Live stream fails when LPCM audio is present

[galindocode]

Which version are you using?

v1.15.3

Which operating system are you using?

Linux amd64 Docker

Describe the issue

I am streaming video from Dahua recorders and noticed that channels utilizing LPCM audio do not work over WebRTC. Furthermore, over HLS, these channels are slow and sometimes fail to load

{
  "name": "test",
  "confName": "ttest",
  "source": {
    "type": "rtspSource",
    "id": ""
  },
  "ready": true,
  "readyTime": "2025-11-19T00:21:10.889560822Z",
  "tracks": [
    "H264",
    "LPCM"
  ],
  "bytesReceived": 47244,
  "bytesSent": 27864,
  "readers": [
    {
      "type": "hlsMuxer",
      "id": ""
    }
  ]
}

Describe how to replicate the issue

1. start the MediaMTX
2. publish with:

{
  "name": "test",
  "source": "rtsp://admin:admin123@192.168.1.12:554/cam/realmonitor?channel=9&subtype=1",
  "sourceFingerprint": "",
  "sourceOnDemand": true,
  "sourceOnDemandStartTimeout": "10s",
  "sourceOnDemandCloseAfter": "10s",
  "maxReaders": 0,
  "srtReadPassphrase": "",
  "fallback": "",
  "useAbsoluteTimestamp": false,
  "record": false,
  "recordPath": "./recordings/%path/%Y-%m-%d_%H-%M-%S-%f",
  "recordFormat": "fmp4",
  "recordPartDuration": "1s",
  "recordMaxPartSize": "50M",
  "recordSegmentDuration": "5m0s",
  "recordDeleteAfter": "10m0s",
  "overridePublisher": true,
  "srtPublishPassphrase": "",
  "rtspTransport": "automatic",
  "rtspAnyPort": false,
  "rtspRangeType": "",
  "rtspRangeStart": "",
  "rtspUDPReadBufferSize": 0,
  "mpegtsUDPReadBufferSize": 0,
  "rtpSDP": "",
  "rtpUDPReadBufferSize": 0,
  "sourceRedirect": "",
  "rpiCameraCamID": 0,
  "rpiCameraSecondary": false,
  "rpiCameraWidth": 1920,
  "rpiCameraHeight": 1080,
  "rpiCameraHFlip": false,
  "rpiCameraVFlip": false,
  "rpiCameraBrightness": 0,
  "rpiCameraContrast": 1,
  "rpiCameraSaturation": 1,
  "rpiCameraSharpness": 1,
  "rpiCameraExposure": "normal",
  "rpiCameraAWB": "auto",
  "rpiCameraAWBGains": [
    0,
    0
  ],
  "rpiCameraDenoise": "off",
  "rpiCameraShutter": 0,
  "rpiCameraMetering": "centre",
  "rpiCameraGain": 0,
  "rpiCameraEV": 0,
  "rpiCameraROI": "",
  "rpiCameraHDR": false,
  "rpiCameraTuningFile": "",
  "rpiCameraMode": "",
  "rpiCameraFPS": 30,
  "rpiCameraAfMode": "continuous",
  "rpiCameraAfRange": "normal",
  "rpiCameraAfSpeed": "normal",
  "rpiCameraLensPosition": 0,
  "rpiCameraAfWindow": "",
  "rpiCameraFlickerPeriod": 0,
  "rpiCameraTextOverlayEnable": false,
  "rpiCameraTextOverlay": "%Y-%m-%d %H:%M:%S - MediaMTX",
  "rpiCameraCodec": "auto",
  "rpiCameraIDRPeriod": 60,
  "rpiCameraBitrate": 5000000,
  "rpiCameraHardwareH264Profile": "main",
  "rpiCameraHardwareH264Level": "4.1",
  "rpiCameraSoftwareH264Profile": "baseline",
  "rpiCameraSoftwareH264Level": "4.1",
  "rpiCameraMJPEGQuality": 60,
  "runOnInit": "",
  "runOnInitRestart": false,
  "runOnDemand": "",
  "runOnDemandRestart": false,
  "runOnDemandStartTimeout": "10s",
  "runOnDemandCloseAfter": "10s",
  "runOnUnDemand": "",
  "runOnReady": "",
  "runOnReadyRestart": false,
  "runOnNotReady": "",
  "runOnRead": "",
  "runOnReadRestart": false,
  "runOnUnread": "",
  "runOnRecordSegmentCreate": "",
  "runOnRecordSegmentComplete": ""
}

3. read with Webrtc and HLS:

MediaMTX configuration

No response

MediaMTX logs

2025/11/18 20:35:13 INF [path test] [RTSP source] ready: 2 tracks (H264, LPCM)
2025/11/18 20:35:13 INF [WebRTC] [session 0aff1d97] created by 127.0.0.1:59312
2025/11/18 20:35:14 INF [WebRTC] [session 7a09e073] closed: codecs not supported by client
2025/11/18 20:35:14 INF [WebRTC] [session 0aff1d97] closed: codecs not supported by client
2025/11/18 20:35:16 WAR [path test] [RTSP source] no UDP packets received, switching to TCP
2025/11/18 20:35:16 INF [WebRTC] [session 8fee5c82] created by 127.0.0.1:59312
2025/11/18 20:35:17 INF [WebRTC] [session 8fee5c82] closed: codecs not supported by client
2025/11/18 20:35:19 INF [WebRTC] [session c978d1a2] created by 127.0.0.1:59312
2025/11/18 20:35:20 INF [WebRTC] [session c978d1a2] closed: codecs not supported by client
2025/11/18 20:35:22 INF [WebRTC] [session 5a0f5ba4] created by 127.0.0.1:59312
2025/11/18 20:35:23 INF [WebRTC] [session 5a0f5ba4] closed: codecs not supported by client

Network dump

No response