# Codec Settings

## Purpose

Use this form to filter the list of audio codec(s) negotiated by devices at each end of a call within the MiVoice Business network. Filtering removes the codec from the call negotiation offer and can be used, for example, in a bandwidth-managed network to favor the selection of non-compression codecs (e.g., G.711) over compression codecs (G.729) for better voice quality.

NOTE: Mitel has implemented the G722.1 CODEC using a 32Kbit bitrate. Any third-party device or application must support this bitrate to inter-operate with MiVoice Business. A device or application attempting to use G722.1 with a different bitrate will experience audio problems. To overcome the incompatiblity, do one of the following,

1. Disable the G722.1 CODEC globally on MiVoice Business using this form. However, this means that the CODEC cannot be used by any device (including IP sets) connected to MiVoice Business.

2. If the third party device/application is connected to MiVoice Business via SIP trunks, set "Renegotiate SDP To Enforce Symmetric Codec" to Yes in the SIP Peer Profile of the device/application in question.

3. If the third party device/application is connected to us as a SIP phone, set the same option as in Option 2 but this time in the SIP Device Capabilities form for the incompatible device.

## Conditions

- Codec filtering does not apply to IP Trunks as they behave as media proxies.

- G.711a and G.711u codecs cannot be filtered; both are always offered for negotiation.

- GSM FR and AMR Narrowband codecs can be negotiated only when both endpoints support them and are connected to MiVoice Business through a SIP Client Interface or a SIP trunk. TDM endpoints, E2T connections, Mitel sets, or Mitel applications do not support audio streams in these codecs.

- For Hot desking, the codec filter settings applied are those of switch hosting the hot desk user not the switch where registration DN is programmed.

- Adding a codec filter results in a warning maintenance log.

## Field Descriptions

Parameter | Description | Default Value
G.711a Filtered | Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it. | No
G.711u Filtered | Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it. | No
G.722 Filtered | Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it. | No
G.722.1 Filtered | Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it. | No
G.723 Filtered | Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it. | No
G.723.1c Filtered | Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it. | No
G.728 Filtered | Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it. | No
G.729a Filtered | Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it. | No
G.729b Filtered | Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it. | No
T.38 Filtered | Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it. | No
AMR Narrowband Filtered | Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it. | Yes
GSM FR (06.10) Filtered | Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it. | Yes
OPUS Filtered | Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it. | No

Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it.

Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it.

Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it.

Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it.

Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it.

Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it.

Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it.

Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it.

Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it.

Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it.

Select "Yes" to filter (remove) the codec from the negotiation offer or "No" to keep it.