DailyTransport: add transport_source to transcription frames

changelog/3257.changed.2.md

@@ -0,0 +1 @@
+- `TranscriptionFrame` and `InterimTranscriptionFrame` produced by `DailyTransport` now include the transport source (i.e., the originating audio track).

src/pipecat/transports/daily/transport.py

@@ -2651,6 +2651,7 @@ class DailyTransport(BaseTransport):
 
         text = message["text"]
         timestamp = message["timestamp"]
+        track_type = message.get("trackType", None)
         raw_response = message.get("rawResponse", {})
         is_final = raw_response.get("is_final", False)
         try:
@@ -2669,6 +2670,7 @@ class DailyTransport(BaseTransport):
                 language,
                 result=message,
             )
+        frame.transport_source = track_type
 
         if self._input:
             await self._input.push_transcription_frame(frame)