New feature: ability to force bitrates when transcoding, ignoring HomeKit's requested bitrates.

Author: hjdhjd

docs/FeatureOptions.md

@@ -138,7 +138,9 @@ These option(s) apply to: Protect cameras.
 |--------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 | `Video.Transcode.Hardware`                       | Use hardware-accelerated transcoding when available (Apple Macs, Intel Quick Sync Video-enabled CPUs, Raspberry Pi 4). **(default: disabled)**.
 | `Video.Transcode`                                | When streaming to local clients (e.g. at home), always transcode livestreams, instead of transmuxing them. **(default: disabled)**.
+| `Video.Transcode.Bitrate<I>.Value</I>`           | Bitrate, in kilobits per second, to use when transcoding to local clients, ignoring the bitrate HomeKit requests. HomeKit typically requests lower video quality than you may desire in your environment. **(default: 2000)**.
 | `Video.Transcode.HighLatency`                    | When streaming to high-latency clients (e.g. cellular connections), transcode livestreams instead of transmuxing them. **(default: enabled)**.
+| `Video.Transcode.HighLatency.Bitrate<I>.Value</I>`  | Bitrate, in kilobits per second, to use when transcoding to high-latency (e.g. cellular) clients, ignoring the bitrate HomeKit requests. HomeKit typically requests lower video quality than you may desire in your environment. **(default: 1000)**.
 | `Video.Stream.Only.High`                         | When viewing livestreams, force the use of the high quality video stream from the Protect controller. **(default: disabled)**.
 | `Video.Stream.Only.Medium`                       | When viewing livestreams, force the use of the medium quality video stream from the Protect controller. **(default: disabled)**.
 | `Video.Stream.Only.Low`                          | When viewing livestreams, force the use of the low quality video stream from the Protect controller. **(default: disabled)**.

src/devices/protect-camera.ts

@@ -73,9 +73,22 @@ export class ProtectCamera extends ProtectDevice {
     this.hints.smartDetect = this.ufp.featureFlags.hasSmartDetect && this.hasFeature("Motion.SmartDetect");
     this.hints.timeshift = this.hasFeature("Video.HKSV.TimeshiftBuffer");
     this.hints.transcode = this.hasFeature("Video.Transcode");
+    this.hints.transcodeBitrate = this.getFeatureNumber("Video.Transcode.Bitrate") as number;
     this.hints.transcodeHighLatency = this.hasFeature("Video.Transcode.HighLatency");
+    this.hints.transcodeHighLatencyBitrate = this.getFeatureNumber("Video.Transcode.HighLatency.Bitrate") as number;
     this.hints.twoWayAudio = this.ufp.featureFlags.hasSpeaker && this.hasFeature("Audio") && this.hasFeature("Audio.TwoWay");
 
+    // Sanity check our target transcoding bitrates, if defined.
+    if((this.hints.transcodeBitrate === undefined) || (this.hints.transcodeBitrate <= 0)) {
+
+      this.hints.transcodeBitrate = -1;
+    }
+
+    if((this.hints.transcodeHighLatencyBitrate === undefined) || (this.hints.transcodeHighLatencyBitrate <= 0)) {
+
+      this.hints.transcodeHighLatencyBitrate = -1;
+    }
+
     return true;
   }
 

src/devices/protect-device.ts

@@ -47,7 +47,9 @@ export interface ProtectHints {
   syncName: boolean,
   timeshift: boolean,
   transcode: boolean,
+  transcodeBitrate: number,
   transcodeHighLatency: boolean,
+  transcodeHighLatencyBitrate: number,
   twoWayAudio: boolean
 }
 

src/protect-options.ts

@@ -3,7 +3,8 @@
  * protect-options.ts: Feature option and type definitions for UniFi Protect.
  */
 import { PROTECT_DEVICE_REMOVAL_DELAY_INTERVAL, PROTECT_DOORBELL_CHIME_DURATION_DIGITAL, PROTECT_FFMPEG_AUDIO_FILTER_FFTNR, PROTECT_FFMPEG_AUDIO_FILTER_HIGHPASS,
-  PROTECT_FFMPEG_AUDIO_FILTER_LOWPASS, PROTECT_M3U_PLAYLIST_PORT, PROTECT_MOTION_DURATION, PROTECT_OCCUPANCY_DURATION } from "./settings.js";
+  PROTECT_FFMPEG_AUDIO_FILTER_LOWPASS, PROTECT_M3U_PLAYLIST_PORT, PROTECT_MOTION_DURATION, PROTECT_OCCUPANCY_DURATION, PROTECT_TRANSCODE_BITRATE,
+  PROTECT_TRANSCODE_HIGH_LATENCY_BITRATE } from "./settings.js";
 import { ProtectDeviceConfigTypes } from "./protect-types.js";
 import { ProtectNvrConfig } from "unifi-protect";
 
@@ -133,7 +134,9 @@ export const featureOptions: { [index: string]: FeatureOption[] } = {
 
     { default: false, description: "Use hardware-accelerated transcoding when available (Apple Macs, Intel Quick Sync Video-enabled CPUs, Raspberry Pi 4).", name: "Transcode.Hardware" },
     { default: false, description: "When streaming to local clients (e.g. at home), always transcode livestreams, instead of transmuxing them.", name: "Transcode" },
+    { default: false, defaultValue: PROTECT_TRANSCODE_BITRATE, description: "Bitrate, in kilobits per second, to use when transcoding to local clients, ignoring the bitrate HomeKit requests. HomeKit typically requests lower video quality than you may desire in your environment.", group: "Transcode", name: "Transcode.Bitrate" },
     { default: true, description: "When streaming to high-latency clients (e.g. cellular connections), transcode livestreams instead of transmuxing them.", name: "Transcode.HighLatency" },
+    { default: false, defaultValue: PROTECT_TRANSCODE_HIGH_LATENCY_BITRATE, description: "Bitrate, in kilobits per second, to use when transcoding to high-latency (e.g. cellular) clients, ignoring the bitrate HomeKit requests. HomeKit typically requests lower video quality than you may desire in your environment.", group: "Transcode.HighLatency", name: "Transcode.HighLatency.Bitrate" },
     { default: false, description: "When viewing livestreams, force the use of the high quality video stream from the Protect controller.", name: "Stream.Only.High" },
     { default: false, description: "When viewing livestreams, force the use of the medium quality video stream from the Protect controller.", name: "Stream.Only.Medium" },
     { default: false, description: "When viewing livestreams, force the use of the low quality video stream from the Protect controller.", name: "Stream.Only.Low" },

src/protect-stream.ts

@@ -394,8 +394,11 @@ export class ProtectStreamingDelegate implements CameraStreamingDelegate {
     // How do we determine if we're a high latency connection? We look at the RTP packet time of the audio packet time for a hint. HomeKit uses values of 20, 30, 40,
     // and 60ms. We make an assumption, validated by lots of real-world testing, that when we see 60ms used by HomeKit, it's a high latency connection and act
     // accordingly.
-    const isTranscoding = this.protectCamera.hints.transcode || this.protectCamera.hints.crop ||
-      ((request.audio.packet_time >= 60) && this.protectCamera.hints.transcodeHighLatency);
+    const isHighLatency = request.audio.packet_time >= 60;
+    const isTranscoding = this.protectCamera.hints.transcode || this.protectCamera.hints.crop || (isHighLatency && this.protectCamera.hints.transcodeHighLatency);
+
+    // Set the initial bitrate we should use for this request based on what HomeKit is requesting.
+    let targetBitrate = request.video.max_bit_rate;
 
     // Find the best RTSP stream based on what we're looking for.
     if(isTranscoding) {
@@ -405,6 +408,21 @@ export class ProtectStreamingDelegate implements CameraStreamingDelegate {
         (this.protectCamera.hints.hardwareTranscoding) ? 2160 : request.video.height,
         { biasHigher: true, maxPixels: this.ffmpegOptions.hostSystemMaxPixels }
       );
+
+      // If we have specified the bitrates we want to use when transcoding, let's honor those here.
+      if(isHighLatency && (this.protectCamera.hints.transcodeHighLatencyBitrate > 0)) {
+
+        targetBitrate = this.protectCamera.hints.transcodeHighLatencyBitrate;
+      } else if(!isHighLatency && (this.protectCamera.hints.transcodeBitrate > 0)) {
+
+        targetBitrate = this.protectCamera.hints.transcodeBitrate;
+      }
+
+      // If we're targeting a bitrate that's beyond the capabilities of our input channel, match the bitrate of the input channel.
+      if(this.rtspEntry && (targetBitrate > (this.rtspEntry.channel.bitrate / 1000))) {
+
+        targetBitrate = this.rtspEntry.channel.bitrate / 1000;
+      }
     } else {
 
       this.rtspEntry = this.protectCamera.findRtsp(request.video.width, request.video.height);
@@ -421,8 +439,7 @@ export class ProtectStreamingDelegate implements CameraStreamingDelegate {
       return;
     }
 
-    // Save our current bitrate before we modify it, but only if we're the first stream - we don't want to do this for
-    // concurrent streaming clients for this camera.
+    // Save our current bitrate before we modify it, but only if we're the first stream - we don't want to do this for concurrent streaming clients for this camera.
     if(!this.savedBitrate) {
 
       this.savedBitrate = this.protectCamera.getBitrate(this.rtspEntry.channel.id);
@@ -435,7 +452,7 @@ export class ProtectStreamingDelegate implements CameraStreamingDelegate {
 
     // Set the desired bitrate in Protect. We don't need to for this to return, because Protect
     // will adapt the stream once it processes the configuration change.
-    await this.protectCamera.setBitrate(this.rtspEntry.channel.id, request.video.max_bit_rate * 1000);
+    await this.protectCamera.setBitrate(this.rtspEntry.channel.id, targetBitrate * 1000);
 
     // Set our packet size to be 564. Why? MPEG transport stream (TS) packets are 188 bytes in size each.
     // These packets transmit the video data that you ultimately see on your screen and are transmitted using
@@ -494,7 +511,7 @@ export class ProtectStreamingDelegate implements CameraStreamingDelegate {
     // Inform the user.
     this.log.info("Streaming request from %s%s: %sx%s@%sfps, %s kbps. %s %s, %s kbps.",
       sessionInfo.address, (request.audio.packet_time === 60) ? " (high latency connection)" : "",
-      request.video.width, request.video.height, request.video.fps, request.video.max_bit_rate.toLocaleString("en-US"),
+      request.video.width, request.video.height, request.video.fps, targetBitrate.toLocaleString("en-US"),
       isTranscoding ? (this.protectCamera.hints.hardwareTranscoding ? "Hardware accelerated transcoding" : "Transcoding") : "Using",
       this.rtspEntry.name, (this.rtspEntry.channel.bitrate / 1000).toLocaleString("en-US"));
 
@@ -504,7 +521,7 @@ export class ProtectStreamingDelegate implements CameraStreamingDelegate {
       // Configure our video parameters for transcoding.
       ffmpegArgs.push(...this.ffmpegOptions.streamEncoder({
 
-        bitrate: request.video.max_bit_rate,
+        bitrate: targetBitrate,
         fps: this.rtspEntry.channel.fps,
         height: request.video.height,
         idrInterval: PROTECT_HOMEKIT_IDR_INTERVAL,

src/settings.ts

@@ -77,5 +77,11 @@ export const PROTECT_RPI_GPU_MINIMUM = 128;
 // Maximum age of a snapshot in seconds.
 export const PROTECT_SNAPSHOT_CACHE_MAXAGE = 90;
 
+// Bitrate, in kilobits per second, to use when transcoding to local clients.
+export const PROTECT_TRANSCODE_BITRATE = 2000;
+
+// Bitrate, in kilobits per second, to use when transcoding to high-latency clients.
+export const PROTECT_TRANSCODE_HIGH_LATENCY_BITRATE = 1000;
+
 // How often, in seconds, should we heartbeat FFmpeg in two-way audio sessions. This should be less than 5 seconds, which is FFmpeg's input timeout interval.
 export const PROTECT_TWOWAY_HEARTBEAT_INTERVAL = 3;