BBC HD New Encoder?

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  • grahamlthompsongrahamlthompson Posts: 18,486
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    mwardy wrote: »
    Cool link--thx.

    I agree fascinating reading :D
  • White-KnightWhite-Knight Posts: 2,508
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    What the STB and display can do often makes whatever the artefact is appear worse ... and often very different from the orignal Transmitted error -if any.

    This makes the job of finding out what is happening rather difficult - and that is assuming that the display is set up correctly... e.g. not excessive sharpness or Saturated colours.

    In my experience there is usually something which (eventually) you can track down as the trigger but how visable this is on another display (or CRT) is often marginal.
    ... and this is in a world where I have the material on a stream recorder ... so can loop the "error".

    It was bad enough on MPEG 2 - MPEG4AVC has a different set of issues which seem to confuse some upscalers/ deinterlacers.

    Don't know if this helps but my TV's calibrated to THX standards using a THX II reference disc (dedicated set up disc not extras on a film). So i know my settings are spot on.
  • dansusdansus Posts: 2,559
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    Watched Dragons Den Ep7 in HD and it looks pretty good.

    The median is higher than before, so the new algorithm is doing something good, but it lacked that last bit of bite in sharpness compared to previous encodes which is common with the latest encoders that claim better for less.
  • jzeejzee Posts: 25,498
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    dansus wrote: »
    Watched Dragons Den Ep7 in HD and it looks pretty good.

    The median is higher than before, so the new algorithm is doing something good, but it lacked that last bit of bite in sharpness compared to previous encodes which is common with the latest encoders that claim better for less.
    I don't think any encoder maker would claim that BBC could get the same quality with nearly half what was the previous bitrate, to get the same quality they need to go up to at least 12Mbps, either fixed rate or the higher level of a stat muxed rate.
  • [Deleted User][Deleted User] Posts: 306
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    BBC HD have effectively given up on HD. No better now than a picture on a good CRT.

    Unfortunately if you want real HD, you have to pay for it via Sky.
  • [Deleted User][Deleted User] Posts: 429
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    bfg20 wrote: »
    BBC HD have effectively given up on HD. No better now than a picture on a good CRT.

    Unfortunately if you want real HD, you have to pay for it via Sky.

    The BBC HD feed on sky is the same as the one on Freesat tho, so why would paying for it on sky be any better?
    You're just forking out money to get the same poor image
  • [Deleted User][Deleted User] Posts: 306
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    Sky Sports etc which are excellent.

    If you were watching only BBC HD on Sky it would be a waste of money.

    The BBC are effectively broadcasting a sub HD service and getting away with it at the moment.
  • White-KnightWhite-Knight Posts: 2,508
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    Planet Earth was poor again tonight. In some scenes you could see extremely prominent grain.
  • [Deleted User][Deleted User] Posts: 4,237
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    Widget76 wrote: »
    The BBC HD feed on sky is the same as the one on Freesat tho, so why would paying for it on sky be any better?
    You're just forking out money to get the same poor image
    BBC HD is free on Sky, you don't have to pay for it. The point is that if you pay for Sky's subscription HD channels, you get high quality pictures at a respectable bitrate - obviously not on the BBC, but on the paid channels which know that they live or die by the quality of their pictures. Unlike the current half resolution / low-bitrate channels being offered up on Freesat.
  • [Deleted User][Deleted User] Posts: 116
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    bignoise wrote: »
    The point is that if you pay for Sky's subscription HD channels, you get high quality pictures at a respectable bitrate

    Like the 5mbit movie channels...
  • BKMBKM Posts: 6,912
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    kunkie wrote: »
    Like the 5mbit movie channels...
    Exactly which ones might those be?????
  • jzeejzee Posts: 25,498
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    kunkie wrote: »
    Like the 5mbit movie channels...
    Apologies for defending Sky here:rolleyes:, but their HD movie channels average 9-10Mbps- movie channels actually need less bitrate overall as with all non 16:9 movies compression savings can be made in the black bar areas.
  • IncastIncast Posts: 1,590
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    jzee wrote: »
    Apologies for defending Sky here:rolleyes:, but their HD movie channels average 9-10Mbps- movie channels actually need less bitrate overall as with all non 16:9 movies compression savings can be made in the black bar areas.

    The key reason is that films are progressive rather than interlaced. Although broadcast in 1080i, the actual frames will contain no interlacing and it is much easier for the encoders to compress.

    This is called 2:2 pulldown; more information is on the wiki at http://en.wikipedia.org/wiki/Telecine#2:2_pulldown
  • scoobiesnacksscoobiesnacks Posts: 3,055
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    Incast wrote: »
    The key reason is that films are progressive rather than interlaced. Although broadcast in 1080i, the actual frames will contain no interlacing and it is much easier for the encoders to compress.

    This is called 2:2 pulldown; more information is on the wiki at http://en.wikipedia.org/wiki/Telecine#2:2_pulldown

    Very interesting.

    So what in your opinion is the correct bitrate level required for a HD film channel?

    Maybe naively I thought Sky movies was broadcasting at quite low bitrate levels compared to Sports. I realise Sports is live encoded and needs more movement, but I still thought it quite low if you look at something like Sky HD Action Movies which I think is around 6-7 mbps.

    I should add I don't have Sky so can't comment on their quality.
  • jzeejzee Posts: 25,498
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    Incast wrote: »
    The key reason is that films are progressive rather than interlaced. Although broadcast in 1080i, the actual frames will contain no interlacing and it is much easier for the encoders to compress.

    This is called 2:2 pulldown; more information is on the wiki at http://en.wikipedia.org/wiki/Telecine#2:2_pulldown
    Quite a bit of content on BBC HD is the same in not having interlaced frames, it's not just films. The black bars do make it easier to compress- with a 2.35:1 or 1.33:1 film formatted in a 16:9 frame, 1/4 of the screen is black.
  • White-KnightWhite-Knight Posts: 2,508
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    Some screen shots (photos using a camera) showing the grain from Planet Earth - unbelievably bad even by SD standards never mind HD.

    I actually get the feeling some of this is SD despite the BBC saying they don't use SD in HD programmes. Even so, if it was, given their vast library of Natural History footage I find it difficult to believe they couldn't find better footage to insert than this. Poor production at its worst:

    3 of the worst shots (hard to believe this is a HD channel!):

    TO VIEW AT FULL SIZE, CLICK "FULL SIZE" ICON BELOW THE PICTURE. THIS THEN OPENS IT IN A NEW WINDOW.

    THEN CLICK ONCE MORE ON THE PICTURE IN THE NEW WINDOW AND IT SHOULD ZOOM TO 100%.

    Warning: Full Size is nearly 3000 x 2000 pixels (not re-sized so as to leave the grain viewable)

    Cheetah: http://yfrog.com/0c65367965j

    Smoke (pic cropped (but NOT Enlarged)to concentrate on smoke / chimney area): http://yfrog.com/0c48437747j

    Jungle (in rain but grain clearly visible): http://yfrog.com/0c48013654j
  • grahamlthompsongrahamlthompson Posts: 18,486
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    Some screen shots (photos using a camera) showing the grain from Planet Earth - unbelievably bad even by SD standards never mind HD.

    I actually get the feeling some of this is SD despite the BBC saying they don't use SD in HD programmes. Even so, if it was, given their vast library of Natural History footage I find it difficult to believe they couldn't find better footage to insert than this. Poor production at its worst:

    3 of the worst shots (hard to believe this is a HD channel!):

    TO VIEW AT FULL SIZE, CLICK "FULL SIZE" ICON BELOW THE PICTURE. THIS THEN OPENS IT IN A NEW WINDOW.

    THEN CLICK ONCE MORE ON THE PICTURE IN THE NEW WINDOW AND IT SHOULD ZOOM TO 100%.

    Warning: Full Size is nearly 3000 x 2000 pixels (not re-sized so as to leave the grain viewable)

    Cheetah: http://yfrog.com/0c65367965j

    Smoke (pic cropped (but NOT Enlarged)to concentrate on smoke / chimney area): http://yfrog.com/0c48437747j

    Jungle (in rain but grain clearly visible): http://yfrog.com/0c48013654j

    how did you get 3000 x 2000 pixels from 1440 x 1080 without resampling ? Ah i see you used a digital camera, not really valid as this introduces its own problems (moire etc). A camera setting as close as possible to the screen pixel (as near 1:1 pixel mapping as possible) would be more convincing

    A better way is to record unencrypted and then use vlcplayer to grab a frame giving you the actual pixels

    One from the old encoder

    http://www.4shared.com/file/87140911/18a9e873/HDpreview00001.html
  • [Deleted User][Deleted User] Posts: 2,190
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    I actually get the feeling some of this is SD despite the BBC saying they don't use SD in HD programmes.
    The BBC is allowed to put in up to 25% of SD to allow for showing "archived footage" etc., in an HD programme.

    Rgds.

    Les.
  • White-KnightWhite-Knight Posts: 2,508
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    They taken from off the screen using an 8mb pixel camera.

    8mb is actually 3264 x 2448 but I cropped them to remove the surrounding wall.
  • White-KnightWhite-Knight Posts: 2,508
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    savvy wrote: »
    The BBC is allowed to put in up to 25% of SD to allow for showing "archived footage" in an HD programme.

    Rgds.

    Les.

    There was some archived footage elsewhere Les, and that could possibly be used to explain the chimney smoke shot if old footage was used, but how do you explain away the cheetah and rain in the jungle shots? the BBC has extensive natural history libraries in both SD and HD and I've never seen such poor grain ridden shots before in my life. I find it hard to believe there was nothing better than this in their libraries in SD nevermind HD, and thats assuming it was old footage.

    Also, check out the BBC HD logo on those shots, its just as poor as the picture itself.
  • u006852u006852 Posts: 7,283
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    I have just seen that ITV are to start broadcasting 6 regional ITV1+1 channels.

    Considering the space issues on 2D I sincerely hope that this has nothing to do with the bitrate cut.
  • grahamlthompsongrahamlthompson Posts: 18,486
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    Screen grab of HD Test Card using new encoder

    http://www.4shared.com/file/129351821/a9c96fea/HDpreview00006.html


    Anyone got the same from the old encoder for comparison
  • u006852u006852 Posts: 7,283
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    Screen grab of HD Test Card using new encoder

    http://www.4shared.com/file/129351821/a9c96fea/HDpreview00006.html


    Anyone got the same from the old encoder for comparison

    I haven't but I do have recordings on my Humax HDR of old and new and no obvious difference is noticeable.

    I can still see the 25 and circa 26MHz gratings just the same.

    However a static image is a not a good way to compare old and new encoders.

    Its the way it handles the motion/changes in the picture thats important and many other variables such as how the noise reduction is working.

    Offscreen photos so not an appropriate way to judge the picture quality, darker than reality for one thing, just for example.

    http://picasaweb.google.co.uk/lh/photo/ya2hfeTRc5xNFojnxMGLcQ?feat=directlink

    http://picasaweb.google.co.uk/lh/photo/ZDzSF7Z7n8oTmx62DTFP7Q?feat=directlink
  • ProbablyMikeProbablyMike Posts: 173
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    Hi,

    Very new to anything HD having got my Humax Freesat+ box about 3 weeks ago, and disappointed to find that the BBC are cutting back on the quality.

    Obviously can't comment on the picture before the new low bandwidth, but noticed something very bad on one of the BBC HD idents, the one where kids are fishing.

    Just as the fade at the end starts the water all changes colour for a split second, looks like when saving a photo as a .gif image with 256 colours.
  • grahamlthompsongrahamlthompson Posts: 18,486
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    u006852 wrote: »
    I haven't but I do have recordings on my Humax HDR of old and new and no obvious difference is noticeable.

    I can still see the 25 and circa 26MHz gratings just the same.

    However a static image is a not a good way to compare old and new encoders.

    Its the way it handles the motion/changes in the picture thats important and many other variables such as how the noise reduction is working.



    I agree of course but the above discussions involved a digital photo of a paused frame as justification of the poor performance of the new encoder. Even less valid in my opinion at least the pixels are the original and not processed by the camera software.
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