Cisco Unity Troubleshooting Guide (With Lotus Domino), Release 4.0(2) - Audio Quality [Cisco Unity]

Table Of Contents

Audio Quality

About Audio Quality Problems

Audio Quality Problems in Cisco Unity

Set Volume Level Utility

Advanced Audio Quality Troubleshooting in Cisco Unity

Cisco Unity Is G.729a Capable

Set Record Format

Cisco Unity-CM TSP Wave Gain Utility

Automatic Gain Control

Cisco Unity Automatic Gain Control and Registry Settings

Dialogic Voice Card Automatic Gain Control and Registry Settings

Comfort Noise

Audio Troubleshooting Utilities

AudioStat

CAP Ripper

RTP Parser

Audio Quality

About Audio Quality Problems

Audio quality problems can manifest themselves in a variety of ways, and can be difficult to diagnose and correct. For example, subscribers may report volume differences between messages and system prompts, or report that messages are distorted. Audio quality symptoms may not be present for every subscriber, or consistently appear on every message or every system prompt.

The entire device topology can affect audio quality, both within and outside of the control of Cisco Unity. Cisco Unity-controlled features include automatic gain control (AGC), the Cisco Unity-CM TSP wave gain, and the audio codec chosen for message storage. Cisco CallManager controls the region setting for the audio codec. Finally, the Cisco gateway gain and attenuation settings can also affect audio quality.

Audio Quality Problems in Cisco Unity

The most common symptom of audio quality problems in Cisco Unity is when the volume of greetings and voice names is higher or lower than the volume of Cisco Unity prompts.

See Table 6-1 for basic corrective action to level all WAV files on the Cisco Unity server to the same value, and to adjust the playback level if needed.

Table 6-1 Basic Audio Quality Troubleshooting for Cisco Unity

Symptom

General Circumstances

Corrective Action

The volume of greetings and voice names is higher or lower than the volume of Cisco Unity prompts.

Only certain greetings and voice names may be affected, and/or an upgrade to version 3.1(3) or later was recently done.

1. Confirm that the Cisco Unity-CM TSP wave gain playback and record settings are both set to 0.

2. Run the Set Volume Level utility to bring pre-upgrade greetings and voice names to the correct dB levels.

3. Check and adjust the Cisco Unity AGC settings, if necessary (set to -26 dB default value).

4. Check and adjust the Cisco Unity-CM wave gain playback setting, if necessary.

For detailed instructions, see the "Set Volume Level Utility" section.

For upgrades from 3.1(2) to 3.1(3) or to 3.1(4), refer to http://www.cisco.com/warp/public/788/AVVID/white_noise.html.

Set Volume Level Utility

The Set Volume Level utility allows you to level all WAV files on the Cisco Unity server to the same value, and to adjust the playback level, if needed.

Because automatic gain control is enabled by default in Cisco Unity version 3.1(2c) and later, systems upgraded to 3.1(2c) and later may experience a problem in which the existing greeting and name recordings sound louder than new greetings and names recorded after the upgrade.

In Cisco Unity version 3.1(4), a new registry setting, AGCminimumThreshold, was added to control the minimum dB level of an incoming recording that Cisco Unity attempts to adjust. The setting prevents both silence in a message and background hiss from being adjusted. The AGCminimumThreshold has a default setting of -45 dB and an allowable range of -35 dB to -55 dB.

To maximize success in resolving or avoiding volume problems, we recommend that you first upgrade to Cisco Unity version 3.1(4) or later, then use the Set Volume utility to match the existing greeting and name recordings to the gain levels of Cisco Unity after the upgrade.

Confirm that you have the latest version of the Set Volume utility by doing the procedure To Download and Install the Latest Version of the Set Volume Utility.

The procedure To Adjust Greeting and Name Recordings by Using the Set Volume Utility, levels all WAV files on the Cisco Unity server to the same value, and provides instructions for adjusting the playback level, if necessary.

To Download and Install the Latest Version of the Set Volume Utility

Step 1 Browse to the Software Center website at http://www.cisco.com/public/sw-center/sw-voice.shtml.

Step 2 Under Cisco Unity Software, click Cisco Unity Utilities.

Step 3 Compare the version of the file SetVolume.zip in the table to the Set Volume utility version on the Cisco Unity system.

Step 4 If the version in the table is later than the version currently installed on the system, download the file SetVolume.zip.

Step 5 Specify a directory to which the files will be downloaded.

Step 6 In Winzip, double-click Setup.exe.

Step 7 Click OK.

Step 8 Click Change Directory, and browse to the directory CommServer\Utilities\VolumeAdjust.

Step 9 Follow the on-screen instructions to complete the installation.

To Adjust Greeting and Name Recordings by Using the Set Volume Utility

Step 1 Exit the Cisco Unity Administrator.

Step 2 On the Cisco Unity server desktop, double-click the Cisco Unity Tools Depot icon.

Step 3 If you do not have a Cisco CallManager integration, skip to Step 5.

If you have a Cisco CallManager integration, and the Cisco CallManager region is set to use the G.711 codec, in the left pane, under Administrative Tools, double-click Wave Gain.

Step 4 Confirm that both Record Gain and Playback Gain are set to 0.

Step 5 In the left pane of the Tools Depot window, browse to Audio Management Tools, and double-click Set Volume.

Step 6 In the Set Greetings and Voice Names window, click Select All.

Step 7 Confirm that the Save Original Files check box is checked, then enter the location to which the backup copy of the original recorded names and greetings files will be saved.

Step 8 In the Options section, verify the values shown in the following table. Note that only Cisco Unity versions 3.1(4) and later have the Min. dB Threshold registry setting referred to here.

New Target dB

-26

Sample Size

8000

Max dB Adjustment

5

Min. dB Threshold

-45

Step 9 Confirm that the Save Above Volume Options check box is checked. Note that setting New Target dB to a value other than zero turns on automatic gain control.

Step 10 Click Set Volume Level.

Step 11 When "Done" appears in the Set Volume window, all existing greeting and name recordings have been adjusted to the New Target dB level. Click OK, and then click Exit.

Step 12 If you do not have a Cisco CallManager integration, you have completed all necessary steps in this procedure.

If you have a Cisco CallManager integration, and the Cisco CallManager region is set to use the G.711 codec, start the Cisco Unity Administrator.

Step 13 Go to any page in the Cisco Unity Administrator that contains a Media Master control bar, and verify that the phone is selected as the playback device.

Note In order to use the phone as a recording and playback device, Cisco Unity must have at least one port designated TRAP Connection per session on the System > Ports page. See the "Voice Messaging Port Settings" section in the Cisco Unity System Administration Guide for more information. This guide is available at http://www.cisco.com/en/US/products/sw/voicesw/ps2237/products_administration_guide_books_list.html.

Step 14 Click Play on the Media Master control bar to listen to a recording (for example, a subscriber greeting) over the phone.

If the volume of the recording is acceptable, you have completed all necessary steps in this procedure.

If the volume of the recording is too quiet, continue with Step 15.

Step 15 In the left pane of the Tools Depot window, under Audio Management Tools, double-click Wave Gain.

Step 16 Increase the Playback Gain value by one or two dB. Listen to the volume of a recording.

If the volume of the recording is acceptable, note the Playback Gain value and continue with Step 17.

If the volume of the recording is still too quiet, repeat this step.

Step 17 In the left pane of the Tools Depot window, under Administrative Tools, double-click Advanced Settings Tool.

Step 18 In the Unity Settings pane, click Set Wave Gain dB Adjustment for Playback.

Step 19 Enter the new value determined in Step 16, and click Set.

Step 20 When prompted, click OK. You do not need to restart the Cisco Unity server to enable the registry change.

Step 21 Click Exit.

Advanced Audio Quality Troubleshooting in Cisco Unity

See Table 6-2 for advanced corrective actions and links to other troubleshooting procedures and information for the following symptoms:

•Messages and/or Cisco Unity prompts sound distorted.

•A hissing sound is heard when there is no audio from Cisco Unity.

•Message playback volume is higher or lower than the volume of Cisco Unity prompts, in special cases.

•Callers can hear Cisco Unity prompts, but Cisco Unity does not transmit any audio when a caller speaks.

For more information, refer to the White Paper: Audio Codecs and Cisco Unity, available on Cisco.com at http://www.cisco.com/en/US/products/sw/voicesw/ps2237/prod_technical_reference_list.html.

For additional advanced audio troubleshooting tools, see the "Audio Troubleshooting Utilities" section.

Note than unless otherwise specified, all procedures apply to Cisco Unity version 3.1(4) and later.

Table 6-2 Advanced Audio Quality Troubleshooting

Symptom

General Circumstances

Corrective Action

Messages and/or Cisco Unity prompts sound distorted.

You are using the G729a codec for message storage and retrieval.

1. Confirm that Cisco Unity is capable of receiving G.729a streams. See the "Cisco Unity Is G.729a Capable" section.

2. Confirm that the G.729a codec is being used for message recording on Cisco Unity. See the "Set Record Format" section.

3. Confirm that the Cisco CallManager region is set to G.729a. Refer to the applicable Cisco CallManager Administration Guide, available on Cisco.com at http://www.cisco.com/en/US/products/sw/voicesw/ps556/prod_instructions_guides.html.

4. Confirm that the Cisco Unity G.729a prompts are installed. Refer to the CiscoUnity3.1.G729aPrompts.Readme, available on the Software Center download website at http://www.cisco.com/public/sw-center/sw-voice.shtml.

You are using the G.711 codec for message storage and retrieval.

Confirm that the Cisco CallManager region is set to G.711. Refer to the applicable Cisco CallManager Administration Guide, available on Cisco.com at http://www.cisco.com/en/US/products/sw/voicesw/ps556/prod_instructions_guides.html.

Hissing noise is heard when there is no audio from Cisco Unity, such as between system prompts or during transfers.

You are using IP phones.

Check the Cisco Unity comfort noise registry setting. See the procedure To View and Adjust the Cisco Unity Comfort Noise Registry Setting.

For upgrades from 3.1(2) to 3.1(3) or to 3.1(4), refer to http://www.cisco.com/warp/public/788/AVVID/white_noise.html.

Message playback volume is higher or lower than the volume of Cisco Unity prompts, in special cases.

Only outside caller messages are affected on a Cisco Unity system version 3.1(2b) and earlier.

1. Check the Cisco gateway gain and attenuation levels. Refer to the guide for your gateway, available on Cisco.com at http://www.cisco.com/univercd/cc/td/doc/product/voice/c_access/index.htm.

2. Check the Cisco Unity-CM TSP wave gain playback and record settings. See the "Cisco Unity-CM TSP Wave Gain Utility" section.

Both subscriber and outside caller messages are affected system-wide on a Cisco Unity system version 3.1(2b) and earlier.

Check the Cisco Unity-CM TSP wave gain playback and record settings. See the "Cisco Unity-CM TSP Wave Gain Utility" section.

Cisco Unity plays system prompts but does not transmit voice.

Cisco Unity may have a dual NIC misconfiguration.

See the "Cisco Unity Plays System Prompts but Does Not Transmit Voice" section.

Cisco Unity Is G.729a Capable

When the registry setting HKEY_LOCAL_MACHINE\Software\Active Voice\AVSkinny\G729 Enabled is set to 1, it means that Cisco Unity is capable of receiving both G.729a streams and G.711 streams. It does not indicate that G.729a is in use for message storage. This is the default setting for Cisco Unity version 3.1(x) systems. Because the G.729a codec is installed automatically with version 4.0(1) and later, this registry setting is no longer needed.

To Confirm that Cisco Unity Is Capable of Receiving G.729a Streams (Version 3.(x) Only)

Step 1 Start Regedit.

Caution Changing the wrong registry key or entering an incorrect value can cause the server to malfunction. Before you edit the registry, confirm that you know how to restore it if a problem occurs. (Refer to the "Restoring" topics in Registry Editor Help.) If you have any questions about changing registry key settings, contact Cisco TAC.

Step 2 If you do not have a current backup of the registry, click Registry > Export Registry File, and save the registry settings to a file, then close Regedit.

Step 3 Expand the registry key

HKEY_LOCAL_MACHINE\Software\Active Voice\AVSkinny\G729 Enabled.

Step 4 Confirm that the Value is set to 1.

Step 5 If you changed the value in Step 4, click OK. You do not need to restart the Cisco Unity server to enable the registry change.

Set Record Format

The Set Record Format utility changes the codec used for all recordings on Cisco Unity. It is not possible to select user or port-specific recording formats. Changes to the record format apply only to recordings made after the change takes place. The utility does not convert any existing messages or greetings to the new codec.

If a Cisco Unity system has been running for a while and the codec is then changed, Cisco Unity may have greetings, voice names, prompts and messages stored in more than one format. Cisco Unity can transcode between formats; however, mixed message formats on very busy version 3.(x) systems have been known to cause the problem described in caveat CSCae08069. For more information, and for a workaround for the problem, refer to http://www.cisco.com/warp/public/788/AVVID/reorder_tone_after_startup.htm. Contact Cisco TAC before installing the workaround.

To view codec information for greetings, voice names, and prompts, do the procedure To View Codec Information for Greetings, Voice Names, and System Prompts.

To change the codec used for all Cisco Unity recordings (messages, greetings, and voice names) do the procedure To Change the Cisco Unity Recording Codec.

For information on choosing and implementing codecs, refer to the White Paper: Audio Codecs and Cisco Unity, available on Cisco.com at http://www.cisco.com/en/US/products/sw/voicesw/ps2237/prod_technical_reference_list.html.

To View Codec Information for Greetings, Voice Names, and System Prompts

Step 1 On the Cisco Unity desktop, double-click the Cisco Unity Tools Depot icon.

Step 2 In the left pane of the Tools Depot window, under Audio Management Tools, double-click Codec Checker.

Step 3 To export the data to a CSV file, click File, then choose to export either greeting and voice name data or prompt data.

Step 4 Click Exit.

To Change the Cisco Unity Recording Codec

Step 1 Exit the Cisco Unity software (right-click the Cisco Unity icon in the system tray, then click Stop Cisco Unity).

Step 2 To use the G.711 Mu-law or A-Law, G729a, or GSM 6.10 codec, skip to Step 4.

Step 3 To use one of the optional Dialogic OKI ADPCM codecs:

a. Browse to the Software Center website at http://www.cisco.com/public/sw-center/sw-voice.shtml
Click Other Components under Cisco Unity.

b. Click CiscoUnityDialogicCodec.exe, and download the file to the directory of your choice on the Cisco Unity server.

c. Unzip the CiscoUnityDialogicCodec.exe file to the directory of your choice.

d. Double-click Avvox_setup.exe, and follow the on-screen prompts.

Step 4 On the Cisco Unity desktop, double-click the Cisco Unity Tools Depot icon.

Step 5 In the left pane, under Audio Management Tools, double-click Set Record Format.

Step 6 In the Format list, select a supported codec, and click OK.

Step 7 Restart the Cisco Unity server.

To Change the Recording Format for Existing Greetings and Voice Names

Step 1 On the Cisco Unity desktop, double-click the Cisco Unity Tools Depot icon.

Step 2 In the left pane, under Audio Management Tools, double-click Set Wav Format.

Step 3 Select the greetings and voice names to adjust.

Step 4 Under Backup Original Voice Names and Greetings, check the check box, and enter the location to save the original files.

Step 5 On the list, select the new Wav format.

Step 6 Click Set Wav Format.

Step 7 Click OK, then click Exit.

Step 8 Restart the Cisco Unity server.

Cisco Unity-CM TSP Wave Gain Utility

The registry keys shown in Table 6-3 determine how the Cisco Unity-CM TSP adjusts record and playback volume for all recordings (messages, prompts, voice names, and greetings) for IP devices in a Cisco CallManager region that contains Cisco Unity and is set to use the G.711 codec.

These registry settings are only applicable with a Cisco CallManager integration. If you have a PBX integration that uses Dialogic voice cards, see the "Dialogic Voice Card Automatic Gain Control and Registry Settings" section.

Use the Wave Gain utility to adjust and test the WaveDBGainPlayback and WaveDBGainRecord levels. The record and playback settings determined by using the Wave Gain utility must be manually entered into the registry by using either the Advanced Settings Tool or Regedit.

Table 6-3 Wave Gain Utility Registry Keys

Key Name

Purpose

Recommended Setting

WaveDBGainPlayback

Controls the wave driver boost or the reduction of system-wide playback levels for all recordings.

0—When Cisco Unity automatic gain control (AGC) is enabled. This value may be changed if necessary after adjustments are made to the AGC setting.

0xfffffff6 (the default)—version 3.0(x) and earlier systems where Cisco Unity AGC is not present.

WaveDBGainRecord

Controls the wave driver boost or the reduction of recordings system-wide.

0—When AGC is enabled.

5 (the default)— version 3.1(2b) and earlier systems where AGC is not present.

For Cisco Unity versions 3.1(2c) and later, set both the Cisco Unity-CM TSP Wave Gain record and playback levels to 0 to begin the volume adjustment process. If you have not already done so, do the procedure To Adjust Greeting and Name Recordings by Using the Set Volume Utility.

If Cisco Unity automatic gain control is not present (version 3.1(2b) and earlier systems only), the Cisco Unity-CM TSP Wave Gain playback level setting alone can be adjusted as needed for best sound quality, one or two dB at a time, by doing the following procedure.

To Determine the Optimum Cisco Unity-CM TSP Wave Gain Settings (Cisco Unity Version 3.1(2b) and Earlier Only)

Step 1 Start Regedit.

Caution Changing the wrong registry key or entering an incorrect value can cause the server to malfunction. Before you edit the registry, confirm that you know how to restore it if a problem occurs. (Refer to the "Restoring" topics in Registry Editor Help.) If you have any questions about changing registry key settings, contact Cisco TAC.

Step 2 If you do not have a current backup of the registry, click Registry > Export Registry File, and save the registry settings to a file, then close Regedit.

Step 3 Browse to the CommServer\Utilities directory.

Step 4 Double-click Wave Gain.

Step 5 To increase the playback volume, enter a positive number in the Playback Gain field. To decrease the playback volume, enter a negative number in the field. Do not adjust the value by more than one or two dB.

Step 6 Confirm that Record Gain is set to 0. Do not change this setting to a value other than 0.

Step 7 Leave a message for a test subscriber.

Step 8 Log on to Cisco Unity and listen to the test subscriber message.

Step 9 If you are not satisfied with the volume of the test subscriber message, repeat Step 5 as necessary.

Step 10 When you are satisfied with the volume of the test subscriber message, write down the recording and playback volume settings, which you will enter into the registry in the following procedure To Update Wave Gain Settings in the Registry for Cisco Unity Version 3.1(2b) and Earlier.

To Update Wave Gain Settings in the Registry for Cisco Unity Version 3.1(2b) and Earlier

Step 1 On the Cisco Unity server desktop, double-click the Cisco Unity Tools Depot icon.

Step 2 In the left pane, under Administrative Tools, double-click Advanced Settings Tool.

Step 3 In the Unity Settings pane, click the wave gain adjustment registry key to be edited.

Step 4 Enter a new value, as recorded in Step 9 of the preceding procedure, and then click Set.

Step 5 When prompted, click OK.

Step 6 Click Exit.

Step 7 Restart the Cisco Unity server for the registry change to take effect.

Automatic Gain Control

Cisco Unity Automatic Gain Control and Registry Settings

Cisco Unity automatic gain control (AGC) gives subscribers consistent message playback levels through the normalization of recordings. AGC affects recordings only. It is on by default, is controlled by registry settings, and is applied to voice samples after they have passed through all external hardware.

AGC does not improve the quality of recordings; it only addresses volume issues. For example, it cannot improve garbled incoming messages.

Because automatic gain control is enabled by default in Cisco Unity version 3.1(2c) and later, systems upgraded to 3.1(2c) and later may experience a problem where the existing greeting and name recordings sound louder than new greetings and names recorded after the upgrade. To prevent or resolve this problem after an upgrade, use the Set Volume utility to match the existing greeting and name recordings to the gain levels of Cisco Unity after the upgrade.The default values for the registry settings should be used for all Cisco Unity version 3.1(2c) and later upgrades. If you have not already done so, do the procedures in the "Set Volume Level Utility" section.

If you are using Dialogic voice cards, Cisco Unity AGC should be turned on, and the recommended settings for AGC in Table 6-4 are applicable.

The registry keys shown in Table 6-4 determine how Cisco Unity AGC normalizes recordings.

Table 6-4 Automatic Gain Control Registry Keys

Key Name

Purpose

Recommended Setting

AGCtargetDB

Target root mean square (RMS) power to which all recordings are normalized.

The setting is system-wide.

-26 dB.

The accepted range is -18dB to -30dB.

A setting of 0 (zero) disables AGC.

AGCsampleSize

Buffer sample size used to calculate the average RMS power level.

8000.

AGCuseCompression

Determines if a sample is clipped when a gain adjustment is applied. A value of 1 will not clip the sample; 0 clips the sample to the minimum/maximum values.

1.

(0 = clipped sample; disables compression).

AGCgainThreshold

Maximum dB gain (+/-) applied to a sample to bring it to the target dB level.

5 dB.

AGCminimumThreshold

Controls the minimum dB level of an incoming recording that Cisco Unity attempts to adjust. The setting prevents silence in a message and background hiss from being adjusted.

-45 dB.

The accepted range is -35 dB to -55 dB.

To Disable Cisco Unity AGC

Step 1 Exit the Cisco Unity Administrator.

Step 2 On the Cisco Unity server desktop, double-click the Cisco Unity Tools Depot icon.

Step 3 In the left pane of the Tools Depot window, browse to Audio Management Tools, and double-click Set Volume.

Step 4 In the Set Greetings and Voice Names window, click Select All.

Step 5 Confirm that the Save Original Files check box is checked, then enter the location to which the backup copy of the original recorded names and greetings files will be saved.

Step 6 In the Options section, set New Target dB to 0 (zero).

Step 7 Confirm that the Save Above Volume Options check box is checked. Note that setting New Target dB to a value other than zero turns on automatic gain control.

Step 8 Click Set Volume Level.

Step 9 When "Done" appears in the Set Volume window, all existing greeting and name recordings have been adjusted to the New Target dB level with AGC disabled.

Step 10 Click OK, and then click Exit.

Dialogic Voice Card Automatic Gain Control and Registry Settings

Dialogic voice cards adjust the volume of recorded messages by using their own on-board AGC. Adjusting the playback volume for all recordings on systems equipped with Dialogic voice cards is done by changing the Median Volume registry setting. This setting is also used in the case of a dual integration, when you want to change the output volume level on the PBX side without affecting the Cisco CallManager side.

Cisco Unity AGC should also be enabled on systems with Dialogic voice cards.

To Adjust the Playback Volume of Recordings for Cisco Unity Systems Equipped with Dialogic Voice Cards

Step 1 Start Regedit.

Caution Changing the wrong registry key or entering an incorrect value can cause the server to malfunction. Before you edit the registry, confirm that you know how to restore it if a problem occurs. (Refer to the "Restoring" topics in Registry Editor Help.) If you have any questions about changing registry key settings, contact Cisco TAC.

Step 2 If you do not have a current backup of the registry, click Registry > Export Registry File, and save the registry settings to a file.

Step 3 Using Regedit, expand the registry key

HKEY_LOCAL_MACHINE\Software\Active Voice\Miu\1.0.\Initialization\ServiceProvider<n>\ MedianVolume

where <n> is either 0 for a single switch, or 1 for a dual switch configuration. Expand the setting applicable to your configuration to select the PBX switch. Do not select the Cisco CallManager switch.

Step 4 In the Base window, click Decimal.

The default setting for analog voice cards is 50, and the accepted range is between 0 and 100. Note that this setting is not in decibels, and that the numerical values are not linear. For example, a setting of 100 is louder, but not twice as loud as 50. Make a small adjustment to this setting of no more than 10 units louder or quieter.

Step 5 To adjust the playback volume for Text to Speech recordings (TTS), browse to the Median TTS Volume key.

Step 6 In the Base window, click Decimal.

The default setting for analog voice cards is 50, and the accepted range is between 0 and 100. Like the Median Volume key, this setting is not in decibels, and the adjustments are not linear. Make a small adjustment to this setting of no more than 10 units louder or quieter.

Step 7 Restart the Cisco Unity server.

Step 8 Test the playback levels of several recordings. If the volume levels are acceptable, you have completed all steps necessary in this procedure. If the volume levels are too high or too low, repeat Step 3 through Step 7, and retest until you are satisfied with the results.

Comfort Noise

Comfort noise is low-level background noise generated on a IP device. Its purpose is to simulate the hiss produced in a circuit-switched connection, and it can be generated when there is no audio from Cisco Unity, for example, during a transfer or between system prompts.

Comfort noise is not sent over the network, and is audible only on the IP device that receives a comfort noise generation packet. Comfort noise generation packets are sent by Cisco Unity when it is integrated with Cisco CallManager, and when the HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Avaudio\Parameters\ComfortNoise registry setting is enabled.

The Cisco Unity ComfortNoise registry setting controls the ability of Cisco Unity to send comfort noise generation packets to an IP phone, or to a gateway that is enabled to receive and respond to comfort noise generation packets. This registry setting does not affect comfort noise generation on a call between two IP phones. Cisco Unity also does not respond to comfort noise generation packets sent by other devices. These packets are treated as silence at the wave driver level.

If subscribers hear an audible hissing noise when there is no audio from Cisco Unity, and if it is judged to be too loud a noise, confirm that the Cisco Unity comfort noise registry setting is enabled (set to a value other than zero), and adjust the setting to a lower value as needed. The default value set during the Cisco Unity-CM TSP install is -50dB.

Note The registry setting for Cisco Unity comfort noise does not reflect the minus sign, so a registry setting of 50 is actually -50dB.

There will always be some amount of hissing noise between prompts. The Cisco Unity ComfortNoise registry setting only tells the IP phone or gateway how loud that hiss should be. A value of zero causes the IP phone or gateway to use its default hiss level.

To View and Adjust the Cisco Unity Comfort Noise Registry Setting

Step 1 Start Regedit.

Caution Changing the wrong registry key or entering an incorrect value can cause the server to malfunction. Before you edit the registry, confirm that you know how to restore it if a problem occurs. (Refer to the "Restoring" topics in Registry Editor Help.) If you have any questions about changing registry key settings, contact Cisco TAC.

Step 2 If you do not have a current backup of the registry, click Registry > Export Registry File, and save the registry settings to a file.

Step 3 Expand the registry key

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Avaudio\Parameters\ComfortNoise.

Step 4 In the Edit Dword Value window, click Decimal.

Step 5 Modify the Cisco Unity comfort noise setting as needed:

•To decrease the volume of background noise between prompts and other audio, increase the setting (for example, to 60 dB). Make small adjustments to this setting of no more than 10 units.

•To increase the volume of background noise, reduce the setting (for example, to 40 dB). Make small adjustments to this setting of no more than 10 units.

•To disable Cisco Unity comfort noise, set the value to 0.

Step 6 Click OK.

Step 7 Restart the Cisco Unity server.

Audio Troubleshooting Utilities

The following advanced audio utilities are available in Cisco Unity version 4.0(2) and later—in the CommServer\Utilities\Audio directory—and can be used to troubleshoot audio problems.

Caution We recommend using these tools only with Cisco TAC supervision.

AudioStat

The AudioStat utility allows audio driver statistics to be viewed in real time. The information provided by the AudioStat utility can help isolate audio quality issues caused by packet delay and codec-related problems.

Click the Global and Record Log tabs to display information, as shown in Table 6-5 and Table 6-6.

Table 6-5 AudioStat Utility Global Tab

Field Name

Description

G711 Packets

G729 Packets

Number of incoming and outgoing G.711 and G.729a RTP packets.

Note that packets are constantly being received, even if a recording is not in progress.

Other Packets

Number of other types of RTP packets sent and received, such as AVT tones or unknown audio formats received.

Out of Sequence

Number of packets received out of sequence.

RTP Header Errors

Number of RTP headers that were invalid.

Exceeded Silence Threshold

Usually indicates that silence was inserted by the audio driver, due to a missing packet.

Note that a missing packet does not necessarily mean that there is a network issue. Some IP devices may not send any audio packets when the audio that would otherwise be sent is silence.

Playback Count and Record Count

Number of playbacks and recordings.

Table 6-6 AudioStat Utility Record Log Tab

Field Name

Description

Device

Audio device number used for the recording.

Time

Time that the recording started.

Avg (ms)

Average time between packets (in milliseconds).

Src IP

Src Port

Source IP address and port of the recording (for example, IP phone or gateway).

Local Port

UDP port number used by Cisco Unity for the recording.

Duration

Length of the recording (in seconds).

CAP Ripper

The CAP Ripper utility extracts RTP audio from .cap files created by Sniffer Pro or Network Monitor.

Network Monitor (also known as NetMon) is a utility that comes with Microsoft Systems Management Server and Microsoft Windows 2000 Server. You use NetMon to capture and observe network traffic patterns and problems. For information on using NetMon, refer to the Microsoft Knowledge Base Article Q294818, available on the Microsoft Product Support website.

The CAP Ripper utility creates .wav files for each unique IP source and destination.

To Extract Audio by Using the CAP Ripper Utility

Step 1 Create a .cap file containing RTP audio by using NetMon or Sniffer Pro.

Step 2 Copy the .cap file to the \CommServer\Utilities\Audio directory on the Cisco Unity server.

Step 3 At a command prompt, browse to the \CommServer\Utilities\Audio directory, and enter capripper <name of .cap file>.

For example, enter capripper capture1.cap.

Wav file output is generated for each unique IP source/destination combination. For example:
Creating 10.93.248.235(31640) to 10.93.248.227(22818).wav
Creating 10.93.248.227(22816) to 10.93.248.235(31640).wav
Step 4 Use the -s option to provide additional troubleshooting information about timing delays and sequencing of packets. For example, enter capripper -s capture1.cap.

The output shows detailed information from each of the .wav files. For example:
10.93.248.235(31640) to 10.93.248.227(22818).wav
RTP packets processed 275
Start seq 4881  End seq 5155
Format g729a
No packets out of sequence
Avg. time between packets 20.03ms
Longest packet delay 20ms
Total frames in .cap file 1433
Step 5 If you receive the error message "No voice RTP packets found" when attempting to extract audio from a .cap file, verify that the capture file you are working with contains RTP packets.

If you are using a NetMon capture, and you are sure that the file contains RTP data, it may be possible that the starting offset of the capture data could not be determined. Use the -d option to view the binary data. For example, enter capripper -d netmon.cap.

A sample section of the output shows the following information:
000000A0  98 05 00 00 8D 7F 02 00 00 00 00 00 CE 01 00 00     ................
000000B0  00 00 00 00 00 00 00 00 29 04 00 00 00 00 00 00     ........).......
000000C0  FF FF FF FF FF FF FF FF 00 00 00 00 FF FF FF FF     ................
000000D0  FF FF FF FF 00 00 00 00 C8 4A 02 00 00 00 00 00     .........J......
000000E0  3C 00 00 00 3C 00 00 00 FF FF FF FF FF FF 00 02     <...<...........
000000F0  A5 07 2A 18 08 06 00 01 08 00                       ..*.......
Step 6 To determine the starting offset, subtract 8 bytes from the first of two repeating DWORD values that you see in the .cap file. In the preceding example, the 3C value repeats on line E0. Note that the numbers in the file are in hex, and that there are 16 bytes displayed on each line. Eight bytes back from the first repeating DWORD value 0x3C is at 0x000000E0. Therefore, the starting offset of the first packet is
0xE0 - 8 = 0xD8 or 216.

Step 7 Indicate the starting offset obtained in Step 6 with the -o option. For example, enter capripper -o 216 netmon.cap.

The output will show the delay and packet sequencing information.

RTP Parser

The RTP Parser add-on can be used to expand NetMon capability to decode RTP packets when viewing capture files in real time, or when viewing saved .cap files.

Network Monitor (also known as NetMon) is a utility that comes with Microsoft Systems Management Server and Microsoft Windows 2000 Server. You use NetMon to capture and observe network traffic patterns and problems. For information on using NetMon, refer to the Microsoft Knowledge Base Article Q294818, available on the Microsoft Product Support website.

To Install the RTP Parser

Step 1 Copy the RtpParser.dll file from the CommServer\Utilities\Audio directory to the Winnt\System32\Netmon\Parsers directory on the Cisco Unity server.

Step 2 Restart NetMon.

To View a Capture File by Using the RTP Parser

Step 1 Create a .cap file containing RTP audio by using NetMon.

Step 2 View the .cap by file using NetMon Capture Summary View.

Step 3 Double-click on a frame row in the Summary View to see the RTP Parser View.