• US TV Resolution

    From JMB99@21:1/5 to All on Tue May 28 08:21:26 2024
    A friend from US has just been visiting me.

    When he got home, he made this comment.



    "We’re back home and (his wife) commented on the clarity of the UK soap
    that she has been watching. To me, it looks as if they are recording at
    a greater quality than 4K. Everything is in focus from near to far and
    it almost seems to be 3D.

    I remember the BBC recording things for future receivers.

    We noticed something similar when watching the film at the Sphere, which
    is 18K."




    Any suggestions?

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  • From John Williamson@21:1/5 to All on Tue May 28 09:18:43 2024
    On 28/05/2024 08:21, JMB99 wrote:
    A friend from US has just been visiting me.

    When he got home, he made this comment.



    "We’re back home and (his wife) commented on the clarity of the UK soap that she has been watching. To me, it looks as if they are recording at
    a greater quality than 4K. Everything is in focus from near to far and
    it almost seems to be 3D.

    That may be due to lighting and optical choices. Contrast (AKA gamma)
    also has an effect on perceived "solidity" of an image. Edge enhancement
    can also be applied when compressing the data for broadcast. You also
    need to check that both receivers are set up in the same way. This is a
    lot easier than it used to be...

    If you have a video camera that can connect to your computer, you can
    simulate all these effects using even a basic program such as Microsoft
    Movie Maker or whatever they call it nowadays. It can also be done using
    still pictures using your favourite image editor.

    More light when shooting gives better depth of field as the aperture can
    be smaller, though with modern sensors, you can also play off aperture
    against sensor gain, which has an effect on noise, which changes noise affecting perceived sharpness as well as changing the required bandwidth
    for digital compression.

    The same used to apply when using film. More sensitive film (Or slow
    film which had been push processed, common on news footage) had bigger
    grain.

    I remember the BBC recording things for future receivers.

    They have always worked to the best available standards. They currently
    specify a higher source bit rate for digital programming than some other programme distributors. This reduces digital artifacts and allows better quality upscaling.


    We noticed something similar when watching the film at the Sphere, which
    is 18K."

    The published spec for the Sphere is 16,000 pixels by 16,000 pixels,
    which works out at 1,600 pixels per square foot ( About 3 pixels per
    inch) on the screen. These figures are meaningless when comparing it
    with other formats, as you are viewing the Sphere images from much
    further away than almost all other formats. If you are watching a 2.35:1
    ratio movie (Cinema standardish), then vertical resolution is unlikely
    to be more than 6.6 k on the Sphere screen anyway. Most films now are
    usually shot at 4K (UHD), and are still being transferred to film for
    some markets. 8K is becoming more common.

    The Sphere uses minimal digital compression between shooting and
    projection, unlike all broadcast formats and most cinemas, and much of
    the material is digitally generated anyway.

    Any suggestions?


    --
    Tciao for Now!

    John.

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  • From Andy Burns@21:1/5 to John Williamson on Tue May 28 09:46:18 2024
    John Williamson wrote:

    The published spec for the Sphere is 16,000 pixels by 16,000 pixels

    Does it show different images inside and outside?

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  • From Mark Carver@21:1/5 to John Williamson on Tue May 28 14:25:43 2024
    On 28/05/2024 09:18, John Williamson wrote:


    I remember the BBC recording things for future receivers.

    They have always worked to the best available standards. They currently specify a higher source bit rate for digital programming than some other programme distributors.

    I don't think they do, they use the DPP spec, that is used by all UK broadcasters ?

    <https://www.dropbox.com/s/sjsjlf4qtm68xc3/TechnicalDeliveryStandardsBBCFile.pdf?e=1&dl=0>

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  • From John Williamson@21:1/5 to Mark Carver on Tue May 28 16:33:48 2024
    On 28/05/2024 14:25, Mark Carver wrote:
    On 28/05/2024 09:18, John Williamson wrote:


    I remember the BBC recording things for future receivers.

    They have always worked to the best available standards. They
    currently specify a higher source bit rate for digital programming
    than some other programme distributors.

    I don't think they do, they use the DPP spec, that is used by all UK broadcasters ?

    <https://www.dropbox.com/s/sjsjlf4qtm68xc3/TechnicalDeliveryStandardsBBCFile.pdf?e=1&dl=0>


    I slouch corrected. The major players all appear to have harmonised
    since I last wanted know what I needed to submit. Mind you, there seems
    to be a lot of stuff on Freeview that doesn't meet that spec.

    --
    Tciao for Now!

    John.

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  • From Brian Gregory@21:1/5 to Mark Carver on Tue May 28 22:20:05 2024
    On 28/05/2024 14:25, Mark Carver wrote:
    On 28/05/2024 09:18, John Williamson wrote:


    I remember the BBC recording things for future receivers.

    They have always worked to the best available standards. They
    currently specify a higher source bit rate for digital programming
    than some other programme distributors.

    I don't think they do, they use the DPP spec, that is used by all UK broadcasters ?

    <https://www.dropbox.com/s/sjsjlf4qtm68xc3/TechnicalDeliveryStandardsBBCFile.pdf?e=1&dl=0>


    My PVR recordings from satellite show BBC bitrate are quite good for SD compared to other TV stations but not particularly high for HD. I seem
    to remember Channel 4 HD has the best HD bitrate of all.

    It can be difficult to compare though, for instance how can you compare
    a fixed bitrate channel and a variable bitrate one to judge which is best?

    For Freeview it'll be different because it's far more expensive to have
    high bitrates on Freeview.

    I'd guess all the Freeview HD channels will be sharing a single
    statistical variable bitrate encoder with no particular channel or
    channels given any overall advantage or disadvantage.

    --
    Brian Gregory (in England).

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  • From Mark Carver@21:1/5 to Brian Gregory on Wed May 29 11:06:51 2024
    On 28/05/2024 22:20, Brian Gregory wrote:
    On 28/05/2024 14:25, Mark Carver wrote:
    On 28/05/2024 09:18, John Williamson wrote:


    I remember the BBC recording things for future receivers.

    They have always worked to the best available standards. They
    currently specify a higher source bit rate for digital programming
    than some other programme distributors.

    I don't think they do, they use the DPP spec, that is used by all UK
    broadcasters ?

    <https://www.dropbox.com/s/sjsjlf4qtm68xc3/TechnicalDeliveryStandardsBBCFile.pdf?e=1&dl=0>


    My PVR recordings from satellite show BBC bitrate are quite good for SD compared to other TV stations but not particularly high for HD. I seem
    to remember Channel 4 HD has the best HD bitrate of all.

    The DPP document I quoted is concerned with acquisition, studio
    production, and playout centre standards, the emission parameters for
    code/mux are the wild west, and is more within Ofcom's domain.

    It can be difficult to compare though, for instance how can you compare
    a fixed bitrate channel and a variable bitrate one to judge which is best?

    For Freeview it'll be different because it's far more expensive to have
    high bitrates on Freeview.

    Yes, although an expensive modern encoder will make a better job than a
    15 year old one, everything else being equal, so you can't judge of bit
    rates alone (if at all)

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