media/cast/cast_defines.h

   1 // Copyright 2013 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 #ifndef MEDIA_CAST_CAST_DEFINES_H_
   6 #define MEDIA_CAST_CAST_DEFINES_H_
   7
   8 #include <map>
   9 #include <set>
  10
  11 #include "base/basictypes.h"
  12 #include "base/compiler_specific.h"
  13 #include "base/time/time.h"
  14
  15 namespace media {
  16 namespace cast {
  17
  18 const int64 kDontShowTimeoutMs = 33;
  19 const float kDefaultCongestionControlBackOff = 0.875f;
  20 const uint8 kStartFrameId = 255;
  21 const uint32 kVideoFrequency = 90000;
  22 const int64 kSkippedFramesCheckPeriodkMs = 10000;
  23
  24 // Number of skipped frames threshold in fps (as configured) per period above.
  25 const int kSkippedFramesThreshold = 3;
  26 const size_t kIpPacketSize = 1500;
  27 const int kStartRttMs = 20;
  28 const int64 kCastMessageUpdateIntervalMs = 33;
  29 const int64 kNackRepeatIntervalMs = 30;
  30
  31 enum DefaultSettings {
  32   kDefaultMaxQp = 56,
  33   kDefaultMinQp = 4,
  34   kDefaultMaxFrameRate = 30,
  35   kDefaultNumberOfVideoBuffers = 1,
  36   kDefaultRtcpIntervalMs = 500,
  37   kDefaultRtpHistoryMs = 1000,
  38   kDefaultRtpMaxDelayMs = 100,
  39 };
  40
  41 const uint16 kRtcpCastAllPacketsLost = 0xffff;
  42
  43 // Each uint16 represents one packet id within a cast frame.
  44 typedef std::set<uint16> PacketIdSet;
  45 // Each uint8 represents one cast frame.
  46 typedef std::map<uint8, PacketIdSet> MissingFramesAndPacketsMap;
  47
  48 // TODO(pwestin): Re-factor the functions bellow into a class with static
  49 // methods.
  50
  51 // Magic fractional unit. Used to convert time (in microseconds) to/from
  52 // fractional NTP seconds.
  53 static const double kMagicFractionalUnit = 4.294967296E3;
  54
  55 // Network Time Protocol (NTP), which is in seconds relative to 0h UTC on
  56 // 1 January 1900.
  57 static const int64 kNtpEpochDeltaSeconds = GG_INT64_C(9435484800);
  58 static const int64 kNtpEpochDeltaMicroseconds =
  59     kNtpEpochDeltaSeconds * base::Time::kMicrosecondsPerSecond;
  60
  61 inline bool IsNewerFrameId(uint8 frame_id, uint8 prev_frame_id) {
  62   return (frame_id != prev_frame_id) &&
  63       static_cast<uint8>(frame_id - prev_frame_id) < 0x80;
  64 }
  65
  66 inline bool IsOlderFrameId(uint8 frame_id, uint8 prev_frame_id) {
  67   return (frame_id == prev_frame_id) || IsNewerFrameId(prev_frame_id, frame_id);
  68 }
  69
  70 inline bool IsNewerPacketId(uint16 packet_id, uint16 prev_packet_id) {
  71   return (packet_id != prev_packet_id) &&
  72       static_cast<uint16>(packet_id - prev_packet_id) < 0x8000;
  73 }
  74
  75 inline bool IsNewerSequenceNumber(uint16 sequence_number,
  76                                   uint16 prev_sequence_number) {
  77   // Same function as IsNewerPacketId just different data and name.
  78   return IsNewerPacketId(sequence_number, prev_sequence_number);
  79 }
  80
  81 // Create a NTP diff from seconds and fractions of seconds; delay_fraction is
  82 // fractions of a second where 0x80000000 is half a second.
  83 inline uint32 ConvertToNtpDiff(uint32 delay_seconds, uint32 delay_fraction) {
  84   return ((delay_seconds & 0x0000FFFF) << 16) +
  85          ((delay_fraction & 0xFFFF0000) >> 16);
  86 }
  87
  88 inline base::TimeDelta ConvertFromNtpDiff(uint32 ntp_delay) {
  89   uint32 delay_ms = (ntp_delay & 0x0000ffff) * 1000;
  90   delay_ms >>= 16;
  91   delay_ms += ((ntp_delay & 0xffff0000) >> 16) * 1000;
  92   return base::TimeDelta::FromMilliseconds(delay_ms);
  93 }
  94
  95 inline void ConvertTimeToFractions(int64 time_us,
  96                                    uint32* seconds,
  97                                    uint32* fractions) {
  98   *seconds = static_cast<uint32>(time_us / base::Time::kMicrosecondsPerSecond);
  99   *fractions = static_cast<uint32>(
 100       (time_us % base::Time::kMicrosecondsPerSecond) * kMagicFractionalUnit);
 101 }
 102
 103 inline void ConvertTimeToNtp(const base::TimeTicks& time,
 104                              uint32* ntp_seconds,
 105                              uint32* ntp_fractions) {
 106   int64 time_us = time.ToInternalValue() - kNtpEpochDeltaMicroseconds;
 107   ConvertTimeToFractions(time_us, ntp_seconds, ntp_fractions);
 108 }
 109
 110 inline base::TimeTicks ConvertNtpToTime(uint32 ntp_seconds,
 111                                         uint32 ntp_fractions) {
 112   int64 ntp_time_us = static_cast<int64>(ntp_seconds) *
 113        base::Time::kMicrosecondsPerSecond;
 114   ntp_time_us += static_cast<int64>(ntp_fractions) / kMagicFractionalUnit;
 115   return base::TimeTicks::FromInternalValue(ntp_time_us +
 116       kNtpEpochDeltaMicroseconds);
 117 }
 118
 119 }  // namespace cast
 120 }  // namespace media
 121
 122 #endif  // MEDIA_CAST_CAST_DEFINES_H_