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/transport/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 size_t kMaxIpPacketSize = 1500;
  33 const int kStartRttMs = 20;
  34 const int64 kCastMessageUpdateIntervalMs = 33;
  35 const int64 kNackRepeatIntervalMs = 30;
  36
  37 enum CastInitializationStatus {
  38   STATUS_AUDIO_UNINITIALIZED,
  39   STATUS_VIDEO_UNINITIALIZED,
  40   STATUS_AUDIO_INITIALIZED,
  41   STATUS_VIDEO_INITIALIZED,
  42   STATUS_INVALID_CAST_ENVIRONMENT,
  43   STATUS_INVALID_CRYPTO_CONFIGURATION,
  44   STATUS_UNSUPPORTED_AUDIO_CODEC,
  45   STATUS_UNSUPPORTED_VIDEO_CODEC,
  46   STATUS_INVALID_AUDIO_CONFIGURATION,
  47   STATUS_INVALID_VIDEO_CONFIGURATION,
  48   STATUS_GPU_ACCELERATION_NOT_SUPPORTED,
  49   STATUS_GPU_ACCELERATION_ERROR,
  50 };
  51
  52 enum DefaultSettings {
  53   kDefaultAudioEncoderBitrate = 0,  // This means "auto," and may mean VBR.
  54   kDefaultAudioSamplingRate = 48000,
  55   kDefaultMaxQp = 56,
  56   kDefaultMinQp = 4,
  57   kDefaultMaxFrameRate = 30,
  58   kDefaultNumberOfVideoBuffers = 1,
  59   kDefaultRtcpIntervalMs = 500,
  60   kDefaultRtpHistoryMs = 1000,
  61   kDefaultRtpMaxDelayMs = 100,
  62 };
  63
  64 enum PacketType {
  65   kNewPacket,
  66   kNewPacketCompletingFrame,
  67   kDuplicatePacket,
  68   kTooOldPacket,
  69 };
  70
  71 // kRtcpCastAllPacketsLost is used in PacketIDSet and
  72 // on the wire to mean that ALL packets for a particular
  73 // frame are lost.
  74 const uint16 kRtcpCastAllPacketsLost = 0xffff;
  75
  76 // kRtcpCastLastPacket is used in PacketIDSet to ask for
  77 // the last packet of a frame to be retransmitted.
  78 const uint16 kRtcpCastLastPacket = 0xfffe;
  79
  80 const size_t kMinLengthOfRtcp = 8;
  81
  82 // Basic RTP header + cast header.
  83 const size_t kMinLengthOfRtp = 12 + 6;
  84
  85 // Each uint16 represents one packet id within a cast frame.
  86 // Can also contain kRtcpCastAllPacketsLost and kRtcpCastLastPacket.
  87 typedef std::set<uint16> PacketIdSet;
  88 // Each uint8 represents one cast frame.
  89 typedef std::map<uint8, PacketIdSet> MissingFramesAndPacketsMap;
  90
  91 // TODO(pwestin): Re-factor the functions bellow into a class with static
  92 // methods.
  93
  94 // January 1970, in NTP seconds.
  95 // Network Time Protocol (NTP), which is in seconds relative to 0h UTC on
  96 // 1 January 1900.
  97 static const int64 kUnixEpochInNtpSeconds = INT64_C(2208988800);
  98
  99 // Magic fractional unit. Used to convert time (in microseconds) to/from
 100 // fractional NTP seconds.
 101 static const double kMagicFractionalUnit = 4.294967296E3;
 102
 103 // The maximum number of Cast receiver events to keep in history for the
 104 // purpose of sending the events through RTCP.
 105 // The number chosen should be more than the number of events that can be
 106 // stored in a RTCP packet.
 107 static const size_t kReceiverRtcpEventHistorySize = 512;
 108
 109 inline bool IsNewerFrameId(uint32 frame_id, uint32 prev_frame_id) {
 110   return (frame_id != prev_frame_id) &&
 111          static_cast<uint32>(frame_id - prev_frame_id) < 0x80000000;
 112 }
 113
 114 inline bool IsNewerRtpTimestamp(uint32 timestamp, uint32 prev_timestamp) {
 115   return (timestamp != prev_timestamp) &&
 116          static_cast<uint32>(timestamp - prev_timestamp) < 0x80000000;
 117 }
 118
 119 inline bool IsOlderFrameId(uint32 frame_id, uint32 prev_frame_id) {
 120   return (frame_id == prev_frame_id) || IsNewerFrameId(prev_frame_id, frame_id);
 121 }
 122
 123 inline bool IsNewerPacketId(uint16 packet_id, uint16 prev_packet_id) {
 124   return (packet_id != prev_packet_id) &&
 125          static_cast<uint16>(packet_id - prev_packet_id) < 0x8000;
 126 }
 127
 128 inline bool IsNewerSequenceNumber(uint16 sequence_number,
 129                                   uint16 prev_sequence_number) {
 130   // Same function as IsNewerPacketId just different data and name.
 131   return IsNewerPacketId(sequence_number, prev_sequence_number);
 132 }
 133
 134 // Create a NTP diff from seconds and fractions of seconds; delay_fraction is
 135 // fractions of a second where 0x80000000 is half a second.
 136 inline uint32 ConvertToNtpDiff(uint32 delay_seconds, uint32 delay_fraction) {
 137   return ((delay_seconds & 0x0000FFFF) << 16) +
 138          ((delay_fraction & 0xFFFF0000) >> 16);
 139 }
 140
 141 inline base::TimeDelta ConvertFromNtpDiff(uint32 ntp_delay) {
 142   uint32 delay_ms = (ntp_delay & 0x0000ffff) * 1000;
 143   delay_ms >>= 16;
 144   delay_ms += ((ntp_delay & 0xffff0000) >> 16) * 1000;
 145   return base::TimeDelta::FromMilliseconds(delay_ms);
 146 }
 147
 148 inline void ConvertTimeToFractions(int64 ntp_time_us,
 149                                    uint32* seconds,
 150                                    uint32* fractions) {
 151   DCHECK_GE(ntp_time_us, 0) << "Time must NOT be negative";
 152   const int64 seconds_component =
 153       ntp_time_us / base::Time::kMicrosecondsPerSecond;
 154   // NTP time will overflow in the year 2036.  Also, make sure unit tests don't
 155   // regress and use an origin past the year 2036.  If this overflows here, the
 156   // inverse calculation fails to compute the correct TimeTicks value, throwing
 157   // off the entire system.
 158   DCHECK_LT(seconds_component, INT64_C(4263431296))
 159       << "One year left to fix the NTP year 2036 wrap-around issue!";
 160   *seconds = static_cast<uint32>(seconds_component);
 161   *fractions = static_cast<uint32>(
 162       (ntp_time_us % base::Time::kMicrosecondsPerSecond) *
 163           kMagicFractionalUnit);
 164 }
 165
 166 inline void ConvertTimeTicksToNtp(const base::TimeTicks& time,
 167                                   uint32* ntp_seconds,
 168                                   uint32* ntp_fractions) {
 169   base::TimeDelta elapsed_since_unix_epoch =
 170       time - base::TimeTicks::UnixEpoch();
 171
 172   int64 ntp_time_us =
 173       elapsed_since_unix_epoch.InMicroseconds() +
 174       (kUnixEpochInNtpSeconds * base::Time::kMicrosecondsPerSecond);
 175
 176   ConvertTimeToFractions(ntp_time_us, ntp_seconds, ntp_fractions);
 177 }
 178
 179 inline base::TimeTicks ConvertNtpToTimeTicks(uint32 ntp_seconds,
 180                                              uint32 ntp_fractions) {
 181   int64 ntp_time_us =
 182       static_cast<int64>(ntp_seconds) * base::Time::kMicrosecondsPerSecond +
 183       static_cast<int64>(ntp_fractions) / kMagicFractionalUnit;
 184
 185   base::TimeDelta elapsed_since_unix_epoch = base::TimeDelta::FromMicroseconds(
 186       ntp_time_us -
 187       (kUnixEpochInNtpSeconds * base::Time::kMicrosecondsPerSecond));
 188   return base::TimeTicks::UnixEpoch() + elapsed_since_unix_epoch;
 189 }
 190
 191 inline base::TimeDelta RtpDeltaToTimeDelta(int64 rtp_delta, int rtp_timebase) {
 192   DCHECK_GT(rtp_timebase, 0);
 193   return rtp_delta * base::TimeDelta::FromSeconds(1) / rtp_timebase;
 194 }
 195
 196 inline uint32 GetVideoRtpTimestamp(const base::TimeTicks& time_ticks) {
 197   base::TimeTicks zero_time;
 198   base::TimeDelta recorded_delta = time_ticks - zero_time;
 199   // Timestamp is in 90 KHz for video.
 200   return static_cast<uint32>(recorded_delta.InMilliseconds() * 90);
 201 }
 202
 203 }  // namespace cast
 204 }  // namespace media
 205
 206 #endif  // MEDIA_CAST_CAST_DEFINES_H_