Witbe measures a worldwide channel change time below 1.9 seconds

Tuesday, October 7th, 2008 
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Channel change time and image quality are central to TV service suppliers in today’s competitive market

PARIS, La Défense — With its unique QoE monitoring technology*, 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. Still 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 (eg Cisco VQE), can degrade the quality.

This study also allowed qualification of service availability (black screen or error screens, sound but no image, image but no sound etc) the image quality as well as sound quality.

*dedicated to measuring delivered quality of TV services out of the set-top box.