Add support for Biocam brw v4.x files

src/probeinterface/io.py

@@ -554,17 +554,38 @@ def read_3brain(file: Union[str, Path], mea_pitch: float = 42, electrode_width:
     --------
     probe : Probe object
 
+    Notes
+    -----
+    In case of multiple wells, the function will return the probe of the first plate.
+
     """
     file = Path(file).absolute()
     assert file.is_file()
 
     h5py = import_safely("h5py")
     rf = h5py.File(file, "r")
+    if "3BRecInfo" in rf.keys():  # brw v3.x
+        # get channel positions
+        channels = rf["3BRecInfo/3BMeaStreams/Raw/Chs"][:]
+        rows = channels["Row"] - 1
+        cols = channels["Col"] - 1
+    else:  # brw v4.x
+        num_channels = None
+        for key in rf:
+            if key.startswith("Well_"):
+                num_channels = len(rf[key]["StoredChIdxs"])
+                break
+        assert num_channels is not None, "No Well found in the file"
+
+        num_channels_x = num_channels_y = int(np.sqrt(num_channels))
+        if num_channels_x * num_channels_y != num_channels:
+            raise RuntimeError(
+                f"Electrode configuration is not a square. Cannot determine configuration of the MEA "
+                f"plate with {num_channels} channels"
+            )
+        rows = np.repeat(range(num_channels_x), num_channels_y)
+        cols = np.tile(range(num_channels_y), num_channels_x)
 
-    # get channel positions
-    channels = rf["3BRecInfo/3BMeaStreams/Raw/Chs"][:]
-    rows = channels["Row"] - 1
-    cols = channels["Col"] - 1
     positions = np.vstack((rows, cols)).T * mea_pitch
 
     probe = Probe(ndim=2, si_units="um")