From f3b1f97afacc13d68d1fb3543c19b6ec9708a870 Mon Sep 17 00:00:00 2001
From: stef <19478336+stefpi@users.noreply.github.com>
Date: Tue, 16 Jun 2026 16:48:16 -0400
Subject: [PATCH] webrtc/athena: speed up first time stream connection (#38184)

* move streamrequest to models file, prewarm in webrtcd

* cleanup

* debug

* change print to logger.info
---
 system/athena/athenad.py      |  2 +-
 system/webrtc/device/video.py |  5 ++---
 system/webrtc/models.py       |  9 +++++++++
 system/webrtc/webrtcd.py      | 33 +++++++++++++++++++--------------
 4 files changed, 31 insertions(+), 18 deletions(-)
 create mode 100644 system/webrtc/models.py

diff --git a/system/athena/athenad.py b/system/athena/athenad.py
index c31f1ef281..4c9b536219 100755
--- a/system/athena/athenad.py
+++ b/system/athena/athenad.py
@@ -581,7 +581,7 @@ def getNetworks():
 
 @dispatcher.add_method
 def startStream(sdp: str, video_enabled: bool | None = None) -> dict:
-  from openpilot.system.webrtc.webrtcd import StreamRequestBody
+  from openpilot.system.webrtc.models import StreamRequestBody
   bridge_services_in = []
 
   # get live car params to avoid stale notCar edge case
diff --git a/system/webrtc/device/video.py b/system/webrtc/device/video.py
index af492c829e..69f628cb11 100644
--- a/system/webrtc/device/video.py
+++ b/system/webrtc/device/video.py
@@ -7,7 +7,7 @@ from teleoprtc.tracks import TiciVideoStreamTrack
 from aiortc import MediaStreamError
 
 from cereal import messaging
-from openpilot.common.realtime import DT_MDL, DT_DMON
+from openpilot.common.realtime import DT_MDL
 from openpilot.common.params import Params
 
 
@@ -30,8 +30,7 @@ class LiveStreamVideoStreamTrack(TiciVideoStreamTrack):
   }
 
   def __init__(self, camera_type: str, video_enabled: bool = True):
-    dt = DT_DMON if camera_type == "driver" else DT_MDL
-    super().__init__(camera_type, dt)
+    super().__init__(camera_type, DT_MDL)
 
     self._sock = self._make_sock(camera_type)
     self._pts = 0
diff --git a/system/webrtc/models.py b/system/webrtc/models.py
new file mode 100644
index 0000000000..fd74113049
--- /dev/null
+++ b/system/webrtc/models.py
@@ -0,0 +1,9 @@
+from dataclasses import dataclass, field
+
+@dataclass
+class StreamRequestBody:
+  sdp: str
+  initCamera: str
+  video_enabled: bool = True
+  bridge_services_in: list[str] = field(default_factory=list)
+  bridge_services_out: list[str] = field(default_factory=list)
diff --git a/system/webrtc/webrtcd.py b/system/webrtc/webrtcd.py
index 8d29dafdd3..48b868de21 100755
--- a/system/webrtc/webrtcd.py
+++ b/system/webrtc/webrtcd.py
@@ -10,7 +10,6 @@ import contextlib
 import json
 import uuid
 import logging
-from dataclasses import dataclass, field
 from typing import Any, TYPE_CHECKING
 
 # aiortc and its dependencies have lots of internal warnings :(
@@ -22,13 +21,13 @@ import capnp
 from aiohttp import web
 if TYPE_CHECKING:
   from aiortc.rtcdatachannel import RTCDataChannel
+import aioice.ice
 
+from openpilot.system.webrtc.models import StreamRequestBody
 from openpilot.system.webrtc.schema import generate_field
 from openpilot.common.params import Params
 from cereal import messaging, log
 
-import aioice.ice
-
 
 # socket trick: route lookup for 8.8.8.8 (nothing is sent or actually connected to)
 # return the source interfaces IP which is the default interface of the device
@@ -254,9 +253,10 @@ class StreamSession:
     enabled: bool | None = None,
     debug_mode: bool = False
   ):
-    from aiortc.mediastreams import VideoStreamTrack
+    if debug_mode:
+      from aiortc.mediastreams import VideoStreamTrack
     from openpilot.system.webrtc.device.video import LiveStreamVideoStreamTrack
-    from teleoprtc import WebRTCAnswerBuilder
+    from teleoprtc.builder import WebRTCAnswerBuilder
 
     self.identifier = str(uuid.uuid4())
     self.params = Params()
@@ -370,15 +370,6 @@ class StreamSession:
       await self.stream.stop()
 
 
-@dataclass
-class StreamRequestBody:
-  sdp: str
-  initCamera: str
-  video_enabled: bool = True
-  bridge_services_in: list[str] = field(default_factory=list)
-  bridge_services_out: list[str] = field(default_factory=list)
-
-
 async def get_stream(request: 'web.Request'):
   stream_dict, debug_mode = request.app['streams'], request.app['debug']
   raw_body = await request.json()
@@ -455,11 +446,25 @@ async def error_middleware(request: 'web.Request', handler):
     return web.json_response({"error": "exception", "message": f"{type(e).__name__}: {e}"}, status=500)
 
 
+def prewarm_stream_session_imports(debug_mode: bool = False) -> None:
+  if debug_mode:
+    from aiortc.mediastreams import VideoStreamTrack
+    assert VideoStreamTrack
+  from openpilot.system.webrtc.device.video import LiveStreamVideoStreamTrack
+  from teleoprtc.builder import WebRTCAnswerBuilder
+  assert LiveStreamVideoStreamTrack
+  assert WebRTCAnswerBuilder
+
+
 def webrtcd_thread(host: str, port: int, debug: bool):
   logging.basicConfig(level=logging.CRITICAL, handlers=[logging.StreamHandler()])
   logging_level = logging.DEBUG if debug else logging.INFO
   logging.getLogger("WebRTCStream").setLevel(logging_level)
   logging.getLogger("webrtcd").setLevel(logging_level)
+  prewarm_start = time.monotonic()
+  prewarm_stream_session_imports(debug)
+  prewarm_end = time.monotonic()
+  logging.getLogger("webrtcd").info(f"webrtc prewarm finished in {(prewarm_end - prewarm_start) * 1000} ms")
 
   app = web.Application(middlewares=[error_middleware])