Any chance of 1080p25 on BBC HD on Freesat

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  • figrin_danfigrin_dan Posts: 1,437
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    If the data is the same, then so is the encode.
  • jzeejzee Posts: 25,498
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    Not interlaced 50 progressive.

    I understand most tv's can't show 50P because they lack the necessary processing power to handle 50 Progressive frames per second.
    Not true, we've discussed this before- all LCDs/Plasmas convert 50 field per second material to 50 fps, the deinterlacing processing creates the missing information between the field lines to create 50 frames.
  • Nigel GoodwinNigel Goodwin Posts: 58,329
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    jzee wrote: »
    Not true, we've discussed this before- all LCDs/Plasmas convert 50 field per second material to 50 fps, the deinterlacing processing creates the missing information between the field lines to create 50 frames.

    We might have discussed it before, but you still seem to be struggling to understand it?.

    A great many sets won't accept 1080P50 signals (particularly older ones), end of story really - there's nothing to debate about it.

    1080P50 isn't a requirement for HD Ready, and when the HD Ready specification was designed the technology wasn't really available for it. For a number of years only one Sony model was able to accept 1080P.
  • grahamlthompsongrahamlthompson Posts: 18,486
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    Even blu-ray won't do 1080p50
  • jzeejzee Posts: 25,498
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    We might have discussed it before, but you still seem to be struggling to understand it?.
    I haven't misunderstood anything:, you were the one that continued to insist on the older thread that even newer LCDs didn't convert 50 fields to 50 frames:rolleyes:.
  • figrin_danfigrin_dan Posts: 1,437
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    How do you propose to get the 50p signal to the panel?
  • Nigel GoodwinNigel Goodwin Posts: 58,329
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    jzee wrote: »
    I haven't misunderstood anything:, you were the one that continued to insist on the older thread that even newer LCDs didn't convert 50 fields to 50 frames:rolleyes:.

    I'm still trying to find out if that's the case or not, it's what you would expect the 100Hz models to do, and 100 fps for 200Hz models.
  • 2Bdecided2Bdecided Posts: 4,416
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    I'm still trying to find out if that's the case or not
    ...and then you'll move on to deciding whether you believe those people who claim the world is round? ;)

    Cheers,
    David.
  • 2Bdecided2Bdecided Posts: 4,416
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    Muzer wrote: »
    I was wondering if Freesat boxes support it...
    The answer to that at least is "yes" - freesat boxes are quite happy with 1080p25 H.264.

    I'm sure someone will keep an eye on the BBC HD satellite broadcasts to see if any genuine 1080p25 makes it way out via that route. Assuming separate encoders from Freeview HD, it won't unless they make a positive decision to change the software on the Freesat encoders too.

    From this...
    http://www.bbc.co.uk/blogs/researchanddevelopment/2011/04/software-upgrade-for-bbc-hd-on.shtml
    ...you've just got to hope that the software is very smart. There's a lot of hybrid content out there, though I suppose we should trust the BBC's encoders rather than our STBs and/or TVs.

    The thing is, the difference is really small. It's not going to stick out like a sore thumb unless the STB is stupid enough to base it's deinterlacing decisions entirely on this. E.g. if part of the picture is progressive, but part is interlaced (e.g. film with scrolling news ticker at the bottom, for example), then the STB needs to unpick that. The least bad "dumb" option is to treat it all as interlaced. The more likely scenario is for the BBC encoder to only use progressive when the whole image is 100% progressive, and for STBs and TVs to lock into progressive mode in this case, but drop back to standard/automatic otherwise.

    Cheers,
    David.

    P.S. @loz: I have no idea what Sky boxes do. Sorry.
  • White-KnightWhite-Knight Posts: 2,508
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    jzee wrote: »
    I haven't misunderstood anything:, you were the one that continued to insist on the older thread that even newer LCDs didn't convert 50 fields to 50 frames:rolleyes:.

    Even then you're interpolating.

    That's still different to accepting 50 progressive frames natively. Thats where the difference lies. Many tv's can't accept the bandwidth required through their inputs or process the information even if it could be received.

    Many manufacturers tvs from 2 or 3 years ago didn't support 50P except on the very top models and therein lies the problem for going over to 50P tv, because the majority of tv's bought in the last 10 years would not support the broadcasts.

    Only the very latest models and the very recent models do.

    BTW, the BBC used 50P / 100i cameras on the Freerunning Championships broadcast from London 2 years ago and the although the encoder had a few issues which we all pulled it up on via the BBC HD Forums, generally the picture was very good HD those encoding issues aside, and more tellingly despite a lot of very fast motion, there was no motion blur despite the subsequent down conversion to 50i. Therein lies the power of 50P / 100i.
  • 2Bdecided2Bdecided Posts: 4,416
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    Many manufacturers tvs from 2 or 3 years ago didn't support 50P except on the very top models and therein lies the problem for going over to 50P tv, because the majority of tv's bought in the last 10 years would not support the broadcasts.
    Nothing would support the broadcasts - even the "1080p50" Freeview STBs can't accept a 1080p50 broadcast signal.

    However, it would be trivial for new 1080p50 capable STBs to re-interlace the broadcasts to 1080i50 for legacy (!) TVs - just like current STBs down-convert HD to SD for SCART output.

    Cheers,
    David.
  • White-KnightWhite-Knight Posts: 2,508
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    2Bdecided wrote: »
    Nothing would support the broadcasts - even the "1080p50" Freeview STBs can't accept a 1080p50 broadcast signal.

    However, it would be trivial for new 1080p50 capable STBs to re-interlace the broadcasts to 1080i50 for legacy (!) TVs - just like current STBs down-convert HD to SD for SCART output.

    Cheers,
    David.

    The newer tv's can accept 50P via HDMI which opens the way for 50P broadcasting in theory (the problem still being a lack of tvs that can).

    However, it does open the way as you say for Set Top Boxes to receive 50P then reduce it to 50i or 25p for non compatible tv's. The only porblem here is whether or not existing boxes can be firmware upgraded to do it or whether or not it would take new boxes.

    If the latter, then it would mean having an upgrade date and obsoleting all existing boxes that couldn't beyond that date. A kind of digital switchover to 50P.
  • Nigel GoodwinNigel Goodwin Posts: 58,329
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    The newer tv's can accept 50P via HDMI which opens the way for 50P broadcasting in theory (the problem still being a lack of tvs that can).

    However, it does open the way as you say for Set Top Boxes to receive 50P then reduce it to 50i or 25p for non compatible tv's. The only porblem here is whether or not existing boxes can be firmware upgraded to do it or whether or not it would take new boxes.

    If the latter, then it would mean having an upgrade date and obsoleting all existing boxes that couldn't beyond that date. A kind of digital switchover to 50P.

    Where would the extra bandwidth come from?, Freeview already is too short on bandwidth with quality sacrificed to squeeze too many low quality channels in the space.

    But even more important, what would be the point?, the difference would be miniscule, and a FAR greater improvement would be to stick to 1080i50 and increase the bandwidth to a decent level. The original BBC HD channel on satellite was stunning, and was only crippled just before DTT HD started (presumably to make it look as bad as Freeview HD?).
  • White-KnightWhite-Knight Posts: 2,508
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    I never mentioned Freeview. There's plenty of space on Freesat with 1N coming online shortly.

    However, political will is another matter as you pointed out.
  • [Deleted User][Deleted User] Posts: 96
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    Where would the extra bandwidth come from?, Freeview already is too short on bandwidth with quality sacrificed to squeeze too many low quality channels in the space.

    But even more important, what would be the point?, the difference would be miniscule, and a FAR greater improvement would be to stick to 1080i50 and increase the bandwidth to a decent level. The original BBC HD channel on satellite was stunning, and was only crippled just before DTT HD started (presumably to make it look as bad as Freeview HD?).

    BBC & EBU studies show that actually 1080p50 needs less bandwidth than 1080i50, in some circumstances less than 1080p25 even! Certain types of motion blur are harder to encode than a sharp image apparently.

    BBC tried to get 1080p50 accepted as a requirement for Freeview HD when this was discovered but it was rejected as this was too far into the approvals process, great shame.

    If you have ever seen native 1080p50 compared to even excellent 1080i50 you wouldn't be claiming the difference to be miniscule. I'd take 6Mbps 1080p50 over uncompressed 1080i, yes I've seen a lot of uncompressed 1080i btw.
  • [Deleted User][Deleted User] Posts: 96
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    The only porblem here is whether or not existing boxes can be firmware upgraded to do it or whether or not it would take new boxes.

    If the latter, then it would mean having an upgrade date and obsoleting all existing boxes that couldn't beyond that date. A kind of digital switchover to 50P.

    The way to encode 1080p50 or p100, p300 even efficiently is to make the gop longer, so it covers the same time period regardless of frame rate. This means the decoder will need double the frame storage for p50 quadruple for p100, so not a chance of a firmware update fixing that.

    The higher the frame rate, the less difference there is between frames, less time for things to move. This is what makes the encoding more efficient, a nice side effect is that at very high rates eg p300 the main thing that changes between frames is sensor noise, as you reduce the bitrate the first thing that cannot be encoded is the sensor noise! Real noise reduction for free.
  • White-KnightWhite-Knight Posts: 2,508
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    You really sound like you know what you're talking about Captin. Nice to know someone else knows the virtues of 50P and above.
  • [Deleted User][Deleted User] Posts: 96
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    You really sound like you know what you're talking about Captin. Nice to know someone else knows the virtues of 50P and above.

    Just spent too long drooling over the 1080p50 &60 demos at the trade shows, never mind the p300 & p600 ones, wow now that is really amazing stuff. Not super slomo btw, real time ordinary stuff shot at 300 or 600 fps, it's like looking through a window.

    With the pace of adoption we have it will be another ten years before we see anything better than 1080i or 1080p25 in the home! At least there are no more interlaced formats being standardised, EBU refer to 1080i as legacy HD in all current papers and lectures.

    Oddly 3D seems to be the one hope for higher frame rates, the 3D effect is lost very quickly on camera pans at 24p. James Cameron is trying to convince studios that 3D needs to be made at 120p, modern cameras can shoot it and DCI digital cinema projectors can show it, so fingers crossed.
  • Nigel GoodwinNigel Goodwin Posts: 58,329
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    Captin wrote: »
    BBC & EBU studies show that actually 1080p50 needs less bandwidth than 1080i50, in some circumstances less than 1080p25 even! Certain types of motion blur are harder to encode than a sharp image apparently.

    Strange how no where in the world broadcasts it, BD with it's higher bandwidth doesn't do it, and all broadcasters have always said it's because the bandwidth requirements are much too high.

    BBC tried to get 1080p50 accepted as a requirement for Freeview HD when this was discovered but it was rejected as this was too far into the approvals process, great shame.

    Good job too :D it would be ludicrous to now introduce an entirely different and incompatible HD standard.

    If you have ever seen native 1080p50 compared to even excellent 1080i50 you wouldn't be claiming the difference to be miniscule. I'd take 6Mbps 1080p50 over uncompressed 1080i, yes I've seen a lot of uncompressed 1080i btw.

    Sorry, but I can't agree with you - massively overly compressed digital pictures are crap, and while I'll agree that 1080P50 has some advantages where bandwidth isn't a concern, it's just not going to happen.
  • 2Bdecided2Bdecided Posts: 4,416
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    Captin wrote: »
    Oddly 3D seems to be the one hope for higher frame rates
    I think it's having the opposite effect.

    What we have now are half-res broadcast 3D solutions (i.e. side by side), and full res 24p 3D on BluRay. The latter is really 48 full resolution HD frames per second.

    To do 3D at 50p means 100 frames per second - doubling the bandwidth again. If you talk to chip manufacturers, you find the main reason for supporting 60 progressive frames per second was to be able to handle full res 3D content, not actual content at 60fps. I know they can, and can deinterlace and output 60p, but it's not primarily why the capability is there (according to them - it surprised me).

    I don't know any silicon vendor that's talking about doubling up again to 120p (enabling 3D at 60p full res).

    James Cameron is trying to convince studios...
    James Cameron has said some things that I agree with, but surprisingly the industry doesn't choose to follow him. He wanted 48fps as standard the other year, yet everything is still 24fps. He's right about 24fps stutter being even more objectionable with 3D, but Hollywood is in no hurry to make all its films look like smooth high resolution video.

    Cheers,
    David.
  • 2Bdecided2Bdecided Posts: 4,416
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    However, it does open the way as you say for Set Top Boxes to receive 50P then reduce it to 50i or 25p for non compatible tv's. The only porblem here is whether or not existing boxes can be firmware upgraded to do it or whether or not it would take new boxes.
    Existing Freesat STBs are not designed to accept 1920x1080p50. I doubt the silicon in the older boxes (I think most of us have older boxes ;) ) is capable of decoding H.264 level 4.2. Most chips only go up to level 4.1 (60i max).

    http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC#Levels

    Cheers,
    David.
  • [Deleted User][Deleted User] Posts: 96
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    Strange how no where in the world broadcasts it, BD with it's higher bandwidth doesn't do it, and all broadcasters have always said it's because the bandwidth requirements are much too high.



    Good job too :D it would be ludicrous to now introduce an entirely different and incompatible HD standard.



    Sorry, but I can't agree with you - massively overly compressed digital pictures are crap, and while I'll agree that 1080P50 has some advantages where bandwidth isn't a concern, it's just not going to happen.

    When broadcasters say the bandwidth requirements are too high, they are talking about the requirements for 3Gigabit uncompressed HDSDI around the studios & playout centers. This is becoming less important as newer equipment is starting to interoperate with intermediate compressed video at 140 to 250Mb/s moving around instead. This is a fair way off being the norm though.

    Some encoder engineers used to think that 1080p50 needed more broadcast bandwidth than 1080i but recent studies have contradicted this. The EBU has been running a trade roadshow for several years to try to re-educate broadcast engineers.


    BTW 1080p50 isn't really a new incompatible standard, the standards are designed to be upwardly extendible, it's just a natural progression, it's only 1080p with a higher maximum framerate.

    Sport is mostly my area of experience and although most sports broadcasters think 1080i is great and "why would anyone want more?" oh dear! There are some in the industry who are frustrated that customer demand for 1080i (driven by the concept that 720p isn't real HD) has stifled 720p50&60 adoption, these are the people pushing for 1080p50&60.

    After all sport (ok not chess:) shot at 1080i just looks like SD sport with slightly sharper edges when everything stops moving for a moment! ;)

    Sport at 50&60p looks far more like being there, which is the point of sport on TV, isn't it?
  • [Deleted User][Deleted User] Posts: 96
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    2Bdecided wrote: »
    I think it's having the opposite effect.

    What we have now are half-res broadcast 3D solutions (i.e. side by side), and full res 24p 3D on BluRay. The latter is really 48 full resolution HD frames per second.

    To do 3D at 50p means 100 frames per second - doubling the bandwidth again. If you talk to chip manufacturers, you find the main reason for supporting 60 progressive frames per second was to be able to handle full res 3D content, not actual content at 60fps. I know they can, and can deinterlace and output 60p, but it's not primarily why the capability is there (according to them - it surprised me).

    I don't know any silicon vendor that's talking about doubling up again to 120p (enabling 3D at 60p full res).


    James Cameron has said some things that I agree with, but surprisingly the industry doesn't choose to follow him. He wanted 48fps as standard the other year, yet everything is still 24fps. He's right about 24fps stutter being even more objectionable with 3D, but Hollywood is in no hurry to make all its films look like smooth high resolution video.

    Cheers,
    David.

    Some are realising that 1080i side by side 3D is a bit crap and when the novelty of 3D on TV wears off viewers are noticing that it's very second rate. There are some in the industry who are trying to get ahead of this, once the infrastructure to handle 3D 1080p is there (usually 1080p25x2 or dual 1080i) often someone says "hey we can use this for 1080p50 one day too".

    Anything >50&60p is going to be a long way off for distribution but there is a great deal of interest in 300p cameras, they can make near perfect 50p & 60p for Euro & US markets simultaneously and also give great super slomo replays. There were several 300p cameras used at the Winter Olympics and some 600p models are planned to be used in the UK in 2012.


    Sadly the movie industry is heavily unionised and steeped in generations of technical lore, mostly about how to make 24p look like things are moving smoothly!! Will probably take several generations of James Camerons to change anything :(
  • White-KnightWhite-Knight Posts: 2,508
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    Sorry, but I can't agree with you - massively overly compressed digital pictures are crap, and while I'll agree that 1080P50 has some advantages where bandwidth isn't a concern, it's just not going to happen.

    I think you're missing the point here a little Nigel.

    The quicker you flash frames through the less noticible any artefacts are to the brain. So in actual fact you can get away with far more at 50fps than at 25fps. Also, 50fps is far sharper and clearer than 25fps even with heavier compression.

    Now I'm not personally saying that higher compression should be used. I'd rather see compression at the same levels or even reduced with 50P than compared to 25P.

    Where 50P and above really comes to the fore is in movement as Captin said. The higher the frame rate, the less motion blur you see because the less a subject moves in any given frame. A sharper frame image = a better final quality of picture which is why 50P can be far superior even with higher compression because compression aside the whole frame is of better quality.

    eg. If you're shooting 25 frames per second then each frame is 4 hundredths of a second long then you have 4 hundredths of a seconds worth of blur in each frame (actually less because I'm ignoring the times between frames taken to open and close the shutter in this example for simplicity but that said as it also applies to the faster frame rate the difference is still there).

    If you shoot the same scene at 50 frames per second, then in each frame you only have 2 hundredths of a second of movement. Instanly therefore you've halved the blur in the frame . The effect of that on sharpness is far superior to any small reduction in compression artefacts.

    Thus it produces a far sharper, clearer and more life like picture.

    For sports the advantage is:

    1. You get much reduced motion blur, in fact you halve it with every doubling of frame rate

    2. You can run faster shutter speeds without suffering frame jumping or jerkiness cause by the unrecorded portion of the action between frames becoming apparent.


    I found this example on the internet, not sure its the best example out there as the initial shutter speed is quite high anyway, but:

    http://s4.hubimg.com/u/2974343_f520.jpg

    On the left is 1/350th second. On the right is 1/180th second.

    The picture on the left captured with twice the shutter speed is sharper and clearer and so far as the bat is concerned which is the point of most movement, the difference is like night and day.

    Remember a video picture is only 25 stills strung together (or 50 in the case of 50P) so ultimately quality is linked to the qaulity of each individual frame which is why compression affects picture quality and why increasing individual frame quality increase picture quality.
  • [Deleted User][Deleted User] Posts: 96
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    I think you're missing the point here a little Nigel.

    The quicker you flash frames through the less noticible any artefacts are to the brain. So in actual fact you can get away with far more at 50fps than at 25fps.

    Good explanation, do I know you? I think you have been to the same demos, lectures and conferences as me :)

    There is also a factor in that interlaced video, especially 4:2:0 as is usually broadcast really gets in the way of video compression. For the same visual compression level a progressive source uses less bits, it's easier for the encoder to break down.

    While it's true that there is no difference between 1080p25 and that same video delivered as 1080i when compression is very low e.g bluray or a 50Mbps studio feed. In any real world hdtv broadcast situation 1080p25 will use look better than it's 1080i equivalent.

    Why would BBC HD be using it if there was no benefit?
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