RTC Core Layer and SIP protocol keys
Port manager related keys
Key Path:
HKLM\Comm\\RTC\\PortRange
Key Value(s)
Key Value Type
Description
Enabled
DWORD
Enables Port range as defined by subsequent port key values
MinSipDynamicPort
MaxSipDynamicPort
Used for setting the port range for SIP signaling traffic.
MinMediaPort
MaxMediaPort
Used for setting the port range for audio/video RTP and RTCP traffic.
Qos Related Keys
HKLM\Comm\\RTC\\QoS
Disabled
When = 1, disables setting of DSCP field in IP header and layer 2 tagging. By default DSCP QoS is On
DSCPSIP
Defines the DSCP index value to be used for SIP packets. By default, DSCPAudio (index 5) is used. DSCPAudio corresponds to 0x38 in IP DSCP/TOS field.
SIP protocol related keys
HKLM\Comm\\RTC
MinExpiresTimeoutinSec
Lets user set the minimum expiry time in sec, that is allowable by RTC. Any value lower than the value set in this registry (or default 19 sec when not set) from the server will be rejected.
The registry is settable in the range of 5 to 9999999
Media Stack
Devices
Key path:
HKLM\Comm\RTC\DeviceSettings
DeviceSSMode
If set to 0, will disable silence suppression and all audio packets, including silence will be transmitted during an audio call.
DeviceAudioSamplingFrequency
Should be set either to 8000 or 16000. This registry lets the devices to be opened either using 8K or 16K sampling frequency. By default devices are opened at 8K sampling frequency. Opening devices at 16K will cause increase in network bandwidth as more audio samples are sent over the network. CPU consumption also increases as more samples are processed by the media stack and AEC module (if enabled). However, audio quality also increases when 16K samples are used.
DisableAGC
If set to 1, it disables AGC (Auto Gain Control in RTC)
Media Stack Performance Tuning
HKLM\Comm\RTC\Threads
EngineThreadsPriority
Lets user change the priority at which media stack thread is running (default is 221). Acceptable value is between 1 and 255. Caution should be used in changing the default priority as this may impact the way audio data is captured and rendered and may also affect other components running on the system.
TimerFrequency
Lets user set the polling time period for the RTC media engine stack. Default is set to 5 msec (value 50000). Registry is settable between values 10000 (1 msec) and 1000000 (100 msec)
OverlappedSend
If set to 0, will disable overlappedSend and used blocking send for WinSock sockets. This may increase processing time of the media stack thread.
TransportThreadsPriority
Lets user change the priority at which media stack transport thread is running (default is 221). Acceptable value is between 1 and 255. Caution should be used in changing the default priority as this may impact the way media data is processed and may also affect other components running on the system.
Media Stack QoS
HKLM\Comm\RTC\QoS
DSCPAudioRTP
Defines the DSCP index value to be used for Audio RTP packets. By default, DSCPAudio (index 5) is used. DSCPAudio corresponds to 0x38 in IP DSCP/TOS field.
DSCPAudioRTCP
Defines the DSCP index value to be used for Audio RTCP packets. By default, DSCPAudio (index 5) is used. DSCPAudio corresponds to 0x38 in IP DSCP/TOS field.
Media Stack NAT work around
HKLM\Comm\RTC\NAT
EnableEarlyUDPPackets
When set to 1, enables sending Early UDP packets on RTP and RTCP ports, whenever RTC stack detects a change in remote address/port. This enables opening of ports on a NAT, incase RTC client is behind one. This way, traffic from the remote client can be received through the NAT.
Media Stack in-band DTMF
HKLM\Comm\RTC\DTMF
InBandDTMFToneGap
This lets user set the time gap that RTC should introduce between sending 2 in-band DTMF tones. The default value is 250msec and the reg key is settable in msec between 100 and 1000.
DisableOOBDTMFPlayback
This lets user disable playback of Out of Band DTMF events. By default, RTC media stack plays back these events with the corresponding DTMF tones
OOBDTMFPlaybackDuration
This key controls the duration of the OOB DTMF tone playback. This accepts value between 10 and 500 msec. By default, tones played back are of 200 msec.
Media Stack Pluggable Codec
HKLM\Comm\RTC\Codec
UseSirenAndG7221
Activates use of Siren and G7221 codec inside of RTC. By default, these 2 codecs are turned off as they are floating point based and may not be suitable for ARM based devices.
UsePreferredCodec
If set to 1, it enables preferred codec logic. A codec can be made preferred by setting this key and setting the reg key PreferredAudioCodec to the payload number of the codec, that needs to be made preferred
PreferredAudioCodec
If set to a codec payload number, along with setting UsePreferredCodec to 1, makes the respective codec as the preferred codec. This ensures that RTC will select the respective codec over other codecs, if the remote party supports the preferred codec. Setting this key also causes RTC to list that codec as the first codec, in the SDP.
HKLM\Comm\RTC\ ACM
<Codec Name>
Sub-Key
Each key Under HKLM\Comm\RTC\ACM
Denotes a pluggable codec e.g.
HKLM\Comm\RTC\ACM\GSM can be used for GSM610 codec.
HKLM\Comm\RTC\ACM\<Codec Name>
PayloadType
Denotes playload type
FrameDuration
Denotes frame duration in msec
CodecRank
Denotes the rank of the codec
UseHealer
Indicates weather internal RTC audio healing should be used for this codec or not. By default it is not used.
Driver
String
Indicates the dll name that implements the codec.
HKEY_LOCAL_MACHINE\Comm\RTC\ACM\<Codec Name>\WaveFormat
FormatTag
Denotes format tag
Channels
Number of channels that the codec supports.
SamplesPerSec
Denotes samples per sec that the codec supports.
AvgBytesPerSec
Denotes Avg. Bytes per sec
BlockAlign
Block Align
BitsPerSample
Bite Per Sample
bSize