1227e8b345
RTP timestams helper functions moved from rtp_utility added functions to deal with CompactNtp timestamps R=åsapersson BUG=webrtc:5260 Review URL: https://codereview.webrtc.org/1535113002 Cr-Commit-Position: refs/heads/master@{#11106}
49 lines
1.8 KiB
C++
49 lines
1.8 KiB
C++
/*
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* Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef WEBRTC_MODULES_RTP_RTCP_SOURCE_TIME_UTIL_H_
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#define WEBRTC_MODULES_RTP_RTCP_SOURCE_TIME_UTIL_H_
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#include "webrtc/base/basictypes.h"
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#include "webrtc/system_wrappers/include/ntp_time.h"
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namespace webrtc {
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// Converts NTP timestamp to RTP timestamp.
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inline uint32_t NtpToRtp(NtpTime ntp, uint32_t freq) {
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uint32_t tmp = (static_cast<uint64_t>(ntp.fractions()) * freq) >> 32;
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return ntp.seconds() * freq + tmp;
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}
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// Return the current RTP timestamp from the NTP timestamp
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// returned by the specified clock.
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inline uint32_t CurrentRtp(const Clock& clock, uint32_t freq) {
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return NtpToRtp(NtpTime(clock), freq);
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}
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// Helper function for compact ntp representation:
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// RFC 3550, Section 4. Time Format.
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// Wallclock time is represented using the timestamp format of
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// the Network Time Protocol (NTP).
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// ...
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// In some fields where a more compact representation is
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// appropriate, only the middle 32 bits are used; that is, the low 16
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// bits of the integer part and the high 16 bits of the fractional part.
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inline uint32_t CompactNtp(NtpTime ntp) {
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return (ntp.seconds() << 16) | (ntp.fractions() >> 16);
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}
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// Converts interval between compact ntp timestamps to milliseconds.
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// This interval can be upto ~18.2 hours (2^16 seconds).
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inline uint32_t CompactNtpIntervalToMs(uint32_t compact_ntp_interval) {
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return static_cast<uint64_t>(compact_ntp_interval) * 1000 / (1 << 16);
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}
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} // namespace webrtc
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#endif // WEBRTC_MODULES_RTP_RTCP_SOURCE_TIME_UTIL_H_
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