arabic-native-classifier / scripts /make_predictions.py
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Fix model architecture: add PCA transform (2051->256d) to match training pipeline
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"""
Run inference on test CSV: download audio, chunk, embed with Wav2Vec (middle layers), classify.
Arabic Native vs Non-Native. Uses language-agnostic middle-layer embeddings.
"""
import os
import sys
import pandas as pd
import numpy as np
import torch
import librosa
import requests
import io
from transformers import Wav2Vec2Model, AutoFeatureExtractor
from tqdm import tqdm
from sklearn.metrics import (
accuracy_score,
f1_score,
precision_score,
recall_score,
confusion_matrix,
)
# Import shared classifier (same architecture as training)
sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
from model import NativityClassifier
from extract_embeddings import get_mfcc_from_audio, get_pitch_stats, PROSODY_EMBED_DIM, EMBED_DIM_WITH_MFCC
# -----------------------------------------------------------------------------
# Config
# -----------------------------------------------------------------------------
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
model_path = "models/nativity_model.pth"
input_csv = "manifests/test_data.csv"
output_csv = "final_predictions.csv"
EMBED_DIM_FILE = "manifests/embedding_dim.txt"
# Model arch must match train_classifier_compare / model.py
HIDDEN_DIMS = (256, 128) # Must match train_classifier_compare.py
DROPOUT = 0.4
PCA_COMPONENTS = 256
PCA_PATH = "models/pca_transform.pkl"
EVAL_THRESHOLD_DEFAULT = 0.35
BEST_THRESHOLD_PATH = "models/best_threshold.txt"
PROSODY_LAYERS = (4, 6, 8, 10) # must match extract_embeddings.py (prosody-focused)
# Embedding dim: 2051 (prosody) or 2090 (prosody+MFCC)
embedding_dim = PROSODY_EMBED_DIM
if os.path.isfile(EMBED_DIM_FILE):
with open(EMBED_DIM_FILE) as f:
embedding_dim = int(f.read().strip())
# Use validation-picked threshold if available (from train_classifier_compare.py)
if os.path.isfile(BEST_THRESHOLD_PATH):
with open(BEST_THRESHOLD_PATH) as f:
EVAL_THRESHOLD = float(f.read().strip())
else:
EVAL_THRESHOLD = EVAL_THRESHOLD_DEFAULT
# -----------------------------------------------------------------------------
# Load models
# -----------------------------------------------------------------------------
import joblib
model_name = "facebook/wav2vec2-large-xlsr-53"
feature_extractor = AutoFeatureExtractor.from_pretrained(model_name)
wav2vec = Wav2Vec2Model.from_pretrained(model_name).to(device)
wav2vec.eval()
pca = joblib.load(PCA_PATH)
classifier = NativityClassifier(
input_dim=PCA_COMPONENTS,
hidden_dims=HIDDEN_DIMS,
output_dim=2,
dropout=DROPOUT,
).to(device)
classifier.load_state_dict(torch.load(model_path, map_location=device))
classifier.eval()
def get_embedding(audio_np, embed_dim=None):
"""Prosody embedding: mean+std+pitch (2051-d) or +MFCC (2090-d); L2 norm to match training."""
if embed_dim is None:
embed_dim = embedding_dim
with torch.no_grad():
input_values = feature_extractor(
audio_np, return_tensors="pt", sampling_rate=16000
).input_values.to(device)
outputs = wav2vec(input_values, output_hidden_states=True)
h = outputs.hidden_states
num_layers = len(h) - 1
layer_idx = [min(max(l, 1), num_layers) for l in PROSODY_LAYERS]
embs = [h[i] for i in layer_idx]
time_seq = torch.stack(embs, dim=0).mean(dim=0).squeeze(0) # (T, 1024)
emb_mean = time_seq.mean(dim=0).cpu().numpy().astype(np.float32)
emb_std = time_seq.std(dim=0).cpu().numpy().astype(np.float32)
np.nan_to_num(emb_std, copy=False, nan=0.0, posinf=0.0, neginf=0.0)
pitch = get_pitch_stats(audio_np, sr=16000)
out = np.concatenate([emb_mean, emb_std, pitch]).astype(np.float32)
if embed_dim == EMBED_DIM_WITH_MFCC:
mfcc_39 = get_mfcc_from_audio(audio_np, sr=16000)
out = np.concatenate([out, mfcc_39]).astype(np.float32)
n = np.linalg.norm(out)
if n > 1e-8:
out = out / n
out = out.reshape(1, -1)
# Apply PCA to match training pipeline (2051-d -> 256-d)
out = pca.transform(out).astype(np.float32)
return torch.tensor(out, dtype=torch.float32, device=device)
def process_file_and_predict(url):
"""
Download, chunk (10s), embed each chunk, then aggregate with confidence-weighted voting.
Returns (label_str, confidence).
"""
try:
response = requests.get(url, timeout=15)
response.raise_for_status()
raw = response.content
if not raw or len(raw) < 100:
return "Error", 0.0
ct = (response.headers.get("Content-Type") or "").lower()
if "text/html" in ct or raw.lstrip()[:50].startswith(b"<!") or raw.lstrip()[:20].startswith(b"<?"):
return "Error", 0.0
audio_bytes = io.BytesIO(raw)
y, sr = librosa.load(audio_bytes, sr=16000, mono=True)
except Exception:
return "Error", 0.0
chunk_size = 160000 # 10 sec at 16 kHz
chunks = [
y[i : i + chunk_size]
for i in range(0, len(y), chunk_size)
if len(y[i : i + chunk_size]) == chunk_size
]
if not chunks:
return "Error", 0.0
chunk_preds = [] # 0 = Native, 1 = Non-Native
chunk_confs = [] # probability of predicted class
with torch.no_grad():
for chunk in chunks:
emb = get_embedding(chunk, embed_dim=embedding_dim)
logits = classifier(emb)
probs = torch.softmax(logits, dim=1)
p1 = probs[0, 1].item()
pred = 1 if p1 >= EVAL_THRESHOLD else 0
conf = p1 if pred == 1 else (1.0 - p1)
chunk_preds.append(pred)
chunk_confs.append(conf)
# Confidence-weighted voting: weight each chunk by its confidence
weights = np.array(chunk_confs, dtype=np.float64)
weights = weights / (weights.sum() + 1e-10)
weighted_score = np.sum(np.array(chunk_preds) * weights)
final_label = "Non-Native" if weighted_score >= EVAL_THRESHOLD else "Native"
# Final confidence = weighted average of confidences (or max)
final_conf = float(np.average(chunk_confs, weights=weights))
return final_label, final_conf
def main():
df = pd.read_csv(input_csv)
results = []
print(f"Predicting for {len(df)} files (device={device})...")
for _, row in tqdm(df.iterrows(), total=len(df)):
label, conf = process_file_and_predict(row["audio_url"])
results.append({
"dp_id": row["dp_id"],
"prediction": label,
"confidence_score": round(conf, 4),
})
out_df = pd.DataFrame(results)
out_df.to_csv(output_csv, index=False)
n_ok = (out_df["prediction"] != "Error").sum()
n_fail = len(out_df) - n_ok
print(f"Done. Saved to {output_csv} ({n_ok} predicted, {n_fail} failed to load)")
# If ground-truth labels exist (nativity_status), print test metrics like validation
if "nativity_status" in df.columns:
mask = out_df["prediction"] != "Error"
y_true_str = df.loc[mask, "nativity_status"].values
y_pred_str = out_df.loc[mask, "prediction"].values
map_fn = lambda s: 1 if s == "Non-Native" else 0
y_true = np.array([map_fn(s) for s in y_true_str])
y_pred = np.array([map_fn(s) for s in y_pred_str])
acc = accuracy_score(y_true, y_pred)
f1 = f1_score(y_true, y_pred, average="macro", zero_division=0)
prec = precision_score(y_true, y_pred, average="macro", zero_division=0)
rec = recall_score(y_true, y_pred, average="macro", zero_division=0)
cm = confusion_matrix(y_true, y_pred)
print("\nTest metrics (from test_data.csv, using nativity_status):")
print(f" Accuracy: {acc:.4f}")
print(f" F1 macro: {f1:.4f}")
print(f" Precision: {prec:.4f}")
print(f" Recall: {rec:.4f}")
print(" Confusion matrix (rows=true, cols=pred):")
print(f" {cm}")
print(" (Native=0, Non-Native=1)")
if __name__ == "__main__":
main()