Add "Maximum video bitrate" option

src/assets/css/number-stepper.styl

@@ -3,7 +3,7 @@
 
     span {
         display: inline-block;
-        width: 40px;
+        min-width: 40px;
         font-family: var(--bx-monospaced-font);
         font-size: 14px;
     }

src/modules/ui/global-settings.ts

@@ -27,6 +27,9 @@ const SETTINGS_UI = {
         items: [
             PrefKey.STREAM_TARGET_RESOLUTION,
             PrefKey.STREAM_CODEC_PROFILE,
+
+            PrefKey.BITRATE_VIDEO_MAX,
+
             PrefKey.AUDIO_ENABLE_VOLUME_CONTROL,
             PrefKey.AUDIO_MIC_ON_PLAYING,
             PrefKey.STREAM_DISABLE_FEEDBACK_DIALOG,

src/utils/monkey-patches.ts

@@ -2,6 +2,7 @@ import { BxEvent } from "@utils/bx-event";
 import { getPref, PrefKey } from "@utils/preferences";
 import { STATES } from "@utils/global";
 import { BxLogger } from "@utils/bx-logger";
+import { patchSdpBitrate } from "./sdp";
 
 export function patchVideoApi() {
     const PREF_SKIP_SPLASH_VIDEO = getPref(PrefKey.SKIP_SPLASH_VIDEO);
@@ -96,6 +97,22 @@ export function patchRtcPeerConnection() {
         return dataChannel;
     }
 
+    const nativeSetLocalDescription = RTCPeerConnection.prototype.setLocalDescription;
+    RTCPeerConnection.prototype.setLocalDescription = function(description?: RTCLocalSessionDescriptionInit): Promise<void> {
+        // set maximum bitrate
+        try {
+            const maxVideoBitrate = getPref(PrefKey.BITRATE_VIDEO_MAX);
+            if (maxVideoBitrate > 0) {
+                arguments[0].sdp = patchSdpBitrate(arguments[0].sdp, maxVideoBitrate * 1000);
+            }
+        } catch (e) {
+            BxLogger.error('setLocalDescription', e);
+        }
+
+        // @ts-ignore
+        return nativeSetLocalDescription.apply(this, arguments);
+    };
+
     const OrgRTCPeerConnection = window.RTCPeerConnection;
     // @ts-ignore
     window.RTCPeerConnection = function() {

src/utils/preferences.ts

@@ -32,6 +32,8 @@ export enum PrefKey {
 
     STREAM_DISABLE_FEEDBACK_DIALOG = 'stream_disable_feedback_dialog',
 
+    BITRATE_VIDEO_MAX = 'bitrate_video_max',
+
     GAME_BAR_POSITION = 'game_bar_position',
 
     LOCAL_CO_OP_ENABLED = 'local_co_op_enabled',
@@ -314,6 +316,28 @@ export class Preferences {
             default: false,
         },
 
+        [PrefKey.BITRATE_VIDEO_MAX]: {
+            type: SettingElementType.NUMBER_STEPPER,
+            label: 'Maximum video bitrate',
+            default: 0,
+            min: 0,
+            max: 15,
+            steps: 1,
+            params: {
+                suffix: ' Mb/s',
+                exactTicks: 5,
+                customTextValue: (value: any) => {
+                    value = parseInt(value);
+
+                    if (value === 0) {
+                        return t('default');
+                    }
+
+                    return null;
+                },
+            },
+        },
+
         [PrefKey.GAME_BAR_POSITION]: {
             label: t('position'),
             default: 'bottom-left',

src/utils/sdp.ts

@@ -0,0 +1,61 @@
+export function patchSdpBitrate(sdp: string, video?: number, audio?: number) {
+    const lines = sdp.split('\n');
+
+    const mediaSet: Set<string> = new Set();
+    !!video && mediaSet.add('video');
+    !!audio && mediaSet.add('audio');
+
+    const bitrate = {
+        video,
+        audio,
+    };
+
+    for (let lineNumber = 0; lineNumber < lines.length; lineNumber++) {
+        let media: string = '';
+
+        let line = lines[lineNumber];
+        if (!line.startsWith('m=')) {
+            continue;
+        }
+
+        for (const m of mediaSet) {
+            if (line.startsWith(`m=${m}`)) {
+                media = m;
+                // Remove matched media from set
+                mediaSet.delete(media);
+                break;
+            }
+        }
+
+        // Invalid media, continue looking
+        if (!media) {
+            continue;
+        }
+
+        const bLine = `b=AS:${bitrate[media as keyof typeof bitrate]}`;
+
+        while (lineNumber++, lineNumber < lines.length) {
+            line = lines[lineNumber];
+            // Ignore lines that start with "i=" or "c="
+            if (line.startsWith('i=') || line.startsWith('c=')) {
+                continue;
+            }
+
+            if (line.startsWith('b=AS:')) {
+                // Replace bitrate
+                lines[lineNumber] = bLine;
+                // Stop lookine for "b=AS:" line
+                break;
+            }
+
+            if (line.startsWith('m=')) {
+                // "b=AS:" line not found, add "b" line before "m="
+                lines.splice(lineNumber, 0, bLine);
+                // Stop
+                break;
+            }
+        }
+    }
+
+    return lines.join('\n');
+}

src/utils/settings.ts

@@ -12,6 +12,8 @@ type NumberStepperParams = {
 
     ticks?: number;
     exactTicks?: number;
+
+    customTextValue?: (value: any) => string | null;
 }
 
 export enum SettingElementType {
@@ -131,9 +133,24 @@ export class SettingElement {
         const MAX = setting.max!;
         const STEPS = Math.max(setting.steps || 1, 1);
 
+        const renderTextValue = (value: any) => {
+            value = parseInt(value as string);
+
+            let textContent = null;
+            if (options.customTextValue) {
+                textContent = options.customTextValue(value);
+            }
+
+            if (textContent === null) {
+                textContent = value.toString() + options.suffix;
+            }
+
+            return textContent;
+        };
+
         const $wrapper = CE('div', {'class': 'bx-number-stepper'},
                             $decBtn = CE('button', {'data-type': 'dec'}, '-') as HTMLButtonElement,
-                            $text = CE('span', {}, value + options.suffix) as HTMLSpanElement,
+                            $text = CE('span', {}, renderTextValue(value)) as HTMLSpanElement,
                             $incBtn = CE('button', {'data-type': 'inc'}, '+') as HTMLButtonElement,
                            );
 
@@ -141,8 +158,7 @@ export class SettingElement {
             $range = CE('input', {'type': 'range', 'min': MIN, 'max': MAX, 'value': value, 'step': STEPS}) as HTMLInputElement;
             $range.addEventListener('input', e => {
                 value = parseInt((e.target as HTMLInputElement).value);
-
-                $text.textContent = value + options.suffix;
+                $text.textContent = renderTextValue(value);
                 onChange && onChange(e, value);
             });
             $wrapper.appendChild($range);
@@ -204,7 +220,7 @@ export class SettingElement {
                 value = Math.min(MAX, value + STEPS);
             }
 
-            $text.textContent = value.toString() + options.suffix;
+            $text.textContent = renderTextValue(value);
             $range && ($range.value = value.toString());
 
             isHolding = false;
@@ -237,7 +253,7 @@ export class SettingElement {
 
         // Custom method
         ($wrapper as any).setValue = (value: any) => {
-            $text.textContent = value + options.suffix;
+            $text.textContent = renderTextValue(value);
             $range && ($range.value = value);
         };