Encodec (#991)

* initial encodec

* works

* nits

* use fast group norm

* fix for rnn layer

* fix mlx version

* use custom LSTM kernel

* audio encodec

* fix example, support batched inference

* nits

encodec/convert.py

@@ -0,0 +1,213 @@
+# Copyright © 2024 Apple Inc.
+
+import argparse
+import json
+from pathlib import Path
+from textwrap import dedent
+from types import SimpleNamespace
+from typing import Any, Dict, Union
+
+import mlx.core as mx
+import mlx.nn as nn
+from huggingface_hub import snapshot_download
+from mlx.utils import tree_flatten
+
+import encodec
+
+
+def fetch_from_hub(hf_repo: str) -> Path:
+    model_path = Path(
+        snapshot_download(
+            repo_id=hf_repo,
+            allow_patterns=["*.json", "*.safetensors"],
+        )
+    )
+    return model_path
+
+
+def upload_to_hub(path: str, upload_repo: str, hf_path: str):
+    """
+    Uploads the model to Hugging Face hub.
+
+    Args:
+        path (str): Local path to the model.
+        upload_repo (str): Name of the HF repo to upload to.
+        hf_path (str): Path to the original Hugging Face model.
+    """
+    import os
+
+    from huggingface_hub import HfApi, ModelCard, logging
+
+    content = dedent(
+        f"""
+        ---
+        language: en
+        license: other
+        library: mlx
+        tags:
+        - mlx
+        ---
+
+        The Model [{upload_repo}](https://huggingface.co/{upload_repo}) was
+        converted to MLX format from
+        [{hf_path}](https://huggingface.co/{hf_path}).
+
+        This model is intended to be used with the [EnCodec MLX
+        example](https://github.com/ml-explore/mlx-examples/tree/main/encodec).
+        """
+    )
+
+    card = ModelCard(content)
+    card.save(os.path.join(path, "README.md"))
+
+    logging.set_verbosity_info()
+
+    api = HfApi()
+    api.create_repo(repo_id=upload_repo, exist_ok=True)
+    api.upload_folder(
+        folder_path=path,
+        repo_id=upload_repo,
+        repo_type="model",
+        multi_commits=True,
+        multi_commits_verbose=True,
+    )
+    print(f"Upload successful, go to https://huggingface.co/{upload_repo} for details.")
+
+
+def save_weights(save_path: Union[str, Path], weights: Dict[str, Any]) -> None:
+    if isinstance(save_path, str):
+        save_path = Path(save_path)
+    save_path.mkdir(parents=True, exist_ok=True)
+
+    total_size = sum(v.nbytes for v in weights.values())
+    index_data = {"metadata": {"total_size": total_size}, "weight_map": {}}
+    mx.save_safetensors(
+        str(save_path / "model.safetensors"), weights, metadata={"format": "mlx"}
+    )
+
+    for weight_name in weights.keys():
+        index_data["weight_map"][weight_name] = "model.safetensors"
+
+    index_data["weight_map"] = {
+        k: index_data["weight_map"][k] for k in sorted(index_data["weight_map"])
+    }
+
+    with open(save_path / "model.safetensors.index.json", "w") as f:
+        json.dump(index_data, f, indent=4)
+
+
+def save_config(
+    config: dict,
+    config_path: Union[str, Path],
+) -> None:
+    """Save the model configuration to the ``config_path``.
+
+    The final configuration will be sorted before saving for better readability.
+
+    Args:
+        config (dict): The model configuration.
+        config_path (Union[str, Path]): Model configuration file path.
+    """
+    # Clean unused keys
+    config.pop("_name_or_path", None)
+
+    # sort the config for better readability
+    config = dict(sorted(config.items()))
+
+    # write the updated config to the config_path (if provided)
+    with open(config_path, "w") as fid:
+        json.dump(config, fid, indent=4)
+
+
+def convert(
+    upload: bool,
+    model: str,
+    dtype: str = None,
+):
+    hf_repo = f"facebook/encodec_{model}"
+    mlx_repo = f"mlx-community/encodec-{model}-{dtype}"
+    path = fetch_from_hub(hf_repo)
+    save_path = Path("mlx_models")
+
+    weights = mx.load(str(Path(path) / "model.safetensors"))
+
+    with open(path / "config.json", "r") as fid:
+        config = SimpleNamespace(**json.load(fid))
+
+    model = encodec.EncodecModel(config)
+
+    new_weights = {}
+    for k, v in weights.items():
+        basename, pname = k.rsplit(".", 1)
+        if pname == "weight_v":
+            g = weights[basename + ".weight_g"]
+            v = g * (v / mx.linalg.norm(v, axis=(1, 2), keepdims=True))
+            k = basename + ".weight"
+        elif pname in ["weight_g", "embed_avg", "cluster_size", "inited"]:
+            continue
+        elif "lstm" in basename:
+            w_or_b, ih_or_hh, ln = pname.split("_")
+            if w_or_b == "weight":
+                new_pname = "Wx" if ih_or_hh == "ih" else "Wh"
+            elif w_or_b == "bias" and ih_or_hh == "ih":
+                continue
+            else:
+                v = v + weights[k.replace("_hh_", "_ih_")]
+                new_pname = "bias"
+            k = basename + "." + ln[1:] + "." + new_pname
+        if "conv.weight" in k:
+            # Possibly a transposed conv which has a different order
+            if "decoder" in k:
+                ln = int(k.split(".")[2])
+                if "conv" in model.decoder.layers[ln] and isinstance(
+                    model.decoder.layers[ln].conv, nn.ConvTranspose1d
+                ):
+                    v = mx.moveaxis(v, 0, 2)
+                else:
+                    v = mx.moveaxis(v, 1, 2)
+            else:
+                v = mx.moveaxis(v, 1, 2)
+
+        new_weights[k] = v
+    weights = new_weights
+
+    model.load_weights(list(weights.items()))
+
+    if dtype is not None:
+        t = getattr(mx, dtype)
+        weights = {k: v.astype(t) for k, v in weights.items()}
+
+    if isinstance(save_path, str):
+        save_path = Path(save_path)
+
+    save_weights(save_path, weights)
+
+    save_config(vars(config), config_path=save_path / "config.json")
+
+    if upload:
+        upload_to_hub(save_path, mlx_repo, hf_repo)
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description="Convert EnCodec weights to MLX.")
+    parser.add_argument(
+        "--model",
+        type=str,
+        default="48khz",
+        help="",
+        choices=["24khz", "32khz", "48khz"],
+    )
+    parser.add_argument(
+        "--upload",
+        action="store_true",
+        help="Upload the weights to Hugging Face.",
+    )
+    parser.add_argument(
+        "--dtype",
+        type=str,
+        help="Data type to convert the model to.",
+        default="float32",
+        choices=["float32", "bfloat16", "float16"],
+    )
+    args = parser.parse_args()
+    convert(upload=args.upload, model=args.model, dtype=args.dtype)