Freeview bitrates

Discussion in 'Freeview & YouView' started by Voiceedit, Mar 8, 2006.

  1. Voiceedit

    Voiceedit
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    I've just searched this section of the Forum for threads about the bitrates used on Freeview channels. There appears to be a need for a concerted effort to do something about this because although there are some references to bitrates they are scattered, so here goes!
    Assuming a good signal strength there is clear evidence that the bitrate varies considerably between channels.
    BBC channels appear OK as does ITV-1 but others vary with Five and Sky-3 being the worst I've observed so far. The effect of a low bitrate is what I call "rubber face". A close up of a face has large areas of the screen (eg cheeks) of a similar texture. Presumably a low bitrate can use a very low coding for such an area. If the face moves slightly (as it will always do!) then the cheek area, for example, stays still with the rest of the face moving around it. This gives a "Wallace and Gromit" like effect to the face which is why I call it "rubber face". At its worst a mole, for example, in the centre of the cheek will be coded once and then repeated in successive frames in the same position. As the face then shifts slightly that mole can appear to travel all round the cheek because it's actually staying on the same pixels on the screen.
    I believe it is not acceptable to foist such appalling artefacts on the public. It is arrogant in the extreme for the providers of these channels to assume the public won't notice - we shall!! With the analogue switch-off on the horizon and HD in the foreground it's time to "get it right" with regard to standard definition tv. Who agrees?
    Incidentally, why does Channel 4 digital from the Rowridge transmitter suffer from appalling drop-outs on Sunday afternoons? I've had to resort to analogue to watch "Enterprise" - fortunately it's presented in 16:9 letterbox on that platform. Oh, and who at Five thought it was acceptable to present "The Forbidden Planet" in 4:3 the other day?
     
  2. PhilipL

    PhilipL
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    Hi

    I know exactly what you mean and it is very distracting! I have also noticed this effect (yes you are quite correct in your explanation as to why it happens) and you are one of the few other people I have ever seen mention it.

    The "extra" channels use a lower resolution and lower bit rate, so can and do look a lot worse. A good example is "Supernatural" advertised for and on ITV2, we started watching it and noticed the rubber faces plus the really annoying and distracting logo and were going to give up watching it. Then we found it by accident being repeated on ITV1 several days behind and started watching that and the difference is amazing. No rubber faces and no annoying logo and the extra detail (pores on peoples faces) was noticeable from the off, although still room for improvement if they gave it a bit more bandwidth. If a program/series is repeated on the main 5 even if it is a week or more behind we watch the repeat rather than be patronised by stupid logos and poor quality.

    The only thing we can do is complain to the TV companies and the government or through local MPs. However most people don’t seem to care about the picture quality, it is only “quantity” that counts these days for a large percentage of people, just look at MP3 players and horribly compressed music that sounds worse than cassette tape did gaining popularity because they hold hundreds of hours of music. With ITV having increased profits, expect a further reduction in quality as they plan to add more channels!

    Regards

    Phil
     
  3. Starburst

    Starburst
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    Yeah I was amazed to see that Supernatural on ITV2 was only using a little over 1gig of hard drive space on my Humax, the lower resolution and bitrate explains that:)
     
  4. jaymac

    jaymac
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    None of that compareswith the bit rate on Dab the uk has the lowest in the world
     
  5. Andy3

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    Voiceedit, you have described it perfectly and you are not alone. I find 'rubberface' or 'plasticface' as I call it very unsettling. I don't get this effect on SkyDigi, which is what I watch most of the time.
    Some people on this forum swear by Freeview and insist its pictures are better than Sky, but the rubberface effect is too much to bear!
     
  6. M271

    M271
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    I think that TV companies will have to make sure that the PQ is OK otherwise people will switch over and advert revenue will fall.

    As more people get flat screen Tvs that highlight the problems more poor PQ will reflect poorly on the TV companies.

    I find that since I have got an LCD TV that I watch more channel 5, films and documentary programmes because normally the PQ is better on these.
     

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