diff --git a/src/gateware/cxp_frame_pipeline.py b/src/gateware/cxp_frame_pipeline.py
index 0c52ef5..33bc038 100644
--- a/src/gateware/cxp_frame_pipeline.py
+++ b/src/gateware/cxp_frame_pipeline.py
@@ -159,7 +159,7 @@ class CXPCRC32_Checker(Module):
     
         
 class Stream_Broadcaster(Module):
-    def __init__(self, n_buffer, default_id=0):
+    def __init__(self, n_buffer=1, default_id=0):
         assert n_buffer > 0
 
         self.routing_ids = [Signal(char_width) for _ in range(1, n_buffer)]
@@ -539,9 +539,12 @@ class Pixel_Gearbox(Module):
             ),
         ]
 
-class Pixel_Parser(Module):
-    """Parses the 4x pixels and track pixel coordinates."""
+class Pixel_Coordinate_Tracker(Module):
+    """track pixel coordinates."""
     def __init__(self, res_width):
+    # largest x/y pixel size supported by frame header are 24 bits
+        assert res_width == 3*char_width
+
         self.y_size = Signal(3*char_width)
         self.sink = stream.Endpoint(pixel4x_layout)
 
@@ -687,7 +690,7 @@ class ROI(Module):
 
         
 
-class Frame_Deserializer(Module):
+class Pixel_Parser(Module):
     def __init__(self, res_width):
         # TODO: use new_frame or remove it
         self.new_frame = Signal()
@@ -719,9 +722,9 @@ class Frame_Deserializer(Module):
             "mono16": 0x0105,
         }
 
-        self.submodules.parser = parser = Pixel_Parser(res_width)
-        self.sync += parser.y_size.eq(self.y_size)
-        self.pixel4x = parser.pixel4x
+        self.submodules.tracker = tracker = Pixel_Coordinate_Tracker(res_width)
+        self.sync += tracker.y_size.eq(self.y_size)
+        self.pixel4x = tracker.pixel4x
 
         mux_cases = {
             "default": [
@@ -732,7 +735,7 @@ class Frame_Deserializer(Module):
         for fmt in pix_fmt:
             mux_cases[pix_fmt[fmt]] = [
                 eol_inserter.source.connect(gearboxes[fmt].sink),
-                gearboxes[fmt].source.connect(parser.sink),
+                gearboxes[fmt].source.connect(tracker.sink),
             ]
 
         self.comb += Case(self.pixel_format, mux_cases)
@@ -740,7 +743,6 @@ class Frame_Deserializer(Module):
 
 
 class ROI_Pipeline(Module):
-    # largest x/y pixel size supported by frame header are 24 bits
     def __init__(self, res_width, count_width):
 
         # NOTE: csr need to stay outside since this module need to be cdr in the CXP_FRAME_Pipeline module
@@ -750,19 +752,19 @@ class ROI_Pipeline(Module):
         self.submodules.buffer = buffer = Buffer(word_layout_dchar) # to improve timing from broadcaster
         self.submodules.crc_checker = crc_checker = CXPCRC32_Checker()
         self.submodules.header_decoder = header_decoder = Frame_Header_Decoder()
-        self.submodules.deserializer = deserializer = Frame_Deserializer(res_width)
+        self.submodules.parser = parser = Pixel_Parser(res_width)
 
-        self.submodules.roi = ROI(deserializer.pixel4x, count_width)
+        self.submodules.roi = ROI(parser.pixel4x, count_width)
 
         self.comb += [
-            deserializer.new_frame.eq(header_decoder.new_frame),
-            deserializer.l_size.eq(header_decoder.metadata.l_size),
-            deserializer.x_size.eq(header_decoder.metadata.x_size),
-            deserializer.y_size.eq(header_decoder.metadata.y_size),
-            deserializer.pixel_format.eq(header_decoder.metadata.pixel_format),
+            parser.new_frame.eq(header_decoder.new_frame),
+            parser.l_size.eq(header_decoder.metadata.l_size),
+            parser.x_size.eq(header_decoder.metadata.x_size),
+            parser.y_size.eq(header_decoder.metadata.y_size),
+            parser.pixel_format.eq(header_decoder.metadata.pixel_format),
         ]
 
-        self.pipeline = [buffer, crc_checker, header_decoder, deserializer]
+        self.pipeline = [buffer, crc_checker, header_decoder, parser]
         for s, d in zip(self.pipeline, self.pipeline[1:]):
             self.comb += s.source.connect(d.sink)
         self.sink = self.pipeline[0].sink