phase 1

detect/checkpoint/frames.py

@@ -78,3 +78,34 @@ def load_frames(manifest: dict[int, str], frame_metadata: list[dict]) -> list[Fr
 
     frames.sort(key=lambda f: f.sequence)
     return frames
+
+
+def load_frames_b64(manifest: dict[int, str], frame_metadata: list[dict]) -> list[dict]:
+    """
+    Load frame images from S3 as base64 JPEG — lightweight, no numpy.
+
+    Returns list of dicts: {seq, timestamp, jpeg_b64}
+    """
+    import base64
+    from core.storage.s3 import download_to_temp
+
+    meta_map = {m["sequence"]: m for m in frame_metadata}
+    frames = []
+
+    for seq, key in manifest.items():
+        tmp_path = download_to_temp(BUCKET, key)
+        try:
+            with open(tmp_path, "rb") as f:
+                jpeg_bytes = f.read()
+        finally:
+            os.unlink(tmp_path)
+
+        meta = meta_map.get(seq, {})
+        frames.append({
+            "seq": seq,
+            "timestamp": meta.get("timestamp", 0.0),
+            "jpeg_b64": base64.b64encode(jpeg_bytes).decode(),
+        })
+
+    frames.sort(key=lambda f: f["seq"])
+    return frames