Apply audio resample filter correctly

Author: bonnieking

src/ac_training_lab/picam/device.py

@@ -232,11 +232,11 @@ def start_stream(ffmpeg_url, stream_key):
             "lavfi",
             "-i",
             "anullsrc=channel_layout=stereo:sample_rate=44100",
-            "-af",
-            "aresample=async=1:first_pts=0",
         ]
         + input_opts
         + [
+            "-filter:a",
+            "aresample=async=1:first_pts=0",
             "-c:v",
             "libx264",
             "-preset",