If a message is sent between CDMA and GSM networks, where does transcoding occur?
Because CDMA and GSM carriers may use different codecs (e.g. CDMA QCELP vs. GSM AMR speech codecs), MMS message content may need to be adapted to the appropriate format before delivery to a recipient user in a different network. This adaptation from one codec to another is known as transcoding and may be implemented as follows: • Generally speaking, the recipient MMSC is responsible for content adaptation to an appropriate format for the recipient user device. As such, MMSC servers in both CDMA and GSM networks should have the capability to transcoding between common codecs used in both networks and should perform this transcoding when necessary • Alternatively, carriers may have agreements established between one another that require MMS messages to adhere to specifically defined formats.
