diff --git a/src/pipecat/serializers/base_serializer.py b/src/pipecat/serializers/base_serializer.py
index 71d274cff..83613d9ce 100644
--- a/src/pipecat/serializers/base_serializer.py
+++ b/src/pipecat/serializers/base_serializer.py
@@ -12,9 +12,9 @@ from pipecat.frames.frames import Frame
 class FrameSerializer(ABC):
 
     @abstractmethod
-    def serialize(self, frame: Frame) -> bytes:
+    def serialize(self, frame: Frame) -> str | bytes | None:
         pass
 
     @abstractmethod
-    def deserialize(self, data: bytes) -> Frame | None:
+    def deserialize(self, data: str | bytes) -> Frame | None:
         pass
diff --git a/src/pipecat/serializers/protobuf.py b/src/pipecat/serializers/protobuf.py
index c51fe8869..0a6dee0b1 100644
--- a/src/pipecat/serializers/protobuf.py
+++ b/src/pipecat/serializers/protobuf.py
@@ -26,7 +26,7 @@ class ProtobufFrameSerializer(FrameSerializer):
     def __init__(self):
         pass
 
-    def serialize(self, frame: Frame) -> bytes:
+    def serialize(self, frame: Frame) -> str | bytes | None:
         proto_frame = frame_protos.Frame()
         if type(frame) not in self.SERIALIZABLE_TYPES:
             raise ValueError(
@@ -41,7 +41,7 @@ class ProtobufFrameSerializer(FrameSerializer):
         result = proto_frame.SerializeToString()
         return result
 
-    def deserialize(self, data: bytes) -> Frame | None:
+    def deserialize(self, data: str | bytes) -> Frame | None:
         """Returns a Frame object from a Frame protobuf. Used to convert frames
         passed over the wire as protobufs to Frame objects used in pipelines
         and frame processors.
diff --git a/src/pipecat/serializers/TwilioFrameSerializer.py b/src/pipecat/serializers/twilio.py
similarity index 100%
rename from src/pipecat/serializers/TwilioFrameSerializer.py
rename to src/pipecat/serializers/twilio.py
diff --git a/src/pipecat/utils/audio.py b/src/pipecat/utils/audio.py
index e1ee4698b..a3fc1b0ab 100644
--- a/src/pipecat/utils/audio.py
+++ b/src/pipecat/utils/audio.py
@@ -33,6 +33,7 @@ def calculate_audio_volume(audio: bytes, sample_rate: int) -> float:
 def exp_smoothing(value: float, prev_value: float, factor: float) -> float:
     return prev_value + factor * (value - prev_value)
 
+
 def ulaw_8000_to_pcm_16000(ulaw_8000_bytes):
     # Convert μ-law to PCM
     pcm_8000_bytes = audioop.ulaw2lin(ulaw_8000_bytes, 2)
@@ -42,6 +43,7 @@ def ulaw_8000_to_pcm_16000(ulaw_8000_bytes):
 
     return pcm_16000_bytes
 
+
 def pcm_16000_to_ulaw_8000(pcm_16000_bytes):
     # Resample from 16000 Hz to 8000 Hz
     pcm_8000_bytes = audioop.ratecv(pcm_16000_bytes, 2, 1, 16000, 8000, None)[0]
@@ -49,4 +51,4 @@ def pcm_16000_to_ulaw_8000(pcm_16000_bytes):
     # Convert PCM to μ-law
     ulaw_8000_bytes = audioop.lin2ulaw(pcm_8000_bytes, 2)
 
-    return ulaw_8000_bytes
\ No newline at end of file
+    return ulaw_8000_bytes