feat(video_analysis): ocr_frames.py with TDD (4 tests, winsdk + tesseract backends)

scripts/video_analysis/ocr_frames.py

@@ -0,0 +1,110 @@
+from __future__ import annotations
+
+import asyncio
+from dataclasses import dataclass
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Any
+
+from scripts.video_analysis.error_types import ErrorInfo, make_error
+
+
+@dataclass
+class _Ok:
+ value: Any
+
+ def is_ok(self) -> bool:
+  return True
+
+ def is_err(self) -> bool:
+  return False
+
+
+@dataclass
+class _Err:
+ err: ErrorInfo
+
+ def is_ok(self) -> bool:
+  return False
+
+ def is_err(self) -> bool:
+  return True
+
+
+def ok(value: Any) -> _Ok:
+ return _Ok(value)
+
+
+def err(error: ErrorInfo) -> _Err:
+ return _Err(error)
+
+
+def list_frame_files(frames_dir: Path) -> list[Path]:
+ return sorted(p for p in frames_dir.glob("frame_*.jpg"))
+
+
+def _ocr_single_image(image_path: Path, backend: str) -> tuple[str, float]:
+ if backend == "winsdk":
+  return _ocr_winsdk(image_path)
+ if backend == "tesseract":
+  return _ocr_tesseract(image_path)
+ raise ValueError(f"Unknown OCR backend: {backend}")
+
+
+def _ocr_winsdk(image_path: Path) -> tuple[str, float]:
+ from winsdk.windows.storage import StorageFile
+ from winsdk.windows.graphics.imaging import BitmapDecoder
+ from winsdk.windows.media.ocr import OcrEngine
+ from winsdk.windows.globalization import Language
+
+ async def _run() -> str:
+  file = await StorageFile.get_file_from_path_async(str(image_path.resolve()))
+  stream = await file.open_read_async()
+  decoder = await BitmapDecoder.create_async(stream)
+  bitmap = await decoder.get_software_bitmap_async()
+  engine = OcrEngine.try_create_from_language(Language("en-US"))
+  if not engine:
+   return ""
+  result = await engine.recognize_async(bitmap)
+  return "\n".join(line.text for line in result.lines)
+
+ text = asyncio.run(_run())
+ return text, 0.9 if text else 0.0
+
+
+def _ocr_tesseract(image_path: Path) -> tuple[str, float]:
+ import pytesseract
+ from PIL import Image
+ img = Image.open(image_path)
+ text = pytesseract.image_to_string(img)
+ return text, 0.85 if text.strip() else 0.0
+
+
+def format_ocr_markdown(frames: list[tuple[str, str, str]]) -> str:
+ lines = ["# OCR Results", ""]
+ for filename, text, _timestamp in frames:
+  lines.append(f"## {filename}")
+  lines.append("")
+  lines.append("```")
+  lines.append(text or "(no text extracted)")
+  lines.append("```")
+  lines.append("")
+ return "\n".join(lines)
+
+
+def ocr_frames(frames_dir: Path, output: Path, backend: str = "winsdk") -> _Ok | _Err:
+ if not frames_dir.exists():
+  return err(make_error("FramesDirNotFound", "ocr_frames", str(frames_dir)))
+ frames = list_frame_files(frames_dir)
+ if not frames:
+  return err(make_error("NoFramesFound", "ocr_frames", str(frames_dir)))
+ now = datetime.now(timezone.utc).isoformat()
+ results: list[tuple[str, str, str]] = []
+ for frame_path in frames:
+  try:
+   text, confidence = _ocr_single_image(frame_path, backend)
+  except Exception as e:
+   return err(make_error("OcrError", "ocr_frames", f"{frame_path}: {e}"))
+  results.append((frame_path.name, text, now))
+ output.write_text(format_ocr_markdown(results), encoding="utf-8")
+ return ok({"frames_ocrd": len(results), "output": str(output), "backend": backend})