New rtc dump analyzing tool in Python

tools/py_event_log_analyzer/pb_parse.py

+#  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+#
+#  Use of this source code is governed by a BSD-style license
+#  that can be found in the LICENSE file in the root of the source
+#  tree. An additional intellectual property rights grant can be found
+#  in the file PATENTS.  All contributing project authors may
+#  be found in the AUTHORS file in the root of the source tree.
+
+"""Parses protobuf RTC dumps.
+"""
+
+from __future__ import division
+
+import os
+import struct
+import sys
+
+
+# makes sure to import correct protobuf
+sys.path += [os.path.join("../../", path) for path in
+             ["out/Debug/pyproto/webrtc/call/",
+              "out/Release/pyproto/webrtc/call/",
+              "third_party/protobuf/python/"]]
+import rtc_event_log_pb2 as rtc_pb
+
+
+class DataPoint(object):
+  """Simple container class for RTP events.
+  """
+
+  def __init__(self, rtp_header_str, packet_size,
+               arrival_timestamp_us):
+    """Builds a data point by parsing an RTP header, and extra information
+    about packet size and arrival time.
+
+    RTP header structure is defined in RFC 3550 section 5.1.
+
+    """
+    self.size = packet_size
+    self.arrival_timestamp_ms = arrival_timestamp_us / 1000
+    (first2header_bytes, self.sequence_number,
+     self.timestamp, self.ssrc
+    ) = struct.unpack_from("!HHII", rtp_header_str, 0)
+    self.payload_type = first2header_bytes & 0b01111111
+
+
+def parse_protobuf(file_path):
+  """Parses RTC event log from protobuf file.
+
+  Args:
+       file_path: path to protobuf file of RTC event stream
+
+  Returns:
+    all RTP packet events from the event stream as a list of DataPoints
+  """
+  event_stream = rtc_pb.EventStream()
+  with open(file_path, "rb") as f:
+    event_stream.ParseFromString(f.read())
+
+  return [DataPoint(event.rtp_packet.header,
+                    event.rtp_packet.packet_length,
+                    event.timestamp_us)
+          for event in event_stream.stream
+          if event.HasField("rtp_packet")]