media/cast/rtp_timestamp_helper.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "media/cast/rtp_timestamp_helper.h"
   6
   7 namespace media {
   8 namespace cast {
   9
  10 RtpTimestampHelper::RtpTimestampHelper(int frequency)
  11     : frequency_(frequency),
  12       last_rtp_timestamp_(0) {
  13 }
  14
  15 RtpTimestampHelper::~RtpTimestampHelper() {
  16 }
  17
  18 bool RtpTimestampHelper::GetCurrentTimeAsRtpTimestamp(
  19     const base::TimeTicks& now, uint32* rtp_timestamp) const {
  20   if (last_capture_time_.is_null())
  21     return false;
  22   const base::TimeDelta elapsed_time = now - last_capture_time_;
  23   const int64 rtp_delta =
  24       elapsed_time * frequency_ / base::TimeDelta::FromSeconds(1);
  25   *rtp_timestamp = last_rtp_timestamp_ + static_cast<uint32>(rtp_delta);
  26   return true;
  27 }
  28
  29 void RtpTimestampHelper::StoreLatestTime(
  30     base::TimeTicks capture_time, uint32 rtp_timestamp) {
  31   last_capture_time_ = capture_time;
  32   last_rtp_timestamp_ = rtp_timestamp;
  33 }
  34
  35 }  // namespace cast
  36 }  // namespace media