add support for TTS model (#2095)

### What problem does this PR solve?

add support for TTS model
#1853

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

---------

Co-authored-by: Zhedong Cen <cenzhedong2@126.com>
Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

rag/llm/tts_model.py

@@ -0,0 +1,94 @@
+#
+#  Copyright 2024 The InfiniFlow Authors. All Rights Reserved.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+#
+
+from typing import Annotated, Literal
+from abc import ABC
+import httpx
+import ormsgpack
+from pydantic import BaseModel, conint
+from rag.utils import num_tokens_from_string
+import json
+
+
+class ServeReferenceAudio(BaseModel):
+    audio: bytes
+    text: str
+
+
+class ServeTTSRequest(BaseModel):
+    text: str
+    chunk_length: Annotated[int, conint(ge=100, le=300, strict=True)] = 200
+    # Audio format
+    format: Literal["wav", "pcm", "mp3"] = "mp3"
+    mp3_bitrate: Literal[64, 128, 192] = 128
+    # References audios for in-context learning
+    references: list[ServeReferenceAudio] = []
+    # Reference id
+    # For example, if you want use https://fish.audio/m/7f92f8afb8ec43bf81429cc1c9199cb1/
+    # Just pass 7f92f8afb8ec43bf81429cc1c9199cb1
+    reference_id: str | None = None
+    # Normalize text for en & zh, this increase stability for numbers
+    normalize: bool = True
+    # Balance mode will reduce latency to 300ms, but may decrease stability
+    latency: Literal["normal", "balanced"] = "normal"
+
+
+class Base(ABC):
+    def __init__(self, key, model_name, base_url):
+        pass
+
+    def transcription(self, audio):
+        pass
+
+
+class FishAudioTTS(Base):
+    def __init__(self, key, model_name, base_url="https://api.fish.audio/v1/tts"):
+        if not base_url:
+            base_url = "https://api.fish.audio/v1/tts"
+        key = json.loads(key)
+        self.headers = {
+            "api-key": key.get("fish_audio_ak"),
+            "content-type": "application/msgpack",
+        }
+        self.ref_id = key.get("fish_audio_refid")
+        self.base_url = base_url
+
+    def transcription(self, text):
+        from http import HTTPStatus
+
+        request = request = ServeTTSRequest(text=text, reference_id=self.ref_id)
+
+        with httpx.Client() as client:
+            try:
+                with client.stream(
+                    method="POST",
+                    url=self.base_url,
+                    content=ormsgpack.packb(
+                        request, option=ormsgpack.OPT_SERIALIZE_PYDANTIC
+                    ),
+                    headers=self.headers,
+                    timeout=None,
+                ) as response:
+                    if response.status_code == HTTPStatus.OK:
+                        for chunk in response.iter_bytes():
+                            yield chunk
+                    else:
+                        response.raise_for_status()
+
+                yield num_tokens_from_string(text)
+
+            except httpx.HTTPStatusError as e:
+                raise RuntimeError(f"**ERROR**: {e}")