From d9c900f872a44e9f7e4583f1131d353bfdf127a7 Mon Sep 17 00:00:00 2001
From: Mark Backman <mark@daily.co>
Date: Sat, 12 Oct 2024 21:27:37 -0400
Subject: [PATCH] Satisfy minimal text requirements for Cartesia and OpenAI

---
 src/pipecat/services/cartesia.py               | 4 ++--
 src/pipecat/services/openai.py                 | 2 +-
 src/pipecat/utils/text/markdown_text_filter.py | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/pipecat/services/cartesia.py b/src/pipecat/services/cartesia.py
index 5166a3df8..c0e4a89a2 100644
--- a/src/pipecat/services/cartesia.py
+++ b/src/pipecat/services/cartesia.py
@@ -152,7 +152,7 @@ class CartesiaTTSService(WordTTSService):
                 voice_config["__experimental_controls"]["emotion"] = self._settings["emotion"]
 
         msg = {
-            "transcript": text,
+            "transcript": text or " ",  # Text must contain at least one character
             "continue": continue_transcript,
             "context_id": self._context_id,
             "model_id": self.model_name,
@@ -271,7 +271,7 @@ class CartesiaTTSService(WordTTSService):
                 yield TTSStartedFrame()
                 self._context_id = str(uuid.uuid4())
 
-            msg = self._build_msg(text=text)
+            msg = self._build_msg(text=text or " ")  # Text must contain at least one character
 
             try:
                 await self._get_websocket().send(msg)
diff --git a/src/pipecat/services/openai.py b/src/pipecat/services/openai.py
index 2f98a7e10..f530d924b 100644
--- a/src/pipecat/services/openai.py
+++ b/src/pipecat/services/openai.py
@@ -409,7 +409,7 @@ class OpenAITTSService(TTSService):
             await self.start_ttfb_metrics()
 
             async with self._client.audio.speech.with_streaming_response.create(
-                input=text,
+                input=text or " ",  # Text must contain at least one character
                 model=self.model_name,
                 voice=VALID_VOICES[self._voice_id],
                 response_format="pcm",
diff --git a/src/pipecat/utils/text/markdown_text_filter.py b/src/pipecat/utils/text/markdown_text_filter.py
index d7203e6e7..d91922e32 100644
--- a/src/pipecat/utils/text/markdown_text_filter.py
+++ b/src/pipecat/utils/text/markdown_text_filter.py
@@ -96,7 +96,7 @@ class MarkdownTextFilter(BaseTextFilter):
             # Restore leading and trailing spaces
             filtered_text = re.sub("§", " ", filtered_text)
 
-            return filtered_text or " "  # Return a space to satisfy TTS services
+            return filtered_text
         else:
             return text