added capture time for every sweep

python_app/storage/npz/serialize.py

@@ -22,7 +22,14 @@ def _write_interleaved_complex(buffer: bytearray, values: np.ndarray) -> None:
 
 
 def serialize_trace_collection(collection: SweepCollection, magic: int) -> bytes:
-    """Serialize one raw/preprocessed trace collection into ring-compatible binary format."""
+    """Serialize one raw/preprocessed trace collection into ring-compatible binary format.
+
+    The trailer is appended after the trace blocks so older readers, which stop at
+    the last block, still decode the traces: first the collection capture window,
+    then a per-trace window table (one ``(start_ns, end_ns)`` pair per trace, in
+    trace order). See :func:`python_app.orchestration.shm.decoder.decode_trace_collection`
+    and ``read_trace_collection`` in ``common_cpp/ipc/src/shared_types.cpp``.
+    """
     buffer = bytearray()
     buffer.extend(struct.pack("<IQQI", magic, collection.collection_id, collection.monotonic_ns, len(collection.traces)))
 
@@ -48,6 +55,11 @@ def serialize_trace_collection(collection: SweepCollection, magic: int) -> bytes
             int(collection.capture_end_ns),
         )
     )
+    buffer.extend(struct.pack("<I", len(collection.traces)))
+    for trace in collection.traces:
+        buffer.extend(
+            struct.pack("<QQ", int(trace.capture_start_ns), int(trace.capture_end_ns))
+        )
     return bytes(buffer)