HDTV Forum

Can anyone explain why it is that there are more technical problems with picture & sound when HDTV is combined with DD5.1.

Some recent examples ...

WGN HD ... Everwood began with an HDTV picture but no sound (my receiver indicated Dolby Digital). Near the end of the opening segment WGN switched to 4:3 SDTV. At about 10 minutes past the hour they switched back to HDTV with DD5.1 and there were no further problems.

ABC Seattle (KOMO4) ... tried to show the movie "Saving Private Ryan" in HDTV with DD5.1. For half an hour there were almost continual picture and sound dropouts and picture freezes. Finally KOMO4 gave up and switched to SDTV with prologic sound.

Although the problems with DD5.1 are not as bad as in the beginning, they still occur. Why? What makes HDTV combined with DD5.1 such a challenge?

Thanks.

My guess, and it's only a guess, is digital audio is like digital video. Once you get a drop of any level it will cut out. Audio pixelating one might call it. I've noticed in my area that the PBS HD station is the worst at audio drop outs. If some channels are perfect and others are spotty, whose fault is it, the carrier or the programmer? Does Directv or cable assign different amounts of bandwidth to various stations or are they all equal?

Hi,
Another guess, this is probably not a KOMO issue as I have never experienced dropouts from them, but it could be the size of the pipe your provider is making available. If it is a KOMO issue, they wer having trouble "for a while" with digital transmission from their provider and switched to analog until it could be fixed.

DD5.1 and 1080i are digital, Dolbyprologic and 4/3 480i are analog.

Theres all kinds of weird things that only engineers can explain and even then they would probably say it could be one of several things.

Peter m.