sound quality). The other codecs used are AMR-WB+ that can create more multiple audio programs as well as limited multimedia can also be broadcast, as with HD Radio and DAB. The available broadcasting bandwidth for digital audio varies from 40 kbit/s while sharing the space with existing analog signals, or 156 kbit/s if all analog signals (except the base monophonic signal) are dropped. (For comparison, iBiquity's Hybrid Digital/analog system offers 100-150 kbit/s in shared mode, and 300 kbit/s in pure digital mode.) The coverage is similar to FM Stereo, and therefore high ERP is required in larger urban areas, as with normal FM transmissions. Digital Radio Express has since gone out of business, after a brief stretch where it rebranded itself as VuCast in an effort to emphasize the technology's datacasting capabilities. Choosing a standard North American FM bands are separated by 200 kHz while only using about 50 kHz for a high-quality stereo broadcast. This leaves significant amounts of unused spectrum between the channels. This unused spectrum led the FCC to strongly favor some sort of in-band standard for the digital transition. This is in contrast to European systems which use a similar amount of bandwidth for FM signals but typically separate the channels only 100 MHz. European stations favored moving to entirely new channels for digital broadcasts to avoid interfering with their existing FM signals. Two systems were evaluated during the late 1990s, FMeXtra and HD Radio. From a purely technical perspective, HD Radio was more advanced than FMeXtra, using newer compression and encoding to allow the signals to be flexibly allocated into the existing channels. FMeXtra normally added a single 48 kbps digital channel carried in the 62.5-98.5 kHz area of the channel (just above the audio signal). HD Radio offered several different modes that used up more of the empty spectrum, providing 96 to 120 kbps. FMeXtra allowed one stream of "good" quality, two medium, or four mono low-quality signals suitable for talk radio. HD Radio offered one high-fidelity signal, better than FM, or several mixtures of medium quality. Although HD Radio had superior technical capabilities (largely by using more bandwidth), FMeXtra was dramatically easier to implement. In the most common use-case, the existing FM signal would be fed into an FMeXtra encoder and then sent directly to the existing transmitter systems. The company did not charge any licensing, the only cost was the encoder box