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 <stdint.h>
   9
  10 #include <map>
  11 #include <set>
  12
  13 #include "base/basictypes.h"
  14 #include "base/compiler_specific.h"
  15 #include "base/logging.h"
  16 #include "base/time/time.h"
  17 #include "media/cast/net/cast_transport_config.h"
  18
  19 namespace media {
  20 namespace cast {
  21
  22 const int64 kDontShowTimeoutMs = 33;
  23 const float kDefaultCongestionControlBackOff = 0.875f;
  24 const uint32 kVideoFrequency = 90000;
  25 const uint32 kStartFrameId = UINT32_C(0xffffffff);
  26
  27 // This is an important system-wide constant.  This limits how much history the
  28 // implementation must retain in order to process the acknowledgements of past
  29 // frames.
  30 const int kMaxUnackedFrames = 255;
  31
  32 const int kStartRttMs = 20;
  33 const int64 kCastMessageUpdateIntervalMs = 33;
  34 const int64 kNackRepeatIntervalMs = 30;
  35
  36 enum CastInitializationStatus {
  37   STATUS_AUDIO_UNINITIALIZED,
  38   STATUS_VIDEO_UNINITIALIZED,
  39   STATUS_AUDIO_INITIALIZED,
  40   STATUS_VIDEO_INITIALIZED,
  41   STATUS_INVALID_CAST_ENVIRONMENT,
  42   STATUS_INVALID_CRYPTO_CONFIGURATION,
  43   STATUS_UNSUPPORTED_AUDIO_CODEC,
  44   STATUS_UNSUPPORTED_VIDEO_CODEC,
  45   STATUS_INVALID_AUDIO_CONFIGURATION,
  46   STATUS_INVALID_VIDEO_CONFIGURATION,
  47   STATUS_GPU_ACCELERATION_NOT_SUPPORTED,
  48   STATUS_GPU_ACCELERATION_ERROR,
  49 };
  50
  51 enum DefaultSettings {
  52   kDefaultAudioEncoderBitrate = 0,  // This means "auto," and may mean VBR.
  53   kDefaultAudioSamplingRate = 48000,
  54   kDefaultMaxQp = 56,
  55   kDefaultMinQp = 4,
  56   kDefaultMaxFrameRate = 30,
  57   kDefaultNumberOfVideoBuffers = 1,
  58   kDefaultRtcpIntervalMs = 500,
  59   kDefaultRtpHistoryMs = 1000,
  60   kDefaultRtpMaxDelayMs = 100,
  61 };
  62
  63 enum PacketType {
  64   kNewPacket,
  65   kNewPacketCompletingFrame,
  66   kDuplicatePacket,
  67   kTooOldPacket,
  68 };
  69
  70 // kRtcpCastAllPacketsLost is used in PacketIDSet and
  71 // on the wire to mean that ALL packets for a particular
  72 // frame are lost.
  73 const uint16 kRtcpCastAllPacketsLost = 0xffff;
  74
  75 // kRtcpCastLastPacket is used in PacketIDSet to ask for
  76 // the last packet of a frame to be retransmitted.
  77 const uint16 kRtcpCastLastPacket = 0xfffe;
  78
  79 const size_t kMinLengthOfRtcp = 8;
  80
  81 // Basic RTP header + cast header.
  82 const size_t kMinLengthOfRtp = 12 + 6;
  83
  84 // Each uint16 represents one packet id within a cast frame.
  85 // Can also contain kRtcpCastAllPacketsLost and kRtcpCastLastPacket.
  86 typedef std::set<uint16> PacketIdSet;
  87 // Each uint8 represents one cast frame.
  88 typedef std::map<uint8, PacketIdSet> MissingFramesAndPacketsMap;
  89
  90 // TODO(pwestin): Re-factor the functions bellow into a class with static
  91 // methods.
  92
  93 // January 1970, in NTP seconds.
  94 // Network Time Protocol (NTP), which is in seconds relative to 0h UTC on
  95 // 1 January 1900.
  96 static const int64 kUnixEpochInNtpSeconds = INT64_C(2208988800);
  97
  98 // Magic fractional unit. Used to convert time (in microseconds) to/from
  99 // fractional NTP seconds.
 100 static const double kMagicFractionalUnit = 4.294967296E3;
 101
 102 // The maximum number of Cast receiver events to keep in history for the
 103 // purpose of sending the events through RTCP.
 104 // The number chosen should be more than the number of events that can be
 105 // stored in a RTCP packet.
 106 static const size_t kReceiverRtcpEventHistorySize = 512;
 107
 108 inline bool IsNewerFrameId(uint32 frame_id, uint32 prev_frame_id) {
 109   return (frame_id != prev_frame_id) &&
 110          static_cast<uint32>(frame_id - prev_frame_id) < 0x80000000;
 111 }
 112
 113 inline bool IsNewerRtpTimestamp(uint32 timestamp, uint32 prev_timestamp) {
 114   return (timestamp != prev_timestamp) &&
 115          static_cast<uint32>(timestamp - prev_timestamp) < 0x80000000;
 116 }
 117
 118 inline bool IsOlderFrameId(uint32 frame_id, uint32 prev_frame_id) {
 119   return (frame_id == prev_frame_id) || IsNewerFrameId(prev_frame_id, frame_id);
 120 }
 121
 122 inline bool IsNewerPacketId(uint16 packet_id, uint16 prev_packet_id) {
 123   return (packet_id != prev_packet_id) &&
 124          static_cast<uint16>(packet_id - prev_packet_id) < 0x8000;
 125 }
 126
 127 inline bool IsNewerSequenceNumber(uint16 sequence_number,
 128                                   uint16 prev_sequence_number) {
 129   // Same function as IsNewerPacketId just different data and name.
 130   return IsNewerPacketId(sequence_number, prev_sequence_number);
 131 }
 132
 133 // Create a NTP diff from seconds and fractions of seconds; delay_fraction is
 134 // fractions of a second where 0x80000000 is half a second.
 135 inline uint32 ConvertToNtpDiff(uint32 delay_seconds, uint32 delay_fraction) {
 136   return ((delay_seconds & 0x0000FFFF) << 16) +
 137          ((delay_fraction & 0xFFFF0000) >> 16);
 138 }
 139
 140 inline base::TimeDelta ConvertFromNtpDiff(uint32 ntp_delay) {
 141   uint32 delay_ms = (ntp_delay & 0x0000ffff) * 1000;
 142   delay_ms >>= 16;
 143   delay_ms += ((ntp_delay & 0xffff0000) >> 16) * 1000;
 144   return base::TimeDelta::FromMilliseconds(delay_ms);
 145 }
 146
 147 inline void ConvertTimeToFractions(int64 ntp_time_us,
 148                                    uint32* seconds,
 149                                    uint32* fractions) {
 150   DCHECK_GE(ntp_time_us, 0) << "Time must NOT be negative";
 151   const int64 seconds_component =
 152       ntp_time_us / base::Time::kMicrosecondsPerSecond;
 153   // NTP time will overflow in the year 2036.  Also, make sure unit tests don't
 154   // regress and use an origin past the year 2036.  If this overflows here, the
 155   // inverse calculation fails to compute the correct TimeTicks value, throwing
 156   // off the entire system.
 157   DCHECK_LT(seconds_component, INT64_C(4263431296))
 158       << "One year left to fix the NTP year 2036 wrap-around issue!";
 159   *seconds = static_cast<uint32>(seconds_component);
 160   *fractions = static_cast<uint32>(
 161       (ntp_time_us % base::Time::kMicrosecondsPerSecond) *
 162           kMagicFractionalUnit);
 163 }
 164
 165 inline void ConvertTimeTicksToNtp(const base::TimeTicks& time,
 166                                   uint32* ntp_seconds,
 167                                   uint32* ntp_fractions) {
 168   base::TimeDelta elapsed_since_unix_epoch =
 169       time - base::TimeTicks::UnixEpoch();
 170
 171   int64 ntp_time_us =
 172       elapsed_since_unix_epoch.InMicroseconds() +
 173       (kUnixEpochInNtpSeconds * base::Time::kMicrosecondsPerSecond);
 174
 175   ConvertTimeToFractions(ntp_time_us, ntp_seconds, ntp_fractions);
 176 }
 177
 178 inline base::TimeTicks ConvertNtpToTimeTicks(uint32 ntp_seconds,
 179                                              uint32 ntp_fractions) {
 180   int64 ntp_time_us =
 181       static_cast<int64>(ntp_seconds) * base::Time::kMicrosecondsPerSecond +
 182       static_cast<int64>(ntp_fractions) / kMagicFractionalUnit;
 183
 184   base::TimeDelta elapsed_since_unix_epoch = base::TimeDelta::FromMicroseconds(
 185       ntp_time_us -
 186       (kUnixEpochInNtpSeconds * base::Time::kMicrosecondsPerSecond));
 187   return base::TimeTicks::UnixEpoch() + elapsed_since_unix_epoch;
 188 }
 189
 190 inline base::TimeDelta RtpDeltaToTimeDelta(int64 rtp_delta, int rtp_timebase) {
 191   DCHECK_GT(rtp_timebase, 0);
 192   return rtp_delta * base::TimeDelta::FromSeconds(1) / rtp_timebase;
 193 }
 194
 195 }  // namespace cast
 196 }  // namespace media
 197
 198 #endif  // MEDIA_CAST_CAST_DEFINES_H_