One of the “It’s not going to be perfect” issues emerging with the rollout of HD voice on wireless networks is the ability to transcode between AMR-WB — the current “standard” for mobile HD codecs — and G.722, the de facto HD voice standard on broadband and enterprise networks.
Last week at the HD Communications Summit, Thomas Lemaire, Director of Business Development at France Telecom/Orange said that initially there would be no direct way to transfer HD calls between its broadband and mobile domains.
The problems moving between universes lies in the different codec approaches and processing, with “more aggressive” compression schemes such as AMR-WB providing less information for a transcoding session into G.722; on the other hand, moving from G.722 to AMR-WB appears to be less problematic.
Exactly “bad” a call transcoded from AMR-WB into G.722 might sound to a G.722 caller hasn’t been quantified by vendors, but there is an unsaid implication that an AMR-WB transcoded voice stream will sound “less good” to a G.722 caller than a native G.722 session. Will it be better than a PSTN session piped into G.722? Vendors are reluctant to quantify exactly will come out until they have more experience with all the moving parts.