there more than one byte per sample of voice can be used, which is the standard used in G.711 codec in PSTN (at the analogue/digital conversion of voice at the user terminal in mobile networks or home gateways/IP phones in fixed networks), which should provide higher QoE for voice services than PSTN (of course, this requires higher bitrates per voice connection end-to-end, which gives a lower number of connections being served with the same bandwidth). This calculation refers to both OTT VoIP and operator's VoIP; however, in the case of operator's VoIP the changes in codecs are less likely to be frequent while for OTT voice services (where the same application is present on both ends of the connection) such change can be more easily provided than with operator's VoIP. So, in cases where Internet bandwidth (end-to-end) is high, OTT VoIP may provide even higher QoE than operator's VoIP (e.g. for fixed access or for nomadic users in the case of mobile access). 6.2 QoS-enabled Video and IPTV Services Video is the most demanding type of traffic on the Internet and managed IP networks. Around two-thirds of all IP traffic (around 2020), including Internet and managed 6 Services in Fixed and Mobile Ultra-Broadband Table 6.1 Main video resolutions and respective bitrates (for display aspect ratio 16:9). Video picture Bitrate per TV resolution stream (user's Video type (pixels X lines) side) (Mbit/s) SD (standard definition) 720 X 576 (for PAL) 1.5-5 720 X 480 (for NTSC) HD (high definition) 1280 X 720 Full HD 1920 X 1080 4K-UHD (4K ultra HD) 3840 X 2160 15-40 8K-UHD (8K ultra HD) 7680 X 4320 20-100 PAL/SECAM is the analogue TV standard in Europe, while NTSC is the analogue TV standard in the Americas. IP networks, comes from video traffic, including OTT video and QoS-enabled video and IPTV. So, the development of broadband and ultra-broadband speeds in the access networks (fixed and mobile) contributes to better user experience with all different services and applications, but particularly with video services. Why? Becaus