GoPro gyro extraction implemented

Author: ElvinC

GPMF_gyro.py

@@ -4,29 +4,39 @@
 import gpmf.parse as gpmf_parse
 from gpmf.extract import get_gpmf_payloads_from_file
 import sys
-    
+import numpy as np
+from matplotlib import pyplot as plt
 
 class Extractor:
     def __init__(self, videopath = "hero5.mp4"):
         self.videopath = videopath
 
         payloads, parser = get_gpmf_payloads_from_file(videopath)
 
+        self.parsed = []
+
         for gpmf_data, timestamps in payloads:
-            for element, parents in gpmf_parse.recursive(gpmf_data):
-                try:
-                    value = gpmf_parse.parse_value(element)
-                except ValueError:
-                    value = element.data
-                print("{} {} > {}: {}".format(
-                    timestamps,
-                    ' > '.join([x.decode('ascii') for x in parents]),
-                    element.key.decode('ascii'),
-                    value
-                ))
+            self.parsed.append(gpmf_parse.parse_dict(gpmf_data))
+
+            
+
+                
 
     def get_gyro(self):
-        return 1
+        self.gyro = []
+        self.scal = 0
+        for frame in self.parsed:
+            for stream in frame["DEVC"]["STRM"]:
+                if "GYRO" in stream:
+                    self.gyro += stream["GYRO"]
+                    self.scal = stream["SCAL"]
+        
+        
+        
+        omega = np.array(self.gyro) / self.scal
+
+        plt.plot(omega[:,0])
+        plt.show()
 
     def get_accl(self):
         return 1
@@ -36,4 +46,5 @@ def get_video_length(self):
 
 
 if __name__ == "__main__":
-    testing = Extractor()
+    testing = Extractor()
+    testing.get_gyro()

gpmf/parse.py

@@ -1,6 +1,7 @@
+# Derived from:
+# https://github.com/rambo/python-gpmf
 # The MIT License (MIT)
 # Copyright (c) 2014 Eero af Heurlin
-# https://github.com/rambo/python-gpmf
 
 #!/usr/bin/env python3
 """Parses the FOURCC data in GPMF stream into fields"""
@@ -42,6 +43,9 @@
 
 def parse_value(element):
     """Parses element value"""
+    if not element:
+        return "HELLOWTHERE"
+
     type_parsed = TYPES.parse(bytes([element.type]))
     #print("DEBUG: type_parsed={}, element.repeat={}, element.size={}, len(element.data): {}".format(type_parsed, element.repeat, element.size, len(element.data)))
 
@@ -123,7 +127,49 @@ def recursive(data, parents=tuple()):
                 yield subyield
         else:
             yield (element, parents)
+    
+def parse_list(data, parent = []):
+    elements = construct.GreedyRange(FOURCC).parse(data)
+    
+    out_list = []
+    for element in elements:
+        if element.type == 0:
+            
+            out_list.append(parse_list(element.data, out_list))
+        else: 
+            try: 
+                value = parse_value(element)
+            except ValueError:
+                value = element.data
+
+            out_list.append(value)
+            print(element.key)
+
+    return out_list
+
+def parse_dict(data):
+    """Parse data into a dict recursively
+    """
+
+    elements = construct.GreedyRange(FOURCC).parse(data)
+    new_dict = dict()
+
+    for element in elements:
+        if element.type == 0:
+
+            if (element.key.decode('ascii') == "STRM"):
+                new_dict.setdefault("STRM", []).append(parse_dict(element.data))
+            else:
+                new_dict[element.key.decode('ascii')] = parse_dict(element.data)
+            
+        else: 
+            try: 
+                value = parse_value(element)
+            except ValueError:
+                value = element.data
+            new_dict[element.key.decode('ascii')] = value
 
+    return new_dict
 
 if __name__ == '__main__':
     import sys