140 lines
3.2 KiB
TypeScript
140 lines
3.2 KiB
TypeScript
// Screen-share quality presets modelled on Discord's tiers. Values are the
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// upper bounds — LiveKit + WebRTC's congestion control dynamically drop to
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// lower spatial/temporal layers (SVC with VP9) when the uplink degrades, so
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// these numbers behave as "up to" caps, not constant bitrates.
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const STORAGE_KEY = 'chatapp.screenshare';
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export type ScreenSharePreset =
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| 'auto'
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| '720p30'
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| '720p60'
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| '1080p30'
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| '1080p60'
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| '1440p60'
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| '4k60';
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export interface ScreenShareSettings {
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preset: ScreenSharePreset;
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}
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const DEFAULTS: ScreenShareSettings = {
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preset: 'auto',
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};
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export interface PresetParams {
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dims: { width: number; height: number } | null; // null = browser picks native
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framerate: number;
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bitrateKbps: number;
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label: string;
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}
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const PRESET_PARAMS: Record<ScreenSharePreset, PresetParams> = {
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auto: { dims: null, framerate: 60, bitrateKbps: 8000, label: 'Auto (Original)' },
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'720p30': {
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dims: { width: 1280, height: 720 },
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framerate: 30,
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bitrateKbps: 2500,
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label: '720p · 30 fps',
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},
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'720p60': {
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dims: { width: 1280, height: 720 },
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framerate: 60,
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bitrateKbps: 3500,
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label: '720p · 60 fps',
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},
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'1080p30': {
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dims: { width: 1920, height: 1080 },
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framerate: 30,
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bitrateKbps: 4000,
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label: '1080p · 30 fps',
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},
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'1080p60': {
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dims: { width: 1920, height: 1080 },
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framerate: 60,
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bitrateKbps: 6000,
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label: '1080p · 60 fps',
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},
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'1440p60': {
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dims: { width: 2560, height: 1440 },
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framerate: 60,
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bitrateKbps: 8000,
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label: '1440p · 60 fps',
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},
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'4k60': {
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dims: { width: 3840, height: 2160 },
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framerate: 60,
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bitrateKbps: 10_000,
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label: '4K · 60 fps',
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},
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};
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export const PRESET_ORDER: ReadonlyArray<ScreenSharePreset> = [
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'auto',
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'720p30',
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'720p60',
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'1080p30',
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'1080p60',
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'1440p60',
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'4k60',
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];
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export function getPresetParams(p: ScreenSharePreset): PresetParams {
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return PRESET_PARAMS[p];
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}
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type Listener = (s: ScreenShareSettings) => void;
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const listeners = new Set<Listener>();
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let cached: ScreenShareSettings | null = null;
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function isPreset(v: unknown): v is ScreenSharePreset {
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return typeof v === 'string' && v in PRESET_PARAMS;
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}
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function read(): ScreenShareSettings {
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if (cached) return cached;
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try {
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const raw = window.localStorage.getItem(STORAGE_KEY);
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if (!raw) {
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cached = DEFAULTS;
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return cached;
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}
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const parsed = JSON.parse(raw) as Partial<ScreenShareSettings>;
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cached = {
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preset: isPreset(parsed.preset) ? parsed.preset : DEFAULTS.preset,
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};
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return cached;
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} catch {
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cached = DEFAULTS;
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return cached;
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}
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}
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function write(s: ScreenShareSettings): void {
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cached = s;
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try {
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window.localStorage.setItem(STORAGE_KEY, JSON.stringify(s));
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} catch {
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/* quota / private mode */
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}
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for (const l of listeners) l(s);
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}
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export function getScreenShareSettings(): ScreenShareSettings {
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return read();
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}
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export function updateScreenShareSettings(
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patch: Partial<ScreenShareSettings>,
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): ScreenShareSettings {
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const next = { ...read(), ...patch };
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write(next);
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return next;
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}
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export function subscribeScreenShareSettings(listener: Listener): () => void {
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listeners.add(listener);
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return () => listeners.delete(listener);
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}
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