Supported audio codecs in Zoiper3

Zoiper 3 supports the following audio codecs:

• GSM

• Speex

• ITU G.711 (PCMU/PCMA) Comes in two flavors: a-law and mu-law.

• iLBC20

• iLBC30

• ITU G.729 *

Supported video codecs:

Zoiper 3 supports the following video codecs:

• H264

• VP8

Wideband codecs

Zoiper 3 does not support wideband codecs. They are available in Zoiper 5 and as in-app purchases in our mobile products. 

Required bandwidth

What bandwidth is required depends on what audio codec is used.
Rough list of audio codec requirements (sending and receving):

• GSM - 13.2 Kbps (full rate)
• iLBC - 15.2 Kbps, 20ms frame size: 13.33 Kbps, 30ms frame size
• ITU G.711 (PCMU/PCMA)- 64 Kbps
• ITU G.729 - 8 Kbps *
• Speex - 2.15 to 44.2 Kbps receiving and fixed to 15 Kbps when transmitting.

* Note that G.729 is available only in the Biz version of Zoiper 3.

Re-ordering of the selected codecs.

To re-order your selected codecs list, go to Settings -> Accounts -> select your account and click on the Codec tab.

Use the arrows or drag and drop to move the codec to the desired position.

Available codecs: lists all available, but currently not enabled codecs.

Enabled codecs: lists all currently enabled codecs.

Which codec will be used first?

It depends if Zoiper answers or offers the codecs. If Zoiper answers, it will always select the first supported codec from the offer. Zoiper can not force a codec selection.

Example:

If a server offers g729 and a-law in this order, Zoiper will stick to the server's choice of g729, even if a-law has higher priority in Zoiper's list.

If Zoiper offers the codecs, it will offer them in the order specified in its configuration. Still, the server can decide to enforce g729, in which case Zoiper will use it.