Update publish_hue to publish at 30fps (#323)

Author: davidzhao

examples/publish_hue.py

@@ -3,12 +3,13 @@
 import logging
 import os
 from signal import SIGINT, SIGTERM
+from time import perf_counter
 
 import numpy as np
 from livekit import api, rtc
 
 WIDTH, HEIGHT = 1280, 720
-
+FPS = 30
 
 # ensure LIVEKIT_URL, LIVEKIT_API_KEY, and LIVEKIT_API_SECRET are set
 
@@ -38,8 +39,14 @@ async def main(room: rtc.Room):
     # publish a track
     source = rtc.VideoSource(WIDTH, HEIGHT)
     track = rtc.LocalVideoTrack.create_video_track("hue", source)
-    options = rtc.TrackPublishOptions()
-    options.source = rtc.TrackSource.SOURCE_CAMERA
+    options = rtc.TrackPublishOptions(
+        source=rtc.TrackSource.SOURCE_CAMERA,
+        simulcast=True,
+        video_encoding=rtc.VideoEncoding(
+            max_framerate=FPS,
+            max_bitrate=3_000_000,
+        ),
+    )
     publication = await room.local_participant.publish_track(track, options)
     logging.info("published track %s", publication.sid)
 
@@ -50,12 +57,11 @@ async def draw_color_cycle(source: rtc.VideoSource):
     argb_frame = bytearray(WIDTH * HEIGHT * 4)
     arr = np.frombuffer(argb_frame, dtype=np.uint8)
 
-    framerate = 1 / 30
+    framerate = 1 / FPS
     hue = 0.0
+    next_frame_time = perf_counter()
 
     while True:
-        start_time = asyncio.get_event_loop().time()
-
         rgb = colorsys.hsv_to_rgb(hue, 1.0, 1.0)
         rgb = [(x * 255) for x in rgb]  # type: ignore
 
@@ -69,8 +75,10 @@ async def draw_color_cycle(source: rtc.VideoSource):
         source.capture_frame(frame)
         hue = (hue + framerate / 3) % 1.0
 
-        code_duration = asyncio.get_event_loop().time() - start_time
-        await asyncio.sleep(1 / 30 - code_duration)
+        # code_duration = perf_counter() - start_time
+        next_frame_time += 1 / FPS
+        await asyncio.sleep(next_frame_time - perf_counter())
+        # await asyncio.sleep(1 / FPS - code_duration)
 
 
 if __name__ == "__main__":