From e217b315c23caffe620f2f1a2dca2cebbbf37a4c Mon Sep 17 00:00:00 2001
From: Koushik Dutta <koushd@gmail.com>
Date: Wed, 2 Mar 2022 10:33:33 -0800
Subject: [PATCH] rebroadcast: fix bug where packet length was parsed as signed
 integer.

---
 common/src/rtsp-server.ts                 |  8 +++++++-
 common/src/sdp-utils.ts                   | 19 +++++++++++++++++++
 plugins/prebuffer-mixin/package-lock.json |  4 ++--
 plugins/prebuffer-mixin/package.json      |  2 +-
 plugins/prebuffer-mixin/src/main.ts       |  8 +++++---
 plugins/prebuffer-mixin/src/rfc4571.ts    |  4 ++--
 6 files changed, 36 insertions(+), 9 deletions(-)

diff --git a/common/src/rtsp-server.ts b/common/src/rtsp-server.ts
index 5801a80a5..79722bf49 100644
--- a/common/src/rtsp-server.ts
+++ b/common/src/rtsp-server.ts
@@ -109,7 +109,13 @@ export class RtspClient extends RtspBase {
     async request(method: string, headers?: Headers, path?: string, body?: Buffer) {
         headers = headers || {};
 
-        const line = `${method} ${this.url}${path || ''} RTSP/1.0`;
+        let fullUrl: string;
+        if (path)
+            fullUrl = new URL(path, this.url).toString();
+        else
+            fullUrl = this.url;
+
+        const line = `${method} ${fullUrl} RTSP/1.0`;
         headers['CSeq'] = (this.cseq++).toString();
         this.write(line, headers, body);
 
diff --git a/common/src/sdp-utils.ts b/common/src/sdp-utils.ts
index 2c5af111b..84c036cbc 100644
--- a/common/src/sdp-utils.ts
+++ b/common/src/sdp-utils.ts
@@ -15,3 +15,22 @@ export function parsePayloadTypes(sdp: string) {
         videoPayloadTypes,
     }
 }
+
+function getTrackId(track: string) {
+    if (!track)
+        return;
+    const lines = track.split('\n').map(line => line.trim());
+    const control = lines.find(line => line.startsWith('a=control:'));
+    return control?.split('a=control:')?.[1];
+}
+
+export function parseTrackIds(sdp: string) {
+    const tracks = sdp.split('m=');
+
+    const audioTrack = tracks.find(track => track.startsWith('audio'));
+    const videoTrack = tracks.find(track => track.startsWith('video'));
+    return {
+        audio: getTrackId(audioTrack),
+        video: getTrackId(videoTrack),
+    };
+}
diff --git a/plugins/prebuffer-mixin/package-lock.json b/plugins/prebuffer-mixin/package-lock.json
index d0b098596..19a799470 100644
--- a/plugins/prebuffer-mixin/package-lock.json
+++ b/plugins/prebuffer-mixin/package-lock.json
@@ -1,12 +1,12 @@
 {
    "name": "@scrypted/prebuffer-mixin",
-   "version": "0.1.170",
+   "version": "0.1.171",
    "lockfileVersion": 2,
    "requires": true,
    "packages": {
       "": {
          "name": "@scrypted/prebuffer-mixin",
-         "version": "0.1.170",
+         "version": "0.1.171",
          "license": "Apache-2.0",
          "dependencies": {
             "@scrypted/common": "file:../../common",
diff --git a/plugins/prebuffer-mixin/package.json b/plugins/prebuffer-mixin/package.json
index 7d1f559d3..13c81739c 100644
--- a/plugins/prebuffer-mixin/package.json
+++ b/plugins/prebuffer-mixin/package.json
@@ -1,6 +1,6 @@
 {
    "name": "@scrypted/prebuffer-mixin",
-   "version": "0.1.170",
+   "version": "0.1.171",
    "description": "Rebroadcast and Prebuffer for VideoCameras.",
    "author": "Scrypted",
    "license": "Apache-2.0",
diff --git a/plugins/prebuffer-mixin/src/main.ts b/plugins/prebuffer-mixin/src/main.ts
index 0ac97c289..db73c50b0 100644
--- a/plugins/prebuffer-mixin/src/main.ts
+++ b/plugins/prebuffer-mixin/src/main.ts
@@ -7,7 +7,7 @@ import { handleRebroadcasterClient, ParserOptions, ParserSession, startParserSes
 import { createMpegTsParser, createFragmentedMp4Parser, StreamChunk, StreamParser } from '@scrypted/common/src/stream-parser';
 import { AutoenableMixinProvider } from '@scrypted/common/src/autoenable-mixin-provider';
 import { listenZeroSingleClient } from '@scrypted/common/src/listen-cluster';
-import { parsePayloadTypes } from '@scrypted/common/src/sdp-utils';
+import { parsePayloadTypes, parseTrackIds } from '@scrypted/common/src/sdp-utils';
 import { createRtspParser, RtspClient, RtspServer } from '@scrypted/common/src/rtsp-server';
 import { Duplex } from 'stream';
 import net from 'net';
@@ -446,8 +446,10 @@ class PrebufferSession {
         const sdpResponse = await rtspClient.describe();
         const sdp = sdpResponse.body.toString().trim();
         this.sdp = Promise.resolve(sdp);
-        await rtspClient.setup(0, '/audio');
-        await rtspClient.setup(2, '/video');
+        const { audio, video } = parseTrackIds(sdp);
+        // handle no audio?
+        await rtspClient.setup(0, audio);
+        await rtspClient.setup(2, video);
         const socket = await rtspClient.play();
         session = await startRFC4571Parser(socket, sdp, ffmpegInput.mediaStreamOptions, true, rbo);
       }
diff --git a/plugins/prebuffer-mixin/src/rfc4571.ts b/plugins/prebuffer-mixin/src/rfc4571.ts
index 3f502c0da..f33020d6a 100644
--- a/plugins/prebuffer-mixin/src/rfc4571.ts
+++ b/plugins/prebuffer-mixin/src/rfc4571.ts
@@ -70,11 +70,11 @@ export async function startRFC4571Parser(socket: net.Socket, sdp: string, mediaS
             let length: number;
             if (hasRstpPrefix) {
                 header = await readLength(socket, 4);
-                length = header.readInt16BE(2);
+                length = header.readUInt16BE(2);
             }
             else {
                 header = await readLength(socket, 2);
-                length = header.readInt16BE(0);
+                length = header.readUInt16BE(0);
             }
             const data = await readLength(socket, length);