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sky digital picture quality

Discussion in 'Sky Digital TV Forum' started by puc, Jul 23, 2002.

  1. puc

    puc
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    Has anyone else noticed that different channels on Sky digital appear to be of varying quality? I recently bought a Philips widescreen to replace a 21" set and was a little disappointed with the RGB picture quality from Sky.

    Some channels (esp E4) seem to have tiny pixcels visible which gives a "raining" effect, others (BBC1) seem to be a little grainy compared to DVD and some (Sky News) seem to give a great picture.

    I'd be interested to hear other users opinions.
     
  2. Starburst

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    Every channel on the SKY D platform is transmitted at a different bitrate which will affect the quality of the picture, lots of screen area taken up with static images (News) will give a better picture when compared to a high motion program when both are transmitted at similar bitrates.
    However be aware that every TV handles the SKY RGB output differently and then adds it's own processing onto the picture, the result can vary alarmingly from TV to TV.
    Do not expect to get DVD quality images from any domestic digital TV service, yes they can be very good but DVD's are mastered by trained proffesionals who make the decisions on compression frame by frame unlike digital TV which is done on the fly by computers.

    I can only offer my opinions on the picture quality of SKY D when it's viewed on my own TV (41" 4:3 50hz RPTV).
    It's excellent once allowances are made for those channels that run on low bitrates or rely to heavily on multiplexing (Sharing capacity between channels dynamically).
     
  3. Lex

    Lex
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    What frustrates me is that really dull channels get decent bitrates and channels like 'Q' which I want to listen to up load is terrible quality. :(
     
  4. Dr.Magus

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    Sky News and some of the BBC channels don't look as good on my tosh widescreen set, however, film 4 and the documentary channels look great.

    I've only got basic scart cables though so i'm hoping to get some decent ones soon.

    Amen.
     
  5. Doubledoom

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    Over use of compression is a well discussed topic. Quite a lot of posts in the archive on this if you fancy the read back.
     
  6. Tejpal

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    that auction channel is broadcast in WIDESCREEN and look amazing!!!!!!!!!!!!!!!!!!!

    why dont they make all the channels look like that??
     
  7. Doubledoom

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    Studio shots would look better, even with fairly high compression as there is not much movement and big areas of the same colour.

    I know what you are getting at though. If skys auction channel can do it, why cant the others.
     
  8. Starburst

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    The idea that digital broadcasting is cheaper then analogue broadcasting is correct, most of the digital channels we have would no exist if it wasn't for digital TV.
    However when it comes to fianancing a channel the bean counters will always say paying X amount is too much can we get away with paying less and the cheapest way to reduce the cost of running a digital channel is to reduce the bandwidth.

    As you can see lower bitrate channels can look good when they broadcast a picture that has a high percentage of low/no motion images which means HIGH compression. A broadcast which has a lot of changes between frames can not get away with that and even when it uses more bandwidth it'll eventually hit a point where the cost is too much.
     

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