feat(music-lab): 영상 인코딩을 Windows GPU 서버로 오프로드

- pipeline/video.py 재작성: subprocess.run 제거, httpx로 Windows /encode_video 호출
- Windows 서버 다운 시 즉시 VideoGenerationError (NAS 로컬 폴백 X — 의도적 결정)
- /app/data/* → /volume1/docker/webpage/data/* 경로 변환 (_container_to_nas)
- 테스트는 respx mock 기반으로 교체 (6개)

music-lab/tests/test_video_thumb.py

@@ -3,6 +3,10 @@ import pytest
 from unittest.mock import patch, MagicMock
 from app.pipeline import video, thumb, storage
 
+import respx
+import httpx
+from httpx import Response
+
 
 @pytest.fixture
 def tmp_storage(monkeypatch, tmp_path):
@@ -17,31 +21,6 @@ def tmp_storage(monkeypatch, tmp_path):
     return tmp_path
 
 
-@patch("subprocess.run")
-def test_generate_video_calls_ffmpeg(mock_run, tmp_storage):
-    mock_run.return_value = MagicMock(returncode=0, stderr="")
-    out = video.generate(pipeline_id=50, audio_path=str(tmp_storage / "audio.mp3"),
-                         cover_path=str(tmp_storage / "50" / "cover.jpg"),
-                         genre="lo-fi", duration_sec=120, resolution="1920x1080",
-                         style="visualizer")
-    assert out["url"].endswith("/50/video.mp4")
-    assert out["used_fallback"] is False
-    args = mock_run.call_args[0][0]
-    assert args[0] == "ffmpeg"
-    assert "-i" in args
-    assert "showwaves" in " ".join(args)
-
-
-@patch("subprocess.run")
-def test_generate_video_failure_marks_failed(mock_run, tmp_storage):
-    mock_run.return_value = MagicMock(returncode=1, stderr="bad codec")
-    with pytest.raises(video.VideoGenerationError):
-        video.generate(pipeline_id=51, audio_path=str(tmp_storage / "audio.mp3"),
-                        cover_path=str(tmp_storage / "50" / "cover.jpg"),
-                        genre="lo-fi", duration_sec=120, resolution="1920x1080",
-                        style="visualizer")
-
-
 @patch("subprocess.run")
 def test_thumb_extracts_frame(mock_run, tmp_storage):
     mock_run.return_value = MagicMock(returncode=0, stderr="")
@@ -64,3 +43,90 @@ def test_thumb_failure_raises(mock_run, tmp_storage):
     with pytest.raises(thumb.ThumbGenerationError):
         thumb.generate(pipeline_id=61, video_path=str(video_path),
                         track_title="X", overlay_text=False)
+
+
+# ===== Video tests (replacing the FFmpeg-based tests) =====
+
+@pytest.fixture
+def encoder_env(monkeypatch):
+    monkeypatch.setattr(video, "ENCODER_URL", "http://192.168.45.59:8765")
+    monkeypatch.setattr(video, "NAS_VIDEOS_ROOT", "/volume1/docker/webpage/data/videos")
+    monkeypatch.setattr(video, "NAS_MUSIC_ROOT", "/volume1/docker/webpage/data/music")
+
+
+@respx.mock
+def test_generate_video_calls_remote_encoder(encoder_env, tmp_path, monkeypatch):
+    monkeypatch.setattr(storage, "VIDEO_DATA_DIR", str(tmp_path))
+    respx.post("http://192.168.45.59:8765/encode_video").mock(
+        return_value=Response(200, json={
+            "ok": True, "duration_ms": 12000,
+            "output_path_nas": "/volume1/docker/webpage/data/videos/3/video.mp4",
+            "output_bytes": 28000000,
+            "encoder": "h264_nvenc", "preset": "p4",
+        })
+    )
+    out = video.generate(
+        pipeline_id=3,
+        audio_path="/app/data/1c695df3.mp3",
+        cover_path="/app/data/videos/3/cover.jpg",
+        genre="lo-fi", duration_sec=120, resolution="1920x1080",
+        style="visualizer",
+    )
+    assert out["url"].endswith("/3/video.mp4")
+    assert out["used_fallback"] is False
+    assert out["encode_duration_ms"] == 12000
+
+
+@respx.mock
+def test_generate_video_raises_on_connection_error(encoder_env, monkeypatch, tmp_path):
+    monkeypatch.setattr(storage, "VIDEO_DATA_DIR", str(tmp_path))
+    respx.post("http://192.168.45.59:8765/encode_video").mock(
+        side_effect=httpx.ConnectError("Connection refused")
+    )
+    with pytest.raises(video.VideoGenerationError) as exc:
+        video.generate(
+            pipeline_id=4,
+            audio_path="/app/data/x.mp3", cover_path="/app/data/videos/4/cover.jpg",
+            genre="lo-fi", duration_sec=120, resolution="1920x1080",
+        )
+    assert "연결 실패" in str(exc.value) or "Connection" in str(exc.value)
+
+
+@respx.mock
+def test_generate_video_raises_on_500(encoder_env, monkeypatch, tmp_path):
+    monkeypatch.setattr(storage, "VIDEO_DATA_DIR", str(tmp_path))
+    respx.post("http://192.168.45.59:8765/encode_video").mock(
+        return_value=Response(500, json={"detail": {"ok": False, "stage": "ffmpeg", "error": "bad codec"}})
+    )
+    with pytest.raises(video.VideoGenerationError) as exc:
+        video.generate(
+            pipeline_id=5,
+            audio_path="/app/data/x.mp3", cover_path="/app/data/videos/5/cover.jpg",
+            genre="lo-fi", duration_sec=120, resolution="1920x1080",
+        )
+    assert "Windows 인코더 오류" in str(exc.value)
+    assert "ffmpeg" in str(exc.value)
+
+
+def test_generate_video_no_url_configured(monkeypatch, tmp_path):
+    monkeypatch.setattr(storage, "VIDEO_DATA_DIR", str(tmp_path))
+    monkeypatch.setattr(video, "ENCODER_URL", "")
+    with pytest.raises(video.VideoGenerationError) as exc:
+        video.generate(
+            pipeline_id=6,
+            audio_path="/app/data/x.mp3", cover_path="/app/data/videos/6/cover.jpg",
+            genre="lo-fi", duration_sec=120, resolution="1920x1080",
+        )
+    assert "WINDOWS_VIDEO_ENCODER_URL" in str(exc.value)
+
+
+def test_container_to_nas_videos_path(monkeypatch):
+    monkeypatch.setattr(video, "NAS_VIDEOS_ROOT", "/volume1/docker/webpage/data/videos")
+    monkeypatch.setattr(video, "NAS_MUSIC_ROOT", "/volume1/docker/webpage/data/music")
+    assert video._container_to_nas("/app/data/videos/3/cover.jpg") == "/volume1/docker/webpage/data/videos/3/cover.jpg"
+
+
+def test_container_to_nas_music_path(monkeypatch):
+    monkeypatch.setattr(video, "NAS_VIDEOS_ROOT", "/volume1/docker/webpage/data/videos")
+    monkeypatch.setattr(video, "NAS_MUSIC_ROOT", "/volume1/docker/webpage/data/music")
+    assert video._container_to_nas("/app/data/abc.mp3") == "/volume1/docker/webpage/data/music/abc.mp3"