Any-to-Any
Transformers
Safetensors
lfm3_audio
automatic-speech-recognition
liquid
lfm3
audio
speech
edge
conversational
multilingual
custom_code
Instructions to use LiquidAI/LFM3-Audio-2B with libraries, inference providers, notebooks, and local apps. Follow these links to get started.
- Libraries
- Transformers
How to use LiquidAI/LFM3-Audio-2B with Transformers:
# pip install -U transformers accelerate # Load model directly from transformers import AutoModelForMultimodalLM model = AutoModelForMultimodalLM.from_pretrained("LiquidAI/LFM3-Audio-2B", trust_remote_code=True, device_map="auto") - Notebooks
- Google Colab
- Kaggle
Download processing_lfm3_audio.py from LiquidAI/LFM3-Audio-2B: direct link, hf CLI and curl.
- Browser
- Download file 18.7 kB
-
https://huggingface.co/LiquidAI/LFM3-Audio-2B/resolve/main/processing_lfm3_audio.py
- Command line
-
hf download hf://LiquidAI/LFM3-Audio-2B/processing_lfm3_audio.py
-
curl -L -o processing_lfm3_audio.py https://huggingface.co/LiquidAI/LFM3-Audio-2B/resolve/main/processing_lfm3_audio.py
18.7 kB
| # Copyright 2026 The HuggingFace Team. 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. | |
| """Processor class for LFM3-Audio.""" | |
| import copy | |
| import math | |
| import os | |
| import re | |
| from typing import TypedDict | |
| import numpy as np | |
| import torch | |
| from transformers.audio_utils import AudioInput, make_list_of_audio | |
| from transformers.configuration_utils import PreTrainedConfig | |
| from transformers.feature_extraction_utils import BatchFeature | |
| from transformers.processing_utils import ProcessingKwargs, ProcessorMixin | |
| from transformers.utils import TensorType, auto_docstring | |
| from .modeling_liquid_codec import LiquidCodecModel | |
| # The prompt format of the training data: ChatML turns, one placeholder per clip, no thinking block | |
| DEFAULT_CHAT_TEMPLATE = ( | |
| "{{- bos_token -}}" | |
| "{%- for message in messages -%}" | |
| "{{- '<|im_start|>' + message['role'] + '\\n' -}}" | |
| "{%- if message['content'] is string -%}{{- message['content'] -}}" | |
| "{%- else -%}{%- for content in message['content'] -%}" | |
| "{%- if content['type'] == 'audio' -%}{{- '<|audio|>' -}}" | |
| "{%- elif content['type'] == 'audio_out' -%}{{- '<|audio_out|>' -}}" | |
| "{%- elif content['type'] == 'text' -%}{{- content['text'] -}}" | |
| "{%- endif -%}{%- endfor -%}{%- endif -%}" | |
| "{{- '<|im_end|>\\n' -}}" | |
| "{%- endfor -%}" | |
| "{%- if add_generation_prompt -%}{{- '<|im_start|>assistant\\n' -}}{%- endif -%}" | |
| ) | |
| class Lfm3AudioFeatureExtractorKwargs(TypedDict, total=False): | |
| """ | |
| sampling_rate (`int`, *optional*): | |
| The sampling rate of the clips, which must be the extractor's own; it is checked, never resampled. | |
| return_tensors (`str` or [`~utils.TensorType`], *optional*): | |
| The tensor type of the returned features. | |
| load_audio_backend (`str`, *optional*): | |
| The decoding backend `apply_chat_template` loads audio with; the extractor itself ignores it. | |
| """ | |
| # the extractor always right-pads to whole frames and returns the mask, so the padding, truncation and | |
| # attention-mask options of `AudioKwargs` are not offered rather than silently dropped | |
| sampling_rate: int | None | |
| return_tensors: str | TensorType | None | |
| load_audio_backend: str | None | |
| class Lfm3AudioProcessorKwargs(ProcessingKwargs, total=False): | |
| audio_kwargs: Lfm3AudioFeatureExtractorKwargs | |
| _defaults = {} | |
| class Lfm3AudioProcessor(ProcessorMixin): | |
| r""" | |
| Wraps the LFM3-Audio feature extractor, the LFM3 tokenizer and optionally the Liquid codec. The text carries one | |
| `audio_token` per input clip and one `audio_out_token` per output clip or speech frame of the prompt; the | |
| processor expands the clips to their encoder tokens (one per 8 spectrogram frames) and codec frames. The two | |
| placeholder tokens are added to the tokenizer when it does not define them: the model replaces their embeddings | |
| with the speech features, so they never reach the model as text. | |
| """ | |
| attributes = ["feature_extractor", "tokenizer"] | |
| tokenizer_class = "AutoTokenizer" | |
| audio_tokenizer_class = "LiquidCodecModel" | |
| valid_processor_kwargs = Lfm3AudioProcessorKwargs | |
| def __init__( | |
| self, | |
| feature_extractor=None, | |
| tokenizer=None, | |
| audio_tokenizer=None, | |
| chat_template=None, | |
| audio_token: str = "<|audio|>", | |
| audio_out_token: str = "<|audio_out|>", | |
| **kwargs, | |
| ): | |
| r""" | |
| feature_extractor ([`Lfm3AudioFeatureExtractor`]): | |
| The feature extractor computing the log-mel spectrograms. | |
| tokenizer ([`PreTrainedTokenizerFast`]): | |
| The LFM3 tokenizer. | |
| audio_tokenizer ([`LiquidCodecModel`], *optional*): | |
| The codec turning 24 kHz output clips into speech frames. | |
| chat_template (`str`, *optional*): | |
| A Jinja template to turn conversations into prompts. | |
| audio_token (`str`, *optional*, defaults to `"<|audio|>"`): | |
| The placeholder token of one encoded frame of an input clip. | |
| audio_out_token (`str`, *optional*, defaults to `"<|audio_out|>"`): | |
| The placeholder token of one speech frame of the prompt. | |
| """ | |
| self.audio_token = getattr(tokenizer, "audio_token", audio_token) | |
| self.audio_out_token = getattr(tokenizer, "audio_out_token", audio_out_token) | |
| missing = [ | |
| token | |
| for token in (self.audio_token, self.audio_out_token) | |
| if tokenizer.convert_tokens_to_ids(token) in (None, tokenizer.unk_token_id) | |
| ] | |
| if missing: | |
| tokenizer.add_tokens(missing, special_tokens=True) | |
| self.audio_token_id = tokenizer.convert_tokens_to_ids(self.audio_token) | |
| self.audio_out_token_id = tokenizer.convert_tokens_to_ids(self.audio_out_token) | |
| if chat_template is None: | |
| chat_template = DEFAULT_CHAT_TEMPLATE | |
| super().__init__(feature_extractor, tokenizer, chat_template=chat_template) | |
| # a released transformers only accepts its own codec classes as `audio_tokenizer` | |
| self.audio_tokenizer = audio_tokenizer | |
| def from_pretrained(cls, pretrained_model_name_or_path, *args, audio_tokenizer=None, **kwargs): | |
| # `ProcessorMixin` forwards unknown kwargs to the tokenizer loader, which would keep the codec object in the | |
| # tokenizer config and break `save_pretrained` | |
| processor = super().from_pretrained(pretrained_model_name_or_path, *args, **kwargs) | |
| if audio_tokenizer is not None: | |
| processor.audio_tokenizer = audio_tokenizer | |
| return processor | |
| def to_dict(self): | |
| # `ProcessorMixin.to_dict` deep-copies the attributes; the codec weights are saved on their own. A shallow | |
| # clone drops the codec, so concurrent calls on `self` keep it. | |
| clone = copy.copy(self) | |
| codec = clone.__dict__.pop("audio_tokenizer", None) | |
| output = ProcessorMixin.to_dict(clone) | |
| if codec is not None: | |
| output["audio_tokenizer_subfolder"] = "audio_tokenizer" | |
| return output | |
| def save_pretrained(self, save_directory, push_to_hub=False, **kwargs): | |
| files = super().save_pretrained(save_directory, push_to_hub=False, **kwargs) | |
| if getattr(self, "audio_tokenizer", None) is not None: | |
| self.audio_tokenizer.save_pretrained(os.path.join(save_directory, "audio_tokenizer")) | |
| if push_to_hub: | |
| repo_id = kwargs.pop("repo_id", os.path.basename(os.path.abspath(save_directory))) | |
| self.push_to_hub(repo_id, **kwargs) | |
| return files | |
| def get_processor_dict(cls, pretrained_model_name_or_path, **kwargs): | |
| codec_kwargs = { | |
| key: value | |
| for key, value in kwargs.items() | |
| if key in ("cache_dir", "force_download", "local_files_only", "token", "revision") | |
| } | |
| parent = kwargs.get("subfolder") or "" | |
| processor_dict, kwargs = super().get_processor_dict(pretrained_model_name_or_path, **kwargs) | |
| if "processor_class" not in processor_dict: | |
| config, _ = PreTrainedConfig.get_config_dict( | |
| pretrained_model_name_or_path, subfolder=parent, **codec_kwargs | |
| ) | |
| if config.get("model_type") == "lfm3_audio" and config.get("format_version") == 1: | |
| # Legacy exports carry the text-only tokenizer template, not the trained audio prompt format. | |
| processor_dict["chat_template"] = DEFAULT_CHAT_TEMPLATE | |
| subfolder = processor_dict.pop("audio_tokenizer_subfolder", None) | |
| if subfolder is not None: | |
| if subfolder != "audio_tokenizer": | |
| raise ValueError("Expected the bundled codec in the audio_tokenizer subfolder") | |
| codec_class = LiquidCodecModel | |
| processor_dict["audio_tokenizer"] = codec_class.from_pretrained( | |
| pretrained_model_name_or_path, subfolder=os.path.join(parent, subfolder), **codec_kwargs | |
| ) | |
| return processor_dict, kwargs | |
| def __call__(self, text=None, audio: AudioInput | None = None, audio_out: AudioInput | None = None, **kwargs): | |
| r""" | |
| audio_out (`np.ndarray`, `torch.Tensor` or a list of them, *optional*): | |
| 24 kHz clips, one per `audio_out_token` in the text, encoded with the codec into `audio_out_codes`; the | |
| placeholder is repeated once per frame plus once for the end-of-speech frame that closes every clip. | |
| """ | |
| # the shared audio loader indexes the first clip before `validate_inputs` runs | |
| for name, clips in (("audio", audio), ("audio_out", audio_out)): | |
| if isinstance(clips, (list, tuple)) and len(clips) == 0: | |
| raise ValueError(f"`{name}` must hold at least one clip; pass `{name}=None` for prompts without one") | |
| if audio_out is None: | |
| return super().__call__(text=text, audio=audio, **kwargs) | |
| if text is None: | |
| raise ValueError("`audio_out` needs the text holding its placeholders") | |
| single = isinstance(text, str) | |
| prompts = [text] if single else list(text) | |
| expanded, codes, audio_out_offsets = self._expand_audio_out(prompts, audio_out) | |
| merged = self._merge_kwargs( | |
| self.valid_processor_kwargs, tokenizer_init_kwargs=self.tokenizer.init_kwargs, **kwargs | |
| ) | |
| return_tensors = merged["text_kwargs"].get("return_tensors") | |
| outputs = super().__call__(text=expanded[0] if single else expanded, audio=audio, **kwargs) | |
| self._check_audio_out_placeholders(outputs["input_ids"], codes.shape[0]) | |
| if "text_replacement_offsets" in outputs: | |
| # the shared expansion saw the text after the speech placeholders were repeated | |
| outputs["text_replacement_offsets"] = self._compose_replacement_offsets( | |
| prompts, audio_out_offsets, outputs["text_replacement_offsets"] | |
| ) | |
| outputs["audio_out_codes"] = self._as_return_tensors(codes, return_tensors) | |
| return outputs | |
| def _check_audio_out_placeholders(self, input_ids, num_frames: int) -> None: | |
| # truncation may have dropped placeholders the codes still cover | |
| rows = input_ids.tolist() if hasattr(input_ids, "tolist") else input_ids | |
| rows = [rows] if rows and isinstance(rows[0], int) else rows | |
| num_placeholders = sum(row.count(self.audio_out_token_id) for row in rows) | |
| if num_placeholders != num_frames: | |
| raise ValueError( | |
| f"Found {num_placeholders} {self.audio_out_token} tokens after tokenization for {num_frames} " | |
| "speech frames; disable truncation or shorten the prompt" | |
| ) | |
| def _as_return_tensors(codes: torch.Tensor, return_tensors): | |
| return BatchFeature({"codes": codes}, tensor_type=return_tensors)["codes"] | |
| def _rewrite_with_offsets(prompt: str, pattern: str, replace, kind: str) -> tuple[str, list[dict]]: | |
| """Rewrites `prompt` like `ProcessorMixin.get_text_with_replacements`, with the same offset records.""" | |
| pieces, row, last, offset = [], [], 0, 0 | |
| for match in re.finditer(pattern, prompt): | |
| start, end = match.span() | |
| replacement = replace(match) | |
| pieces.extend((prompt[last:start], replacement)) | |
| row.append( | |
| { | |
| "type": kind, | |
| "span": (start, end), | |
| "new_span": (start + offset, start + offset + len(replacement)), | |
| "text": match.group(), | |
| "replacement": replacement, | |
| } | |
| ) | |
| offset += len(replacement) - (end - start) | |
| last = end | |
| pieces.append(prompt[last:]) | |
| return "".join(pieces), row | |
| def _compose_replacement_offsets(prompts: list[str], first: list[list[dict]], second) -> list[list[dict]]: | |
| """The records of two successive rewrites (the caller's text A to B, then B to C) as one rewrite of A: an entry | |
| of the second that covers entries of the first absorbs them, so every entry spans the caller's text.""" | |
| second = second or [[] for _ in prompts] | |
| composed = [] | |
| for prompt, row_first, row_second in zip(prompts, first, second): | |
| def to_first(position, row_first=row_first): | |
| return position - sum( | |
| len(r["replacement"]) - (r["span"][1] - r["span"][0]) | |
| for r in row_first | |
| if r["new_span"][1] <= position | |
| ) | |
| mapped = [] | |
| for entry in row_second: | |
| start, end = to_first(entry["span"][0]), to_first(entry["span"][1]) | |
| mapped.append({**entry, "span": (start, end), "text": prompt[start:end]}) | |
| kept = [ | |
| r | |
| for r in row_first | |
| if not any(m["span"][0] <= r["span"][0] and r["span"][1] <= m["span"][1] for m in mapped) | |
| ] | |
| row, offset = [], 0 | |
| for entry in sorted(kept + mapped, key=lambda r: r["span"]): | |
| start, end = entry["span"] | |
| row.append({**entry, "new_span": (start + offset, start + offset + len(entry["replacement"]))}) | |
| offset += len(entry["replacement"]) - (end - start) | |
| composed.append(row) | |
| return composed | |
| def _expand_audio_out( | |
| self, prompts: list[str], audio_out: AudioInput | |
| ) -> tuple[list[str], torch.Tensor, list[list[dict]]]: | |
| if getattr(self, "audio_tokenizer", None) is None: | |
| raise ValueError("`audio_out` requires the processor to hold the codec as `audio_tokenizer`") | |
| clips = make_list_of_audio(audio_out) | |
| if sum(prompt.count(self.audio_out_token) for prompt in prompts) != len(clips): | |
| raise ValueError(f"The number of {self.audio_out_token} tokens in the text must match the number of clips") | |
| codes = [self.encode_audio(clip) for clip in clips] | |
| # the model ends speech with a frame of end-of-speech codes before the next text token; the prompt and the | |
| # training targets carry it the same way `generate(return_audio_eos=True)` does | |
| eos_frame = torch.full((1, codes[0].shape[1]), self.audio_eos_code, dtype=codes[0].dtype) | |
| codes = [torch.cat((frames, eos_frame)) for frames in codes] | |
| frame_counts = iter(code.shape[0] for code in codes) | |
| expanded, offsets = [], [] | |
| for prompt in prompts: | |
| prompt, row = self._rewrite_with_offsets( | |
| prompt, | |
| re.escape(self.audio_out_token), | |
| lambda match: self.audio_out_token * next(frame_counts), | |
| "audio_out", | |
| ) | |
| expanded.append(prompt) | |
| offsets.append(row) | |
| return expanded, torch.cat(codes), offsets | |
| def audio_eos_code(self) -> int: | |
| """The end-of-speech code: the first id after the codec's vocabulary.""" | |
| return math.prod(self.audio_tokenizer.config.fsq_levels) | |
| def encode_audio(self, audio) -> torch.Tensor: | |
| codec = self.audio_tokenizer | |
| waveform = torch.as_tensor(audio if torch.is_tensor(audio) else np.asarray(audio), dtype=torch.float32) | |
| # the quantizer rounds non-finite values to INT64_MIN, which would surface as codes | |
| if waveform.ndim != 1 or not torch.isfinite(waveform).all(): | |
| raise ValueError("`audio_out` clips must be mono waveforms of finite samples") | |
| # an offloaded codec keeps some weights on `meta`: send the clip to a device that holds weights, and the hooks | |
| # move it on from there | |
| device = next( | |
| (param.device for param in codec.parameters() if param.device.type != "meta"), torch.device("cpu") | |
| ) | |
| # the codec's return type follows its config's `return_dict` | |
| codes = codec.encode(waveform.to(device)[None], return_dict=True).audio_codes[0].T.cpu() | |
| # a compiled codec skips its latent check, and a non-finite latent rounds to INT64_MIN | |
| if codes.numel() and not 0 <= int(codes.min()) <= int(codes.max()) < self.audio_eos_code: | |
| raise ValueError("The audio overflows the codec; expected `audio_out` samples in [-1, 1]") | |
| return codes | |
| def validate_inputs(self, images=None, text=None, videos=None, audio=None, **kwargs): | |
| super().validate_inputs(images=images, text=text, videos=videos, audio=audio, **kwargs) | |
| if text is None: | |
| return | |
| prompts = [text] if isinstance(text, str) else text | |
| num_placeholders = sum(prompt.count(self.audio_token) for prompt in prompts) | |
| num_clips = 0 if audio is None else len(make_list_of_audio(audio)) | |
| if num_placeholders != num_clips: | |
| raise ValueError( | |
| f"Found {num_placeholders} {self.audio_token} tokens in the text but received {num_clips} clips" | |
| ) | |
| def _process_audio(self, audio: AudioInput, **kwargs): | |
| # the backend only serves `apply_chat_template`'s audio loading | |
| kwargs.pop("load_audio_backend", None) | |
| audio_inputs = self.feature_extractor(audio, **kwargs) | |
| lengths = np.asarray(audio_inputs["feature_attention_mask"]).sum(-1).tolist() | |
| audio_inputs["num_audio_tokens"] = [ | |
| self.feature_extractor.num_encoder_tokens(int(length)) for length in lengths | |
| ] | |
| audio_replacements = [self.replace_audio_token(audio_inputs, audio_idx=idx) for idx in range(len(lengths))] | |
| return audio_inputs, audio_replacements | |
| def replace_audio_token(self, audio_inputs: dict, audio_idx: int, **kwargs) -> str: | |
| return self.audio_token * audio_inputs["num_audio_tokens"][audio_idx] | |
| def unused_input_names(self) -> list[str]: | |
| return ["num_audio_tokens"] | |
| def model_input_names(self): | |
| tokenizer_input_names = self.tokenizer.model_input_names | |
| feature_extractor_input_names = self.feature_extractor.model_input_names | |
| return list(dict.fromkeys(tokenizer_input_names + feature_extractor_input_names + ["audio_out_codes"])) | |
| __all__ = ["Lfm3AudioProcessor"] | |