> For the complete documentation index, see [llms.txt](https://prosbcdocs.telcobridges.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://prosbcdocs.telcobridges.com/telecom-references/parameter-reference/transcoding.md).

# Transcoding parameters

Codecs, vocoders and companding. 6 parameters.

## A

| Parameter                   | Description                                                                                                                                                              |
| --------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| **Allow audio transcoding** | Allow audio codec transcoding when the joined call legs have incompatible codecs, or when IVR functions are required (tone detection, tone play, file play, file record) |
| **Audio Companding**        | Audio companding on this line service (aLaw, uLaw or automatic based on stack variant).                                                                                  |
| **Audio Transcoding Type**  | Transcoding can be used to convert the media encoding type, for example from G.711 to G.729.                                                                             |

## C

| Parameter                 | Description                                                                                                                                        |
| ------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Codecs selection mode** | This controls which codecs are offered to call legs: \*All codecs: Keep all codecs in the SDPs, including those only known by one of the two legs. |

## F

| Parameter                                            | Description                                                                                                                                                 |
| ---------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Force Transcoding for Telephony Event Conversion** | This parameter forces the transcoding for telephony event conversion, when one of two joined call legs does not support the telephony event (DTMF RFC2833). |

## P

| Parameter                              | Description                                                                                               |
| -------------------------------------- | --------------------------------------------------------------------------------------------------------- |
| **Packet Network: SSRC randomization** | Enable the randomization of SSRC when the RTP stream is restarted (codec change or other similar reason). |


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