feat(music-lab): pipeline 영상·썸네일 생성

music-lab/app/pipeline/thumb.py

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+"""썸네일 생성 — 영상 5초 프레임 추출 + 텍스트 오버레이."""
+import os
+import subprocess
+import logging
+from PIL import Image, ImageDraw, ImageFont
+
+from . import storage
+
+logger = logging.getLogger("music-lab.thumb")
+THUMB_TIMEOUT_S = 60
+
+
+class ThumbGenerationError(Exception):
+    pass
+
+
+def generate(*, pipeline_id: int, video_path: str,
+             track_title: str = "", overlay_text: bool = True) -> dict:
+    out_path = os.path.join(storage.pipeline_dir(pipeline_id), "thumbnail.jpg")
+    cmd = ["ffmpeg", "-y", "-i", video_path,
+           "-ss", "00:00:05", "-vframes", "1", "-q:v", "2", out_path]
+    result = subprocess.run(cmd, capture_output=True, text=True, timeout=THUMB_TIMEOUT_S)
+    if result.returncode != 0:
+        raise ThumbGenerationError(f"ffmpeg 썸네일 실패: {result.stderr[:300]}")
+
+    if overlay_text and track_title:
+        _overlay_title(out_path, track_title)
+
+    return {"url": storage.media_url(pipeline_id, "thumbnail.jpg"), "used_fallback": False}
+
+
+def _overlay_title(path: str, title: str) -> None:
+    try:
+        with Image.open(path) as src:
+            img = src.convert("RGB")
+        try:
+            font = ImageFont.truetype("/usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf", 80)
+        except OSError:
+            font = ImageFont.load_default()
+        draw = ImageDraw.Draw(img)
+        # 하단 30% 영역에 검정 반투명 박스 + 흰 글씨
+        w, h = img.size
+        box_h = int(h * 0.3)
+        with Image.new("RGBA", (w, box_h), (0, 0, 0, 160)) as overlay:
+            img.paste(overlay, (0, h - box_h), overlay)
+        bbox = draw.textbbox((0, 0), title, font=font)
+        tw = bbox[2] - bbox[0]
+        draw.text(((w - tw) // 2, h - box_h + 30), title, fill=(255, 255, 255), font=font)
+        img.save(path, "JPEG", quality=92)
+    except Exception as e:
+        logger.warning("썸네일 오버레이 실패: %s", e)

music-lab/app/pipeline/video.py

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+"""영상 비주얼 생성 — visualizer/슬라이드쇼 스타일."""
+import os
+import subprocess
+import logging
+
+from . import storage
+
+logger = logging.getLogger("music-lab.video")
+
+VIDEO_TIMEOUT_S = 300  # 5분
+
+
+class VideoGenerationError(Exception):
+    pass
+
+
+def generate(*, pipeline_id: int, audio_path: str, cover_path: str,
+             genre: str, duration_sec: int, resolution: str = "1920x1080",
+             style: str = "visualizer") -> dict:
+    """영상 생성. 성공 시 mp4 저장 + URL 반환. 실패 시 예외."""
+    w, h = resolution.split("x")
+    out_path = os.path.join(storage.pipeline_dir(pipeline_id), "video.mp4")
+
+    if style == "visualizer":
+        cmd = _build_visualizer_cmd(audio_path, cover_path, out_path, w, h)
+    else:
+        # 차후: 슬라이드쇼 등 다른 스타일 — 현재는 visualizer 폴백
+        cmd = _build_visualizer_cmd(audio_path, cover_path, out_path, w, h)
+
+    logger.info("ffmpeg 실행: %s", " ".join(cmd))
+    result = subprocess.run(cmd, capture_output=True, text=True, timeout=VIDEO_TIMEOUT_S)
+    if result.returncode != 0:
+        raise VideoGenerationError(f"ffmpeg 실패: {result.stderr[:500]}")
+
+    return {
+        "url": storage.media_url(pipeline_id, "video.mp4"),
+        "used_fallback": False,
+        "duration_sec": duration_sec,
+    }
+
+
+def _build_visualizer_cmd(audio: str, bg: str, out: str, w: str, h: str) -> list:
+    return [
+        "ffmpeg", "-y",
+        "-loop", "1", "-i", bg,
+        "-i", audio,
+        "-filter_complex",
+        f"[0:v]scale={w}:{h}[bg];"
+        f"[1:a]showwaves=s={w}x200:mode=cline:colors=0xFF4444@0.8[wave];"
+        f"[bg][wave]overlay=0:({h}-200)[out]",
+        "-map", "[out]", "-map", "1:a",
+        "-c:v", "libx264", "-preset", "fast", "-crf", "23",
+        "-c:a", "aac", "-b:a", "192k",
+        "-shortest", out,
+    ]