diff --git a/hoplite/agile/2_agile_modeling_v2.ipynb b/hoplite/agile/2_agile_modeling_v2.ipynb
index 3ba1131..ad6960d 100644
--- a/hoplite/agile/2_agile_modeling_v2.ipynb
+++ b/hoplite/agile/2_agile_modeling_v2.ipynb
@@ -10,15 +10,19 @@
       "source": [
         "#@title Imports. { vertical-output: true }\n",
         "\n",
-        "import numpy as np\n",
+        "import os\n",
+        "\n",
         "from matplotlib import pyplot as plt\n",
+        "import numpy as np\n",
         "\n",
         "from hoplite.agile import audio_loader\n",
         "from hoplite.agile import classifier\n",
         "from hoplite.agile import classifier_data\n",
         "from hoplite.agile import embedding_display\n",
+        "from hoplite.agile import source_info\n",
         "from hoplite.db  import brutalism\n",
         "from hoplite.db import score_functions\n",
+        "from hoplite.db  import search_results\n",
         "from hoplite.db import sqlite_usearch_impl\n",
         "from hoplite.zoo import model_configs\n"
       ]
@@ -40,13 +44,18 @@
         "\n",
         "db = sqlite_usearch_impl.SQLiteUsearchDB.create(db_path)\n",
         "db_model_config = db.get_metadata('model_config')\n",
-        "embed_config = db.get_metadata('embed_config')\n",
+        "embed_config = db.get_metadata('audio_sources')\n",
         "model_class = model_configs.MODEL_CLASS_MAP[db_model_config.model_key]\n",
         "embedding_model = model_class.from_config(db_model_config.model_config)\n",
-        "\n",
+        "audio_sources = source_info.AudioSources.from_config_dict(\n",
+        "    embed_config.audio_sources)\n",
+        "if hasattr(embedding_model, 'window_size_s'):\n",
+        "  window_size_s = embedding_model.window_size_s\n",
+        "else:\n",
+        "  window_size_s = 5.0\n",
         "audio_filepath_loader = audio_loader.make_filepath_loader(\n",
-        "    audio_globs=embed_config.audio_globs,\n",
-        "    window_size_s=embedding_model.window_size_s,\n",
+        "    audio_sources=audio_sources,\n",
+        "    window_size_s=window_size_s,\n",
         "    sample_rate_hz=embedding_model.sample_rate,\n",
         ")"
       ]
@@ -94,8 +103,6 @@
         "num_results = 50  #@param\n",
         "query_embedding = embedding_model.embed(\n",
         "    query.get_audio_window()).embeddings[0, 0]\n",
-        "#@markdown Number of (randomly selected) database entries to search over.\n",
-        "sample_size = 1_000_000  #@param\n",
         "\n",
         "#@markdown If checked, search for examples\n",
         "#@markdown near a particular target score.\n",
@@ -103,19 +110,28 @@
         "\n",
         "#@markdown When target sampling, target this score.\n",
         "target_score = -1.0  #@param\n",
-        "\n",
         "if not target_sampling:\n",
         "  target_score = None\n",
-        "score_fn = score_functions.get_score_fn('dot', target_score=target_score)\n",
-        "results, all_scores = brutalism.threaded_brute_search(\n",
-        "    db, query_embedding, num_results, score_fn=score_fn,\n",
-        "    sample_size=sample_size)\n",
         "\n",
-        "# TODO(tomdenton): Better histogram when target sampling.\n",
-        "_ = plt.hist(all_scores, bins=100)\n",
-        "hit_scores = [r.sort_score for r in results.search_results]\n",
-        "plt.scatter(hit_scores, np.zeros_like(hit_scores), marker='|',\n",
-        "            color='r', alpha=0.5)\n"
+        "#@markdown If True, search the full DB. Otherwise, use approximate\n",
+        "#@markdown nearest-neighbor search.\n",
+        "exact_search = False  #@param {type: 'boolean'}\n",
+        "\n",
+        "if exact_search:\n",
+        "  target_score = None\n",
+        "  score_fn = score_functions.get_score_fn('dot', target_score=target_score)\n",
+        "  results, all_scores = brutalism.threaded_brute_search(\n",
+        "      db, query_embedding, num_results, score_fn=score_fn)\n",
+        "  # TODO(tomdenton): Better histogram when target sampling.\n",
+        "  _ = plt.hist(all_scores, bins=100)\n",
+        "  hit_scores = [r.sort_score for r in results.search_results]\n",
+        "  plt.scatter(hit_scores, np.zeros_like(hit_scores), marker='|',\n",
+        "              color='r', alpha=0.5)\n",
+        "else:\n",
+        "  ann_matches = db.ui.search(query_embedding, count=num_results)\n",
+        "  results = search_results.TopKSearchResults(top_k=num_results)\n",
+        "  for k, d in zip(ann_matches.keys, ann_matches.distances):\n",
+        "    results.update(search_results.SearchResult(k, d))\n"
       ]
     },
     {
@@ -175,7 +191,7 @@
         "#@markdown Set of labels to classify. If None, auto-populated from the DB.\n",
         "target_labels = None  #@param\n",
         "\n",
-        "#@markdown Classifier traning params. These should not require tuning.\n",
+        "#@markdown Classifier traning hyperparams. These should not require tuning.\n",
         "learning_rate = 1e-3  #@param\n",
         "weak_neg_weight = 0.05  #@param\n",
         "l2_mu = 0.000  #@param\n",
@@ -196,13 +212,11 @@
         "    rng=np.random.default_rng(seed=5))\n",
         "print('Training for target labels : ')\n",
         "print(data_manager.get_target_labels())\n",
-        "params, eval_scores = classifier.train_linear_classifier(\n",
+        "linear_classifier, eval_scores = classifier.train_linear_classifier(\n",
         "    data_manager=data_manager,\n",
         "    learning_rate=learning_rate,\n",
         "    weak_neg_weight=weak_neg_weight,\n",
-        "    l2_mu=l2_mu,\n",
         "    num_train_steps=num_steps,\n",
-        "    loss_name=loss_fn_name,\n",
         ")\n",
         "print('\\n' + '-' * 80)\n",
         "top1 = eval_scores['top1_acc']\n",
@@ -210,7 +224,10 @@
         "rocauc = eval_scores['roc_auc']\n",
         "print(f'roc_auc    {rocauc:.3f}')\n",
         "cmap = eval_scores['cmap']\n",
-        "print(f'cmap       {cmap:.3f}')"
+        "print(f'cmap       {cmap:.3f}')\n",
+        "\n",
+        "# Save linear classifier.\n",
+        "linear_classifier.save(os.path.join(db_path, 'agile_classifier_v2.pt'))"
       ]
     },
     {
@@ -228,8 +245,8 @@
         "num_results = 50  #@param\n",
         "\n",
         "target_label_idx = data_manager.get_target_labels().index(target_label)\n",
-        "class_query = params['beta'][:, target_label_idx]\n",
-        "bias = params['beta_bias'][target_label_idx]\n",
+        "class_query = linear_classifier.beta[:, target_label_idx]\n",
+        "bias = linear_classifier.beta_bias[target_label_idx]\n",
         "\n",
         "#@markdown Number of (randomly selected) database entries to search over.\n",
         "sample_size = 1_000_000  #@param\n",
@@ -289,6 +306,26 @@
         "print('\\nnew_lbls: ', new_lbls)\n",
         "print('\\nprev_lbls: ', prev_lbls)"
       ]
+    },
+    {
+      "cell_type": "code",
+      "execution_count": null,
+      "metadata": {
+        "id": "kBH-2kz4SaS2"
+      },
+      "outputs": [],
+      "source": [
+        "#@title Run inference with trained classifier. { vertical-output: true }\n",
+        "\n",
+        "output_csv_filepath = ''  #@param {type:'string'}\n",
+        "logit_threshold = 1.0  #@param\n",
+        "# Set labels to a tuple of desired labels if you want to run inference on a\n",
+        "# subset of the labels.\n",
+        "labels = None  #@param\n",
+        "\n",
+        "classifier.write_inference_csv(\n",
+        "    linear_classifier, db, output_csv_filepath, logit_threshold, labels=labels)\n"
+      ]
     }
   ],
   "metadata": {
diff --git a/hoplite/agile/audio_loader.py b/hoplite/agile/audio_loader.py
index 10224f0..365fd92 100644
--- a/hoplite/agile/audio_loader.py
+++ b/hoplite/agile/audio_loader.py
@@ -20,11 +20,12 @@
 
 from etils import epath
 from hoplite import audio_io
+from hoplite.agile import source_info
 import numpy as np
 
 
 def make_filepath_loader(
-    audio_globs: dict[str, tuple[str, str]],
+    audio_sources: source_info.AudioSources,
     sample_rate_hz: int = 32000,
     window_size_s: float = 5.0,
     dtype: str = 'float32',
@@ -34,8 +35,7 @@ def make_filepath_loader(
   Note that if multiple globs match a given source ID, the first match is used.
 
   Args:
-    audio_globs: Mapping from dataset name to pairs of `(root directory, file
-      glob)`. (See `embed.EmbedConfig` for details.)
+    audio_sources: Embedding audio sources.
     sample_rate_hz: Sample rate of the audio.
     window_size_s: Window size of the audio.
     dtype: Data type of the audio.
@@ -49,8 +49,8 @@ def make_filepath_loader(
 
   def loader(source_id: str, offset_s: float) -> np.ndarray:
     found_path = None
-    for base_path, _ in audio_globs.values():
-      path = epath.Path(base_path) / source_id
+    for audio_source in audio_sources.audio_globs:
+      path = epath.Path(audio_source.base_path) / source_id
       if path.exists():
         found_path = path
         break
diff --git a/hoplite/agile/classifier.py b/hoplite/agile/classifier.py
index f1f4edc..71dc763 100644
--- a/hoplite/agile/classifier.py
+++ b/hoplite/agile/classifier.py
@@ -15,15 +15,64 @@
 
 """Functions for training and applying a linear classifier."""
 
-from typing import Any
+import base64
+import dataclasses
+import json
+from typing import Any, Sequence
 
 from hoplite.agile import classifier_data
 from hoplite.agile import metrics
+from hoplite.db import interface as db_interface
+from hoplite.taxonomy import namespace
+from ml_collections import config_dict
 import numpy as np
 import tensorflow as tf
 import tqdm
 
 
+@dataclasses.dataclass
+class LinearClassifier:
+  """Wrapper for linear classifier params and metadata."""
+
+  beta: np.ndarray
+  beta_bias: np.ndarray
+  classes: tuple[str, ...]
+  embedding_model_config: Any
+
+  def __call__(self, embeddings: np.ndarray):
+    return np.dot(embeddings, self.beta) + self.beta_bias
+
+  def save(self, path: str):
+    """Save the classifier to a path."""
+    cfg = config_dict.ConfigDict()
+    cfg.model_config = self.embedding_model_config
+    cfg.classes = self.classes
+    # Convert numpy arrays to base64 encoded blobs.
+    beta_bytes = base64.b64encode(np.float32(self.beta).tobytes()).decode(
+        'ascii'
+    )
+    beta_bias_bytes = base64.b64encode(
+        np.float32(self.beta_bias).tobytes()
+    ).decode('ascii')
+    cfg.beta = beta_bytes
+    cfg.beta_bias = beta_bias_bytes
+    with open(path, 'w') as f:
+      f.write(cfg.to_json())
+
+  @classmethod
+  def load(cls, path: str):
+    """Load a classifier from a path."""
+    with open(path, 'r') as f:
+      cfg_json = json.loads(f.read())
+      cfg = config_dict.ConfigDict(cfg_json)
+    classes = cfg.classes
+    beta = np.frombuffer(base64.b64decode(cfg.beta), dtype=np.float32)
+    beta = np.reshape(beta, (-1, len(classes)))
+    beta_bias = np.frombuffer(base64.b64decode(cfg.beta_bias), dtype=np.float32)
+    embedding_model_config = cfg.model_config
+    return cls(beta, beta_bias, classes, embedding_model_config)
+
+
 def get_linear_model(embedding_dim: int, num_classes: int) -> tf.keras.Model:
   """Create a simple linear Keras model."""
   model = tf.keras.Sequential([
@@ -43,12 +92,28 @@ def bce_loss(
   y_true = tf.cast(y_true, dtype=logits.dtype)
   log_p = tf.math.log_sigmoid(logits)
   log_not_p = tf.math.log_sigmoid(-logits)
-  raw_bce = -y_true * log_p + (1.0 - y_true) * log_not_p
+  # optax sigmoid_binary_cross_entropy:
+  # -labels * log_p - (1.0 - labels) * log_not_p
+  raw_bce = -y_true * log_p - (1.0 - y_true) * log_not_p
   is_labeled_mask = tf.cast(is_labeled_mask, dtype=logits.dtype)
   weights = (1.0 - is_labeled_mask) * weak_neg_weight + is_labeled_mask
   return tf.reduce_mean(raw_bce * weights)
 
 
+def hinge_loss(
+    y_true: tf.Tensor,
+    logits: tf.Tensor,
+    is_labeled_mask: tf.Tensor,
+    weak_neg_weight: float,
+) -> tf.Tensor:
+  """Weighted SVM hinge loss."""
+  # Convert multihot to +/- 1 labels.
+  y_true = 2 * y_true - 1
+  weights = (1.0 - is_labeled_mask) * weak_neg_weight + is_labeled_mask
+  raw_hinge_loss = tf.maximum(0, 1 - y_true * logits)
+  return tf.reduce_mean(raw_hinge_loss * weights)
+
+
 def infer(params, embeddings: np.ndarray):
   """Apply the model to embeddings."""
   return np.dot(embeddings, params['beta']) + params['beta_bias']
@@ -105,19 +170,26 @@ def train_linear_classifier(
     learning_rate: float,
     weak_neg_weight: float,
     num_train_steps: int,
-):
+    loss: str = 'bce',
+) -> tuple[LinearClassifier, dict[str, float]]:
   """Train a linear classifier."""
   embedding_dim = data_manager.db.embedding_dimension()
   num_classes = len(data_manager.get_target_labels())
   lin_model = get_linear_model(embedding_dim, num_classes)
   optimizer = tf.keras.optimizers.Adam(learning_rate=learning_rate)
   lin_model.compile(optimizer=optimizer, loss='binary_crossentropy')
+  if loss == 'hinge':
+    loss_fn = hinge_loss
+  elif loss == 'bce':
+    loss_fn = bce_loss
+  else:
+    raise ValueError(f'Unknown loss: {loss}')
 
   @tf.function
   def train_step(y_true, embeddings, is_labeled_mask):
     with tf.GradientTape() as tape:
       logits = lin_model(embeddings, training=True)
-      loss = bce_loss(y_true, logits, is_labeled_mask, weak_neg_weight)
+      loss = loss_fn(y_true, logits, is_labeled_mask, weak_neg_weight)
       loss = tf.reduce_mean(loss)
     grads = tape.gradient(loss, lin_model.trainable_variables)
     optimizer.apply_gradients(zip(grads, lin_model.trainable_variables))
@@ -147,4 +219,61 @@ def train_step(y_true, embeddings, is_labeled_mask):
       'beta_bias': lin_model.get_weights()[1],
   }
   eval_scores = eval_classifier(params, data_manager, eval_idxes)
-  return params, eval_scores
+
+  model_config = data_manager.db.get_metadata('model_config')
+  linear_classifier = LinearClassifier(
+      beta=params['beta'],
+      beta_bias=params['beta_bias'],
+      classes=data_manager.get_target_labels(),
+      embedding_model_config=model_config,
+  )
+  return linear_classifier, eval_scores
+
+
+def write_inference_csv(
+    linear_classifier: LinearClassifier,
+    db: db_interface.HopliteDBInterface,
+    output_filepath: str,
+    threshold: float,
+    labels: Sequence[str] | None = None,
+):
+  """Write a CSV for all audio windows with logits above a threshold.
+
+  Args:
+    params: The parameters of the linear classifier.
+    class_list: The class list of labels associated with the classifier.
+    db: HopliteDBInterface to read embeddings from.
+    output_filepath: Path to write the CSV to.
+    threshold: Logits must be above this value to be written.
+    labels: If provided, only write logits for these labels. If None, write
+      logits for all labels.
+
+  Returns:
+    None
+  """
+  idxes = db.get_embedding_ids()
+  if labels is None:
+    labels = linear_classifier.classes
+  label_ids = {cl: i for i, cl in enumerate(linear_classifier.classes)}
+  target_label_ids = np.array([label_ids[l] for l in labels])
+  logits_fn = lambda emb: linear_classifier(emb)[target_label_ids]
+  detection_count = 0
+  with open(output_filepath, 'w') as f:
+    f.write('idx,dataset_name,source_id,offset,label,logits\n')
+    for idx in tqdm.tqdm(idxes):
+      source = db.get_embedding_source(idx)
+      emb = db.get_embedding(idx)
+      logits = logits_fn(emb)
+      for a in np.argwhere(logits > threshold):
+        lbl = labels[a[0]]
+        row = [
+            idx,
+            source.dataset_name,
+            source.source_id,
+            source.offsets[0],
+            lbl,
+            logits[a],
+        ]
+        f.write(','.join(map(str, row)) + '\n')
+        detection_count += 1
+  print(f'Wrote {detection_count} detections to {output_filepath}')
diff --git a/hoplite/agile/tests/classifier_test.py b/hoplite/agile/tests/classifier_test.py
new file mode 100644
index 0000000..c3b4313
--- /dev/null
+++ b/hoplite/agile/tests/classifier_test.py
@@ -0,0 +1,74 @@
+# coding=utf-8
+# Copyright 2024 The Perch Authors.
+#
+# 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.
+
+"""Tests for linear classifier implementation."""
+
+import os
+import tempfile
+
+from hoplite.agile import classifier
+from ml_collections import config_dict
+import numpy as np
+
+from absl.testing import absltest
+
+
+class ClassifierTest(absltest.TestCase):
+
+  def setUp(self):
+    super().setUp()
+    # `self.create_tempdir()` raises an UnparsedFlagAccessError, which is why
+    # we use `tempdir` directly.
+    self.tempdir = tempfile.mkdtemp()
+
+  def _make_linear_classifier(self, embedding_dim, classes):
+    np.random.seed(1234)
+    beta = np.float32(np.random.normal(size=(embedding_dim, len(classes))))
+    beta_bias = np.float32(np.random.normal(size=(len(classes),)))
+    embedding_model_config = config_dict.ConfigDict({
+        'model_name': 'nelson',
+    })
+    return classifier.LinearClassifier(
+        beta, beta_bias, classes, embedding_model_config
+    )
+
+  def test_call_linear_classifier(self):
+    embedding_dim = 8
+    classes = ('a', 'b', 'c')
+    classy = self._make_linear_classifier(embedding_dim, classes)
+
+    batch_embeddings = np.random.normal(size=(10, embedding_dim))
+    predictions = classy(batch_embeddings)
+    self.assertEqual(predictions.shape, (10, len(classes)))
+
+    single_embedding = np.random.normal(size=(embedding_dim,))
+    predictions = classy(single_embedding)
+    self.assertEqual(predictions.shape, (len(classes),))
+
+  def test_save_load_linear_classifier(self):
+    embedding_dim = 8
+    classes = ('a', 'b', 'c')
+    classy = self._make_linear_classifier(embedding_dim, classes)
+    classy_path = os.path.join(self.tempdir, 'classifier.json')
+    classy.save(classy_path)
+    classy_loaded = classifier.LinearClassifier.load(classy_path)
+    np.testing.assert_allclose(classy_loaded.beta, classy.beta)
+    np.testing.assert_allclose(classy_loaded.beta_bias, classy.beta_bias)
+    self.assertSequenceEqual(classy_loaded.classes, classy.classes)
+    self.assertEqual(classy_loaded.embedding_model_config.model_name, 'nelson')
+
+
+if __name__ == '__main__':
+  absltest.main()
diff --git a/hoplite/agile/tests/embedding_display_test.py b/hoplite/agile/tests/embedding_display_test.py
index 98660a5..67692db 100644
--- a/hoplite/agile/tests/embedding_display_test.py
+++ b/hoplite/agile/tests/embedding_display_test.py
@@ -22,6 +22,7 @@
 
 from hoplite.agile import audio_loader
 from hoplite.agile import embedding_display
+from hoplite.agile import source_info
 from hoplite.agile.tests import test_utils
 from hoplite.db import interface
 import IPython
@@ -170,11 +171,14 @@ def test_embedding_display_group(self):
         sample_rate_hz=sample_rate_hz,
     )
 
-    audio_globs = {
-        'test_dataset': (self.tempdir, '*/*.wav'),
-    }
+    audio_source = source_info.AudioSourceConfig(
+        dataset_name='test_dataset',
+        base_path=self.tempdir,
+        file_glob='*/*.wav',
+    )
+    audio_sources = source_info.AudioSources((audio_source,))
     filepath_audio_loader = audio_loader.make_filepath_loader(
-        audio_globs, sample_rate_hz=sample_rate_hz, window_size_s=1.0
+        audio_sources, sample_rate_hz=sample_rate_hz, window_size_s=1.0
     )
     group = embedding_display.EmbeddingDisplayGroup.create(
         members=[member0, member1],
diff --git a/hoplite/audio_io.py b/hoplite/audio_io.py
index e8dd122..88591d9 100644
--- a/hoplite/audio_io.py
+++ b/hoplite/audio_io.py
@@ -115,7 +115,7 @@ def load_audio_window_soundfile(
   with epath.Path(filepath).open('rb') as f:
     sf = soundfile.SoundFile(f)
     if offset_s > 0:
-      offset = int(offset_s * sf.samplerate)
+      offset = int(np.float32(offset_s) * sf.samplerate)
       sf.seek(offset)
     if window_size_s < 0:
       a = sf.read()