Advanced Television

Witbe: channel change average is 1.9 secs

October 16, 2008

Channel change time and image quality are central to TV service suppliers in today's competitive market. Witbe carried out a study of digital TV services (via DSL, cable, FTTH,

satellite and DTT), looking at 30 operators in 16 countries on 4 continents. The average channel change time measured using P+/P- was 1.9 seconds. If the user chooses the channel number,

the change time came out at 3.4 seconds with a more uniform distribution than in P+/P- mode.

Witbe noted important variations between operators but also between technologies.

Witbe distinguished amongst these factors:

– The broadcasting technology: satellite is twice as slow as IPTV

– The maturity of the services tested: services launched recently are often slightly slower

– The IPTV system used: for example, Microsoft Mediaroom platforms have the best results in P+/P- mode, with an average of 0.6 seconds. Channel change times of 0.7 seconds can be measured on other platforms.

– The performance of the decoder and notably the buffering policy

– The presence of retransmission mechanisms or forward error correction which, when they are not

combined with rapid channel change systems, can degrade the quality

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