_WINDOW pipelined image messages in flight at once (default 2; 1 = serial)

// G2_IMAGE_ARM lens the image data is written to: "R" (default) or "L". Only the

// image-raw writes move; session setup (prelude, create, rebuild) and

// the heartbeat always go to R, and the ack for an image message comes

// back on R either way (the arms sync internally), so an L-arm send is

// a write on L with its ack awaited on R.

// About G2_MEASURE_PERSIST: today every frame is an independent zlib stream, so a

// frame can only back-reference itself. If the firmware instead kept one inflate

// stream alive across frames, later frames could back-reference the sliding-window

// history of earlier ones (and skip the per-frame zlib header/adler framing). This

// flag feeds every frame's raw bytes through a single deflate stream, flushing

// (Z_SYNC_FLUSH) at each frame boundary, and reports what the per-frame message

// sizes would then be — so we can judge whether the firmware complexity is worth it

// before implementing it. It doesn't change what gets streamed to the device.

import {

G2Session,

buildCreateStartUpPageContainer,

buildImageContainers,

buildImageRawData,

buildEvenHubBmp,

planImageFragments,

framePb,

sendFrames,

waitForAck,

FLAG_REQUEST,

8000

SID,

type ImageContainerSpec,

} from "g2-kit/ble";

import { startHeartbeat } from "g2-kit/ui";

import { deflateSync, createDeflate, constants as zconst } from "node:zlib";

import { GifReader } from "omggif";

import { lz4CompressBlock } from "./lz4";

const ACK_MS = 12_000;

const MODE = (process.env.G2_MODE ?? "delta").toLowerCase();

if (!["delta", "raw4", "lz4"].includes(MODE)) {

console.error(`G2_MODE must be one of delta|raw4|lz4 (got "${MODE}")`);

process.exit(1);

}

const LZ4 = MODE === "lz4";

const W = Math.max(16, Math.min(LZ4 ? 576 : 640, Number(process.env.G2_IMG_W ?? (LZ4 ? "288" : "640"))));

const H = Math.max(16, Math.min(LZ4 ? 288 : 480, Number(process.env.G2_IMG_H ?? (LZ4 ? "144" : "480"))));

if (!LZ4 && (W !== 640 || H !== 480)) {

console.error("CFW raw4/delta modes use a fixed 640x480 full-panel screen");

process.exit(1);

}

const THRESHOLD = Math.max(-1, Math.min(255, Number(process.env.G2_IMG_THRESHOLD ?? "-1")));

const MAX_FRAMES = Math.max(0, Number(process.env.G2_MAX_FRAMES ?? "0"));

const STRIDE = Math.max(1, Number(process.env.G2_FRAME_STRIDE ?? "1"));

const KEYFRAME_INTERVAL = Math.max(0, Number(process.env.G2_KEYFRAME_INTERVAL ?? "0"));

const RAW4 = MODE === "raw4"; // mode 6: full headerless packed-4bpp shadow

const DELTA = MODE === "delta"; // mode 6 keyframes + mode 3 bounding-box deltas

// Stock firmware sizes its decode buffer as W*H from the container geometry and hands

// LZ4_decompress_safe that as dstCapacity, so a payload inflating past W*H is refused

// on-device ("decompress failed"). Catch it here instead of on the lens.

const LZ4_DECODE_CAP = W * H;

/** CompressMode (ImgRawDataUpdate field 5) we put on the wire. 0 = uncompressed. */

const COMPRESS_MODE = LZ4 ? 2 : 0;

const DRY_RUN = process.env.G2_DRY_RUN === "1";

const MEASURE_PERSIST = process.env.G2_MEASURE_PERSIST === "1";

const WINDOW = Math.max(1, Number(process.env.G2_WINDOW ?? "2"));

const FRAME_SLEEP = Math.max(0, Number(process.env.G2_FRAME_SLEEP ?? "0"));

const IMAGE_SEND_ARM = (process.env.G2_IMAGE_ARM ?? "R").toUpperCase();

if (IMAGE_SEND_ARM !== "L" && IMAGE_SEND_ARM !== "R") {

console.error(`G2_IMAGE_ARM must be L or R (got "${process.env.G2_IMAGE_ARM}")`);

process.exit(1);

}

let magic = 100;

const nextMagic = () => (magic = magic >= 255 ? 100 : magic + 1);

const videoPath = process.argv[2] ?? process.env.G2_VIDEO;

if (!videoPath) {

console.error("usage: bun video-bench.ts <video.gif> (see header for ffmpeg one-liner)");

process.exit(1);

}

// ---- decode GIF -> grayscale frames at WxH (nearest-neighbor rescale) ----

const gifBuf = new Uint8Array(await Bun.file(videoPath).arrayBuffer());

const gif = new GifReader(gifBuf);

const W0 = gif.width, H0 = gif.height;

const total = gif.numFrames();

console.log(`[decode] ${videoPath}: ${W0}x${H0}, ${total} frames -> target ${W}x${H}`);

function rescaleGray(rgba: Uint8Array): Uint8Array {

const out = new Uint8Array(W * H);

if (THRESHOLD >= 0) {

for (let y = 0; y < H; y++) {

const sy = Math.min(H0 - 1, ((y * H0) / H) | 0);

for (let x = 0; x < W; x++) {

const sx = Math.min(W0 - 1, ((x * W0) / W) | 0);

const i = (sy * W0 + sx) * 4;

out[y * W + x] = (rgba[i]! > THRESHOLD ? 255 : 0);

}

return out;

} else {

for (let y = 0; y < H; y++) {

const sy = Math.min(H0 - 1, ((y * H0) / H) | 0);

for (let x = 0; x < W; x++) {

const sx = Math.min(W0 - 1, ((x * W0) / W) | 0);

const i = (sy * W0 + sx) * 4;

out[y * W + x] = (rgba[i]! * 0.299 + rgba[i + 1]! * 0.587 + rgba[i + 2]! * 0.114) | 0;

}

return out;

}

// ---- build per-frame payloads up front ([mode][zlib], modes 3/6 [mode][zlib(rle)]) ----

type FrameStat = { bytes: number; key: boolean; persist: number };

const payloads: Uint8Array[] = [];

const stats: FrameStat[] = [];

const rgba = new Uint8Array(W0 * H0 * 4);

let dispose: { x: number; y: number; w: number; h: number } | null = null;

let prev: Uint8Array | null = null;

let used = 0;

let boxAreaSum = 0; // sum of mode-3 box areas (px), for avg-coverage reporting

// Optional persistent-zlib measurement: one long-lived deflate stream fed every

// frame's raw (pre-compression) bytes in order, flushed at each frame boundary so

// we can read off the per-frame output size. Later frames get to back-reference

// the sliding-window history of earlier ones, which independent per-frame deflate

// throws away. Returns the compressed bytes emitted for the just-pushed frame.

let persistPush: ((raw: Uint8Array) => Promise<number>) | null = null;

if (MEASURE_PERSIST) {

const def = createDeflate();

let chunks: Buffer[] = [];

def.on("data", (c: Buffer) => chunks.push(c));

persistPush = (raw) =>

new Promise<number>((resolve, reject) => {

chunks = [];

def.write(raw, (e) => { if (e) reject(e); });

// Z_SYNC_FLUSH keeps the window/dictionary (cross-frame refs survive);

// Z_FULL_FLUSH would reset it and defeat the whole point of measuring.

def.flush(zconst.Z_SYNC_FLUSH, () => resolve(chunks.reduce((a, c) => a + c.length, 0)));

});

}

const t0 = performance.now();

for (let i = 0; i < total; i++) {

if (dispose) {

for (let yy = dispose.y; yy < dispose.y + dispose.h; yy++)

rgba.fill(0, (yy * W0 + dispose.x) * 4, (yy * W0 + dispose.x + dispose.w) * 4);

}

const fi = gif.frameInfo(i);

gif.d 8000 ecodeAndBlitFrameRGBA(i, rgba);

dispose = fi.disposal === 2 ? { x: fi.x, y: fi.y, w: fi.width, h: fi.height } : null;

if (i % STRIDE !== 0) continue;

const gray = rescaleGray(rgba);

// In delta mode a frame is a keyframe on the first frame or every Nth; raw4

// sends a keyframe every time.

const isKey = !DELTA || prev === null ||

(KEYFRAME_INTERVAL > 0 && used % KEYFRAME_INTERVAL === 0);

// Build this frame's payload. Simple modes are [mode][zlib(raw)]; the mode-3

// box carries a 4-byte uncompressed header before its zlib box pixels. For the

// persist measurement we also track the pre-compression bytes and the length of

// the uncompressed prefix (mode byte + any header).

let payload: Uint8Array, persistRaw: Uint8Array, prefixLen: number;

if (LZ4) {

// Stock 2.2.6.10: no mode byte and no zlib — the whole payload IS the LZ4 block,

// and CompressMode=2 on the message is what tells the firmware to inflate it.

persistRaw = buildEvenHubBmp(W, H, (x, y) => gray[y * W + x]! >> 4);

if (persistRaw.length > LZ4_DECODE_CAP) {

console.error(

`G2_MODE=lz4: a ${W}x${H} BMP is ${persistRaw.length} B but stock firmware only ` +

`allocates W*H = ${LZ4_DECODE_CAP} B to decompress into, so the lens would reject ` +

`it. Use a smaller frame.`);

process.exit(1);

}

payload = lz4CompressBlock(persistRaw); prefixLen = 0;

} else if (RAW4) {

// mode 6: headerless tight 4bpp (gray>>4), RLE'd then deflated into the

// direct-framebuffer shadow.

persistRaw = rleEncode(pack4bpp(gray));

payload = pack(6, persistRaw); prefixLen = 1;

} else if (isKey) {

// delta keyframe: mode 6 full 4bpp — seeds the firmware's persistent 4bpp

// shadow that subsequent bounding-box deltas composite onto.

persistRaw = rleEncode(pack4bpp(gray));

payload = pack(6, persistRaw); prefixLen = 1;

} else {

// mode 3: bounding-box delta — send only the changed rectangle as 4bpp, RLE'd

// then deflated.

const box = computeBox(gray, prev!);

boxAreaSum += box.w * box.h;

persistRaw = rleEncode(box.pixels);

payload = packBox(box, persistRaw, used & 0xffff); prefixLen = 7; // used = this frame's index

}

payloads.push(payload);

const persist = persistPush ? prefixLen + (await persistPush(persistRaw)) : 0;

stats.push({ bytes: payload.length, key: isKey, persist });

prev = gray;

used++;

if (MAX_FRAMES && used >= MAX_FRAMES) break;

if (used % 200 === 0) console.log(`[decode] ${used} frames prepared...`);

}

const prepMs = performance.now() - t0;

// Defensive check: the mode-3 (delta) payloads must carry strictly increasing,

// unique frame ids in the exact order they'll be sent (payloads are streamed in

// array order, writes awaited, so build order == send order). If this passes, the

// sender is NOT reordering/duplicating frames — so any reorder/dup/skip the

// firmware's diagnostic flags must originate in the transport or the firmware.

{

let prev = -1, bad = 0, n3 = 0;

for (const p of payloads) {

if (p[0] !== 3) continue; // only deltas carry a fid

n3++;

const fid = p[5]! | (p[6]! << 8);

if (fid <= prev) { if (bad++ < 5) console.error(`[check] delta fid ${fid} not > prev ${prev} (out-of-order/dup in build)`); }

prev = fid;

}

console.log(bad

? `[check] FAIL: ${bad}/${n3} delta fids out of order or duplicated in the build`

: `[check] ok: ${n3} delta fids strictly increasing & unique (send side is clean)`);

}

const keyBytes = stats.filter((s) => s.key).reduce((a, s) => a + s.bytes, 0);

const keyN = stats.filter((s) => s.key).length;

const deltaBytes = stats.filter((s) => !s.key).reduce((a, s) => a + s.bytes, 0);

const deltaN = stats.length - keyN;

const totalBytes = keyBytes + deltaBytes;

const boxCov = DELTA && deltaN ? ` | avg box ${(100 * boxAreaSum / (deltaN * W * H)).toFixed(1)}% of frame` : "";

console.log(

`[prepared] mode=${MODE} ${W}x${H} ${payloads.length} frames in ${(prepMs / 1000).toFixed(1)}s | ` +

`${(totalBytes / 1024).toFixed(0)} KiB total, avg ${(totalBytes / payloads.length).toFixed(0)} B/frame ` +

`(keyframes ${keyN}@${keyN ? (keyBytes / keyN).toFixed(0) : 0}B, deltas ${deltaN}@${deltaN ? (deltaBytes / deltaN).toFixed(0) : 0}B)${boxCov}`,

);

if (MEASURE_PERSIST) {

const pKeyBytes = stats.filter((s) => s.key).reduce((a, s) => a + s.persist, 0);

const pDeltaBytes = stats.filter((s) => !s.key).reduce((a, s) => a + s.persist, 0);

const pTotal = pKeyBytes + pDeltaBytes;

const deltaPct = totalBytes ? 100 * (1 - pTotal / totalBytes) : 0;

console.log(

`[persist] if zlib state persisted across frames: ${(pTotal / 1024).toFixed(0)} KiB total, ` +

`avg ${(pTotal / payloads.length).toFixed(0)} B/frame ` +

`(keyframes ${keyN}@${keyN ? (pKeyBytes / keyN).toFixed(0) : 0}B, deltas ${deltaN}@${deltaN ? (pDeltaBytes / deltaN).toFixed(0) : 0}B) ` +

`-> ${deltaPct >= 0 ? "saves" : "costs"} ${Math.abs(deltaPct).toFixed(1)}% vs per-frame deflate`,

);

}

function pack(mode: number, raw: Uint8Array): Uint8Array {

const z = deflateSync(raw);

const out = new Uint8Array(z.length + 1);

out[0] = mode;

out.set(z, 1);

return out;

}

// Run-length encode packed 4bpp pixels for CFW modes 3 and 6, whose payload is

// zlib(rle(pixels)) rather than zlib(pixels). Runs are over the pixel NIBBLES of

// `pix` in wire order (high nibble = left pixel), including the pad nibble that ends

// each row at odd widths — i.e. `pix` read as pix.length*2 nibbles. One token is:

// [cnt4|color4] cnt 1..15

// [0|color4][cnt8] cnt 1..255

// [0|color4][0][cntLo][cntHi] cnt 1..65535, little-endian

// with the low nibble always the color; runs longer than 65535 split across tokens.

// Worst case (every nibble its own run) is exactly one byte per nibble, which is what

// we size the buffer for.

function rleEncode(pix: Uint8Array): Uint8Array {

const n = pix.length * 2;

const out = new Uint8Array(n);

let o = 0;

const nib = (i: number) => (i & 1 ? pix[i >> 1]! & 0x0f : pix[i >> 1]! >> 4);

let i = 0;

while (i < n) {

const v = nib(i);

let j = i + 1;

while (j < n && nib(j) === v) j++;

let run = j - i;

while (run > 0) {

const c = Math.min(run, 0xffff);

if (c <= 15) {

out[o++] = (c << 4) | v;

} else if (c <= 255) {

out[o++] = v; // high nibble 0 = escape to an 8-bit count

out[o++] = c;

} else {

out[o++] = v;

out[o++] = 0; // 8-bit count 0 = escape to a 16-bit count

out[o++] = c & 0xff;

out[o++] = c >> 8;

}

run -= c;

}

i = j;

}

return out.subarray(0, o);

}

// Tightly-packed 4bpp (mode 6): gray 0..255 -> nibble (gray>>4), 2 px/byte with

// the left pixel in the high nibble, rows top-down, stride = ceil(W/2), no

// padding. Matches the firmware's headerless-4bpp expander.

function pack4bpp(gray: Uint8Array): Uint8Array {

const stride = (W + 1) >> 1;

const out = new Uint8Array(stride * H);

for (let y = 0; y < H; y++) {

for (let x = 0; x < W; x += 2) {

const hi = gray[y * W + x]! >> 4;

const lo = x + 1 < W ? gray[y * W + x + 1]! >> 4 : 0;

out[y * stride + (x >> 1)] = (hi << 4) | lo;

}

return out;

}

// mode 3: bounding box of the pixels whose displayed (4bpp) value changed vs the

// previous frame, quantized so left/width are multiples of 4 and top/height of 2

// (the units the wire header stores, and what the firmware requires). The box's

// pixels are extracted as tight 4bpp (gray>>4). If nothing changed, we emit a

// minimal 4x2 box at the origin (a no-op update) to keep every frame a message.

type Box = { left: number; top: number; w: number; h: number; pixels: Uint8Array };

function computeBox(cur: Uint8Array, prev: Uint8Array): Box {

let minx = W, miny = H, maxx = -1, maxy = -1;

for (let y = 0; y < H; y++) {

for (let x = 0; x < W; x++) {

const i = y * W + x;

if (cur[i]! >> 4 !== prev[i]! >> 4) {

if (x < minx) minx = x;

if (x > maxx) maxx = x;

if (y < miny) miny = y;

if (y > maxy) maxy = y;

}

if (maxx < 0) { minx = 0; maxx = 3; miny = 0; maxy = 1; } // no change -> tiny box

const left = minx & ~3;

const right = Math.min(W, (maxx + 4) & ~3); // round up to a multiple of 4

const top = miny & ~1;

const bottom = Math.min(H, (maxy + 2) & ~1); // round up to a multiple of 2

const w = right - left, h = bottom - top;

const stride = w >> 1;

const pixels = new Uint8Array(stride * h);

for (let y = 0; y < h; y++) {

for (let x = 0; x < w; x += 2) {

const hi = cur[(top + y) * W + left + x]! >> 4;

const lo = cur[(top + y) * W + left + x + 1]! >> 4; // w is even, so x+1 < w

pixels[y * stride + (x >> 1)] = (hi << 4) | lo;

}

return { left, top, w, h, pixels };

}

// [3][left/4][top/2][width/4][height/2][fid_lo][fid_hi][zlib(rle(tight 4bpp box pixels))]

// fid = uint16 per-frame counter, so the firmware can flag out-of-order/skipped frames.

// `rle` is the already-RLE'd box pixels (the caller keeps it for the persist measurement).

function packBox(box: Box, rle: Uint8Array, fid: number): Uint8Array {

const z = deflateSync(rle);

const out = new Uint8Array(7 + z.length);

out[0] = 3;

out[1] = box.left >> 2;

out[2] = box.top >> 1;

out[3] = box.w >> 2;

out[4] = box.h >> 1;

out[5] = fid & 0xff;

out[6] = (fid >> 8) & 0xff;

out.set(z, 7);

return out;

}

if (DRY_RUN) {

console.log("[dry-run] not sending. (re-run without G2_DRY_RUN=1 to stream to the device)");

process.exit(0);

}

const session = await G2Session.open();

const hb = startHeartbeat({ session, nextMagic });

const suffix = String(Date.now() % 10_000).padStart(4, "0");

try {

const create = buildCreateStartUpPageContainer({

name: `b${suffix}`, items: ["."], containerId: 1, captureEvents: false, magic: nextMagic(), extraContainerNames: [`c${suffix}`],

});

if (!(await session.sendPb(0xe0, create.pb, create.magic, { ackTimeoutMs: ACK_MS }))) throw new Error("CREATE did not ack");

const container: ImageContainerSpec = LZ4

? {

name: `c${suffix}`, containerId: 2,

x: Math.max(0, (576 - W) >> 1), y: Math.max(0, (288 - H) >> 1),

width: W, height: H,

}

: { name: `c${suffix}`, containerId: 2, x: 0, y: 0, width: 576, height: 288 };

const rebuild = buildImageContainers({ containers: [container], magic: nextMagic() });

if (!(await session.sendPb(0xe0, rebuild.pb, rebuild.magic, { ackTimeoutMs: ACK_MS }))) throw new Error("REBUILD did not ack");

// Layout is created on the default arm; we stream to IMAGE_SEND_ARM. Let the

// container replicate to that lens before the first frame to avoid a race.

await new Promise((r) => setTimeout(r, 300));

console.log(`[stream] sending ${payloads.length} frames, mode=${MODE}, window=${WINDOW}, arm=${IMAGE_SEND_ARM}...`);

let sid = 1, sent = 0, sentBytes = 0, aborted = false;

let latSum = 0, latN = 0, latWorst = 0;

const lats: number[] = [];

// Sliding window of in-flight acks: each image-raw message fires immediately

// (only its BLE write is awaited); we await the oldest ack before exceeding

// WINDOW outstanding, so the firmware sees backpressure but we don't pay a

// full ack round trip per message.

const inflight: Array<{ ack: Promise<unknown>; t: number }> = [];

const awaitOldest = async (): Promise<boolean> => {

const it = inflight.shift()!;

const ack = await it.ack;

const lat = performance.now() - it.t;

latSum += lat; latN++; if (lat > latWorst) latWorst = lat;

lats.push(lat);

return ack !== null;

};

// Fire one image message and return its pending ack, without awaiting it.

// For the R arm this is just session.sendPbPipelined. For L we hand-roll the

// same thing, because sendPbPipelined listens for the ack on whichever arm it

// wrote to and the ack for an image write always comes back on R. So: frames

// out on L, waiter registered on R. The L arm carries no other traffic here

// (heartbeat and setup both go to R), so it gets its own transport-seq counter

// rather than sharing the session's.

// The ack is returned wrapped in an object, as sendPbPipelined does, to defeat

// the async-return auto-unwrap that would otherwise await it right here.

let leftSeq = 0x40;

const sendPipelined = async (pb: Uint8Array, mg: number): Promise<{ ack: Promise<unknown> }> => {

if (IMAGE_SEND_ARM === "R") {

return session.sendPbPipelined(0xe0, pb, mg, { ackTimeoutMs: ACK_MS, arm: "R" });

}

const frames = framePb(pb, { seq: leftSeq, sid: SID.EVENHUB, flag: FLAG_REQUEST });

leftSeq = (leftSeq + 1) & 0xff;

const ack = waitForAck(session.right, SID.EVENHUB, mg, ACK_MS);

await sendFrames(session.left, frames);

return { ack };

};

const sendMsg = async (pb: Uint8Array, mg: number): Promise<boolean> => {

while (inflight.length >= WINDOW) {

if (!(await awaitOldest())) return false;

}

if (FRAME_SLEEP > 0) {

await new Promise((r) => setTimeout(r, FRAME_SLEEP));

}

const r = await sendPipelined(pb, mg);

inflight.push({ ack: r.ack, t: performance.now() });

return true;

};

const tStart = performance.now();

for (let i = 0; i < payloads.length; i++) {

for (const frag of planImageFragments(payloads[i]!, 4000)) {

const raw = buildImageRawData({

containerId: container.containerId, containerName: container.name, mapSessionId: sid,

mapTotalSize: payloads[i]!.length, mapFragmentIndex: frag.index,

mapRawData: frag.data, magic: nextMagic(), // packet size is derived from mapRawData.length

compressMode: COMPRESS_MODE,

});

if (!(await sendMsg(raw.pb, raw.magic))) { aborted = true; break; }

}

sid++;

if (aborted) { console.log(`[stream] frame ${i} NO_ACK — aborting`); break; }

sent++;

sentBytes += payloads[i]!.length;

if (sent % 100 === 0) {

const fps = sent / ((performance.now() - tStart) / 1000);

console.log(`[stream] ${sent}/${payloads.length} ${fps.toFixed(1)} fps ${(sentBytes / 1024).toFixed(0)} KiB`);

}

// drain the rest of the window so elapsed covers every ack

while (!aborted && inflight.length) {

if (!(await awaitOldest())) aborted = true;

}

const elapsed = (performance.now() - tStart) / 1000;

const fps = sent / elapsed;

// Percentiles over all observed ack latencies (nearest-rank on the sorted set).

const sortedLats = [...lats].sort((a, b) => a - b);

const pct = (p: number) =>

sortedLats.length ? sortedLats[Math.min(sortedLats.length - 1, Math.ceil(p * sortedLats.length) - 1)]! : 0;

const p90 = pct(0.9), p99 = pct(0.99);

// A worst >1000 ms almost certainly means the run ended on a timeout/disconnect,

// so the "worst" is that terminal stall, not a representative ack — surface the

// next-worst latency too so the tail is still readable.

const secondWorst = sortedLats.length >= 2 ? sortedLats[sortedLats.length - 2]! : 0;

const showSecond = latWorst > 1000 && sortedLats.length >= 2;

console.log(

`\n=== RESULT (mode=${MODE}, ${W}x${H}, window=${WINDOW}, arm=${IMAGE_SEND_ARM}) ===\n` +

`frames sent : ${sent}${aborted ? " (aborted early)" : ""}\n` +

`elapsed : ${elapsed.toFixed(1)} s\n` +

`framerate : ${fps.toFixed(2)} fps (${(1000 / fps).toFixed(0)} ms/frame)\n` +

`ack latency : avg ${latN ? (latSum / latN).toFixed(0) : 0} ms, p90 ${p90.toFixed(0)} ms, p99 ${p99.toFixed(0)} ms, worst ${latWorst.toFixed(0)} ms` +

`${showSecond ? ` (2nd-worst ${secondWorst.toFixed(0)} ms)` : ""} (round trip pipelining hides)\n` +

`wire image : ${(sentBytes / 1024).toFixed(0)} KiB (avg ${sent ? (sentBytes / sent).toFixed(0) : 0} B/frame, ${((sentBytes * 8) / elapsed / 1000).toFixed(0)} kbit/s)\n` +

`(image bytes only; protobuf+aa21 envelope add per-fragment overhead)`,

);

} finally {

hb.stop();

await session.close();

}

process.exit(0);

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