diff --git a/lib/voice.py b/lib/voice.py
new file mode 100644
index 0000000..163fac4
--- /dev/null
+++ b/lib/voice.py
@@ -0,0 +1,36 @@
+"""Resolve a ComfyUI AUDIO input or string path into a voice-reference dict."""
+
+import logging
+import os
+from typing import Optional
+
+from lib.audio import audio_dict_to_wav
+
+log = logging.getLogger(__name__)
+
+
+def build_voice_reference(
+    audio: Optional[dict],
+    audio_path: str,
+    temp_dir: str,
+) -> dict:
+    """Return a voice-reference container.
+
+    Priority:
+      1. If `audio` is set, write it to a temp WAV and use that path.
+         If `audio_path` is also set, log a warning and ignore it.
+      2. Else if `audio_path` is non-empty, validate the path exists and use it.
+      3. Else return source="none" / path=None (default voice).
+    """
+    if audio is not None:
+        if audio_path:
+            log.warning("Both audio and audio_path provided; ignoring audio_path=%r", audio_path)
+        path = audio_dict_to_wav(audio, dest_dir=temp_dir)
+        return {"path": path, "source": "audio"}
+
+    if audio_path:
+        if not os.path.isfile(audio_path):
+            raise FileNotFoundError(f"Voice reference audio not found: {audio_path}")
+        return {"path": audio_path, "source": "path"}
+
+    return {"path": None, "source": "none"}
diff --git a/tests/test_voice.py b/tests/test_voice.py
new file mode 100644
index 0000000..66f2898
--- /dev/null
+++ b/tests/test_voice.py
@@ -0,0 +1,44 @@
+import os
+import pytest
+from lib.voice import build_voice_reference
+
+
+def test_no_inputs_returns_none_source(tmp_path):
+    result = build_voice_reference(audio=None, audio_path="", temp_dir=str(tmp_path))
+    assert result == {"path": None, "source": "none"}
+
+
+def test_audio_path_only(tmp_path, sample_comfy_audio):
+    # Write a fake wav so the path exists
+    import torchaudio
+    wav_path = tmp_path / "ref.wav"
+    torchaudio.save(str(wav_path), sample_comfy_audio["waveform"][0], sample_comfy_audio["sample_rate"])
+    result = build_voice_reference(audio=None, audio_path=str(wav_path), temp_dir=str(tmp_path))
+    assert result["source"] == "path"
+    assert result["path"] == str(wav_path)
+
+
+def test_audio_path_missing_raises(tmp_path):
+    with pytest.raises(FileNotFoundError):
+        build_voice_reference(audio=None, audio_path=str(tmp_path / "nope.wav"), temp_dir=str(tmp_path))
+
+
+def test_audio_input_writes_temp_wav(tmp_path, sample_comfy_audio):
+    result = build_voice_reference(audio=sample_comfy_audio, audio_path="", temp_dir=str(tmp_path))
+    assert result["source"] == "audio"
+    assert os.path.isfile(result["path"])
+    assert result["path"].startswith(str(tmp_path))
+
+
+def test_audio_wins_over_path(tmp_path, sample_comfy_audio, caplog):
+    import torchaudio
+    wav_path = tmp_path / "ref.wav"
+    torchaudio.save(str(wav_path), sample_comfy_audio["waveform"][0], sample_comfy_audio["sample_rate"])
+    result = build_voice_reference(
+        audio=sample_comfy_audio,
+        audio_path=str(wav_path),
+        temp_dir=str(tmp_path),
+    )
+    assert result["source"] == "audio"
+    assert result["path"] != str(wav_path)
+    assert any("audio_path" in rec.message for rec in caplog.records)