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 struct
+import sys
+
+sys.path.append("../../third_party/protobuf/python/")
+
+import pyproto.webrtc.call.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, 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,

[phoglund, 2016/06/03 08:11:07]

Try this instead: 

header = struct.unpack_from("!HHII", rtp_header_str, 0)
first2header_bytes, self.sequence_number, self.timestamp, self.ssrc = header

[aleloi, 2016/06/09 12:00:44]

Here there are also divided views between different reviewers. I like the latest
suggestion more, because it is more readable, and because an extra local
variable is no big thing.

[kwiberg-webrtc, 2016/06/09 12:27:20]

Pro tip: If two reviewers give you conflicting advice, pick the option you like
best while the two of them are busy arguing.

I still like the current version best, but this function is small enough that
introducing an extra local variable doesn't hurt readability much.

[phoglund, 2016/06/09 12:47:08]

All right, I won't fight you on this.

+     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")]