diff --git a/litellm/llms/gemini/realtime/transformation.py b/litellm/llms/gemini/realtime/transformation.py index e64cbf88d95..a305f5927f4 100644 --- a/litellm/llms/gemini/realtime/transformation.py +++ b/litellm/llms/gemini/realtime/transformation.py @@ -132,7 +132,15 @@ def _grounding_metadata_from_frame(frame: Mapping[str, object]) -> tuple[Mapping # 175 text tokens/min of output (ai.google.dev/gemini-api/docs/pricing). GEMINI_LIVE_TRANSCRIBE_AUDIO_TOKENS_PER_SECOND: Final = 25 GEMINI_LIVE_TRANSCRIBE_OUTPUT_TEXT_TOKENS_PER_MINUTE: Final = 175 -PCM16_INPUT_AUDIO_BYTES_PER_SECOND: Final = 48000 + +# Live API input audio is natively 16kHz; 24kHz is the *output* rate. Per +# ai.google.dev/gemini-api/docs/live-api/capabilities: "Audio output always uses a sample +# rate of 24kHz. Input audio is natively 16kHz ... To convey the sample rate of input +# audio, set the MIME type of each audio-containing Blob to a value like +# audio/pcm;rate=16000." The MIME rate is what the server resamples against, so declaring +# the output rate on the input path mislabels correctly-encoded audio. +GEMINI_LIVE_INPUT_AUDIO_SAMPLE_RATE_HZ: Final = 16000 +PCM16_BYTES_PER_SAMPLE: Final = 2 def _base64_decoded_byte_count(data: str) -> int: @@ -150,6 +158,9 @@ class GeminiRealtimeConfig(BaseRealtimeConfig): # turns; buffer it here so the next response.done carries the token counts. self._pending_usage_metadata: dict | None = None self._unbilled_input_audio_bytes: int = 0 + # Overwritten from session.update when the client declares a rate; see + # _record_input_audio_sample_rate. + self._input_audio_sample_rate_hz: int = GEMINI_LIVE_INPUT_AUDIO_SAMPLE_RATE_HZ def is_setup_message(self, msg_obj: dict) -> bool: return "setup" in msg_obj @@ -243,7 +254,7 @@ class GeminiRealtimeConfig(BaseRealtimeConfig): def get_audio_mime_type(self, input_audio_format: str = "pcm16"): mime_types: Final = { - "pcm16": "audio/pcm;rate=24000", + "pcm16": f"audio/pcm;rate={self._input_audio_sample_rate_hz}", "g711_ulaw": "audio/pcmu", "g711_alaw": "audio/pcma", } @@ -463,6 +474,31 @@ class GeminiRealtimeConfig(BaseRealtimeConfig): ) return setup + def _record_input_audio_sample_rate(self, session_payload: Mapping[str, object]) -> None: + """ + Remember the input sample rate the client declared on session.update. + + The rate reaches Gemini only through the per-blob MIME type, and the server resamples + against whatever that MIME type claims, so it has to describe the bytes actually sent. + Only the GA session shape carries a rate (``audio.input.format.rate``); the beta shape's + ``input_audio_format`` is a bare codec name with no rate, and leaves the 16kHz default + in place. + """ + audio = session_payload.get("audio") + if not isinstance(audio, dict): + return + audio_input = audio.get("input") + if not isinstance(audio_input, dict): + return + audio_format = audio_input.get("format") + if not isinstance(audio_format, dict): + return + rate = audio_format.get("rate") + # bool is an int subclass, so exclude it explicitly. + if isinstance(rate, bool) or not isinstance(rate, int) or rate <= 0: + return + self._input_audio_sample_rate_hz = rate + def _handle_session_update( self, json_message: _OpenAIRealtimeClientEvent, @@ -488,6 +524,7 @@ class GeminiRealtimeConfig(BaseRealtimeConfig): # explicit modality / transcription / turn-detection settings # would be silently dropped because ``map_openai_params`` only # recognises the flat OpenAI-beta key names. + self._record_input_audio_sample_rate(session_payload) session_payload = self._normalize_session_payload_for_mapping(session_payload) new_overrides: Final = self.map_openai_params(optional_params={}, non_default_params=session_payload) @@ -1215,7 +1252,8 @@ class GeminiRealtimeConfig(BaseRealtimeConfig): """Gemini Live sends no usageMetadata for transcribe sessions; estimate billing from streamed audio duration.""" if self._unbilled_input_audio_bytes <= 0 or not self._is_text_only_live_model(model): return None - audio_seconds: Final = self._unbilled_input_audio_bytes / PCM16_INPUT_AUDIO_BYTES_PER_SECOND + bytes_per_second: Final = self._input_audio_sample_rate_hz * PCM16_BYTES_PER_SAMPLE + audio_seconds: Final = self._unbilled_input_audio_bytes / bytes_per_second self._unbilled_input_audio_bytes = 0 audio_tokens: Final = round(audio_seconds * GEMINI_LIVE_TRANSCRIBE_AUDIO_TOKENS_PER_SECOND) output_tokens: Final = round(audio_seconds * GEMINI_LIVE_TRANSCRIBE_OUTPUT_TEXT_TOKENS_PER_MINUTE / 60) diff --git a/litellm/llms/vertex_ai/realtime/transformation.py b/litellm/llms/vertex_ai/realtime/transformation.py index 9fed6d52f0e..d52d7e7ad3a 100644 --- a/litellm/llms/vertex_ai/realtime/transformation.py +++ b/litellm/llms/vertex_ai/realtime/transformation.py @@ -93,19 +93,6 @@ class VertexAIRealtimeConfig(GeminiRealtimeConfig): headers["x-goog-user-project"] = self._project return headers - # ------------------------------------------------------------------ - # Audio MIME type — Vertex AI needs the sample rate in the MIME string - # ------------------------------------------------------------------ - - def get_audio_mime_type(self, input_audio_format: str = "pcm16") -> str: - mime_types: Final = { - # Gemini Live native audio (OpenAI GA realtime default) is 24kHz PCM. - "pcm16": "audio/pcm;rate=24000", - "g711_ulaw": "audio/pcmu", - "g711_alaw": "audio/pcma", - } - return mime_types.get(input_audio_format, "application/octet-stream") - # ------------------------------------------------------------------ # Session setup message # ------------------------------------------------------------------ diff --git a/tests/unit/llms/gemini/realtime/test_gemini_realtime_transformation.py b/tests/unit/llms/gemini/realtime/test_gemini_realtime_transformation.py index bcd5f3d8d19..6ef4ae78bed 100644 --- a/tests/unit/llms/gemini/realtime/test_gemini_realtime_transformation.py +++ b/tests/unit/llms/gemini/realtime/test_gemini_realtime_transformation.py @@ -2007,10 +2007,102 @@ def _input_audio_append_message(raw_byte_count: int) -> str: ) +def _session_update_message(session: dict) -> str: + return json.dumps({"type": "session.update", "session": session}) + + +def _sent_audio_mime_type(config, raw_byte_count: int = 32000) -> str: + """Round-trips one input_audio_buffer.append and returns the mimeType actually put on the wire.""" + sent = config.transform_realtime_request( + _input_audio_append_message(raw_byte_count), "gemini-3.5-transcribe-live" + ) + return json.loads(sent[0])["realtimeInput"]["audio"]["mimeType"] + + +def test_input_audio_mime_type_declares_the_native_16khz_input_rate(): + """The Live API resamples against the MIME rate, and its documented native input rate is + 16kHz; 24kHz is the output rate. Declaring the output rate on the input path mislabels + correctly-encoded audio (ai.google.dev/gemini-api/docs/live-api/capabilities).""" + from typing import Final + + config: Final = GeminiRealtimeConfig() + assert config.get_audio_mime_type() == "audio/pcm;rate=16000" + assert _sent_audio_mime_type(config) == "audio/pcm;rate=16000" + + +def test_vertex_realtime_inherits_the_same_input_audio_rate(): + """VertexAIRealtimeConfig used to carry its own copy of get_audio_mime_type, so a fix to the + parent had no effect on the Vertex path. It must resolve through the parent now.""" + from typing import Final + + from litellm.llms.vertex_ai.realtime.transformation import VertexAIRealtimeConfig + + config: Final = VertexAIRealtimeConfig(access_token="t", project="p", location="us-central1") + assert "get_audio_mime_type" not in VertexAIRealtimeConfig.__dict__ + assert config.get_audio_mime_type() == "audio/pcm;rate=16000" + + +def test_client_declared_input_audio_rate_is_honored_on_the_wire(): + """A GA client that declares a non-native input rate must have that rate forwarded, not the + default; the whole point of the MIME rate is to describe the bytes actually sent.""" + from typing import Final + + config: Final = GeminiRealtimeConfig() + config.transform_realtime_request( + _session_update_message({"audio": {"input": {"format": {"type": "audio/pcm", "rate": 24000}}}}), + "gemini-3.5-transcribe-live", + ) + assert _sent_audio_mime_type(config) == "audio/pcm;rate=24000" + + +@pytest.mark.parametrize( + "session", + [ + {}, + {"audio": {}}, + {"audio": {"input": {}}}, + {"audio": {"input": {"format": "audio/pcm"}}}, + {"audio": {"input": {"format": {"type": "audio/pcm"}}}}, + {"audio": {"input": {"format": {"type": "audio/pcm", "rate": 0}}}}, + {"audio": {"input": {"format": {"type": "audio/pcm", "rate": -1}}}}, + {"audio": {"input": {"format": {"type": "audio/pcm", "rate": "24000"}}}}, + {"audio": {"input": {"format": {"type": "audio/pcm", "rate": True}}}}, + {"input_audio_format": "pcm16"}, + ], +) +def test_malformed_or_absent_declared_rate_keeps_the_native_default(session): + """Anything that is not a usable positive integer rate, including the rate-less beta shape and + a bool (which is an int subclass), must leave the 16kHz default alone rather than corrupt it.""" + from typing import Final + + config: Final = GeminiRealtimeConfig() + config.transform_realtime_request(_session_update_message(session), "gemini-3.5-transcribe-live") + assert _sent_audio_mime_type(config) == "audio/pcm;rate=16000" + + +def test_declared_rate_also_drives_the_billed_audio_duration(patch_gemini_transcribe_live_cost_map_entry): + """The MIME label and the duration estimate read the same rate, so a client that declares + 24kHz is billed for 24kHz audio: 96000 pcm16 bytes = 2s -> 50 in / 6 out.""" + from typing import Final + + config: Final = GeminiRealtimeConfig() + config.transform_realtime_request( + _session_update_message({"audio": {"input": {"format": {"type": "audio/pcm", "rate": 24000}}}}), + "gemini-3.5-transcribe-live", + ) + config.transform_realtime_request(_input_audio_append_message(96000), "gemini-3.5-transcribe-live") + + usage: Final = config.unbilled_usage_on_session_close("gemini-3.5-transcribe-live") + assert usage is not None + assert usage["input_tokens"] == 50 + assert usage["output_tokens"] == 6 + + def test_transcribe_live_completed_event_carries_estimated_usage(patch_gemini_transcribe_live_cost_map_entry): """Gemini Live sends no usageMetadata for transcribe sessions, so LiteLLM bills from streamed audio duration at Google's published estimate (25 audio tok/sec in, - 175 text tok/min out): 96000 pcm16 bytes = 2s at 24kHz -> 50 in / 6 out.""" + 175 text tok/min out): 96000 pcm16 bytes = 3s at the Live API's native 16kHz input + rate -> 75 in / 9 out.""" from typing import Final from litellm.types.llms.gemini import BidiGenerateContentServerMessage @@ -2048,10 +2140,10 @@ def test_transcribe_live_completed_event_carries_estimated_usage(patch_gemini_tr assert completed[0]["transcript"] == "ahoy there" expected_usage: Final[RealtimeInputAudioTranscriptionUsage] = { "type": "tokens", - "input_tokens": 50, - "output_tokens": 6, - "total_tokens": 56, - "input_token_details": {"text_tokens": 0, "audio_tokens": 50}, + "input_tokens": 75, + "output_tokens": 9, + "total_tokens": 84, + "input_token_details": {"text_tokens": 0, "audio_tokens": 75}, } assert completed[0]["usage"] == expected_usage @@ -2114,7 +2206,8 @@ def test_non_transcription_live_model_completed_event_has_no_usage(patch_gemini_ def test_unbilled_usage_on_session_close_flushes_trailing_audio(patch_gemini_transcribe_live_cost_map_entry): """Audio appended after the last transcript frame is still unbilled when the session closes; the session-close hook must hand back the estimate exactly once - so the streaming layer can bill it (144000 pcm16 bytes = 3s -> 75 in / 9 out).""" + so the streaming layer can bill it (144000 pcm16 bytes = 4.5s at the native 16kHz + input rate -> 112 in / 13 out; 112.5 rounds to even).""" from typing import Final from litellm.types.realtime import RealtimeInputAudioTranscriptionUsage @@ -2126,10 +2219,10 @@ def test_unbilled_usage_on_session_close_flushes_trailing_audio(patch_gemini_tra expected: Final[RealtimeInputAudioTranscriptionUsage] = { "type": "tokens", - "input_tokens": 75, - "output_tokens": 9, - "total_tokens": 84, - "input_token_details": {"text_tokens": 0, "audio_tokens": 75}, + "input_tokens": 112, + "output_tokens": 13, + "total_tokens": 125, + "input_token_details": {"text_tokens": 0, "audio_tokens": 112}, } assert usage == expected assert config.unbilled_usage_on_session_close("gemini-3.5-transcribe-live") is None