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1#  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
2#
3#  Use of this source code is governed by a BSD-style license
4#  that can be found in the LICENSE file in the root of the source
5#  tree. An additional intellectual property rights grant can be found
6#  in the file PATENTS.  All contributing project authors may
7#  be found in the AUTHORS file in the root of the source tree.
8
9"""Parses protobuf RTC dumps."""
10
11from __future__ import division
12import struct
13import pyproto.logging.rtc_event_log.rtc_event_log_pb2 as rtc_pb
14
15
16class DataPoint(object):
17  """Simple container class for RTP events."""
18
19  def __init__(self, rtp_header_str, packet_size,
20               arrival_timestamp_us, incoming):
21    """Builds a data point by parsing an RTP header, size and arrival time.
22
23    RTP header structure is defined in RFC 3550 section 5.1.
24    """
25    self.size = packet_size
26    self.arrival_timestamp_ms = arrival_timestamp_us / 1000
27    self.incoming = incoming
28    header = struct.unpack_from("!HHII", rtp_header_str, 0)
29    (first2header_bytes, self.sequence_number, self.timestamp,
30     self.ssrc) = header
31    self.payload_type = first2header_bytes & 0b01111111
32    self.marker_bit = (first2header_bytes & 0b10000000) >> 7
33
34
35def ParseProtobuf(file_path):
36  """Parses RTC event log from protobuf file.
37
38  Args:
39       file_path: path to protobuf file of RTC event stream
40
41  Returns:
42    all RTP packet events from the event stream as a list of DataPoints
43  """
44  event_stream = rtc_pb.EventStream()
45  with open(file_path, "rb") as f:
46    event_stream.ParseFromString(f.read())
47
48  return [DataPoint(event.rtp_packet.header,
49                    event.rtp_packet.packet_length,
50                    event.timestamp_us, event.rtp_packet.incoming)
51          for event in event_stream.stream
52          if event.HasField("rtp_packet")]
53