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  1. I understand the following:

    PAL - 576 x 720 (interlaced)
    NTSC - 480 x 720 (interaced)

    but the PAL broadcast is a 4:3 (non-wide) resolution???

    is there a different res for 16:9 (widescreen) broadcasts which most channels are nowadays?

    what is that resolution?

    thanks
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  2. 1920x1080 or 1280x720.
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  3. First, with MPEG encoding any frame size can be displayed with 4:3 or 16:9 aspect ratio. So a 720x576 (5:4) frame can encode either a 4:3 or 16:9 video.

    https://forum.videohelp.com/topic365439.html#1948988

    Digital broadcasts are not restricted to DVD frame sizes. You will often find digital PAL SD at around 532x576. I know Doctor Who was broadcast as 720x576 16:9 DAR.
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  4. Member ntscuser's Avatar
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    Originally Posted by snadge
    I understand the following:

    PAL - 576 x 720 (interlaced)
    NTSC - 480 x 720 (interaced)

    but the PAL broadcast is a 4:3 (non-wide) resolution???

    is there a different res for 16:9 (widescreen) broadcasts which most channels are nowadays?
    No, it's still 720x576
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  5. Member edDV's Avatar
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    Originally Posted by snadge
    I understand the following:

    PAL - 576 x 720 (interlaced)
    NTSC - 480 x 720 (interaced)

    but the PAL broadcast is a 4:3 (non-wide) resolution???

    is there a different res for 16:9 (widescreen) broadcasts which most channels are nowadays?

    what is that resolution?

    thanks

    Both PAL broadcasts* are 720x576. The only difference between 4:3 or and wide flagged 16:9 is the mapping of the non-square pixels to a display monitor. Assuming a monitor (e.g. computer monitor) with square pixels and no vertical upscale, 4:3 would be mapped to 768x576, 16:9 would be mapped to 1024x576.

    LCD/plasma TV sets usually scale both h and v to native display resolution. Typical native resolutions on modern flat screen 16:9 sets are 1024x768 (wide pixels), 1366x768 (square pixels), and 1920x1080 (square pixels). So if you think this through, both transmission and display can have non-square pixel aspect ratios.

    4:3 digital TV sets usually display 4:3 full screen and 16:9 as letterbox.


    *proprietary broadcasts such as satellite dbs can use arbitrary transmission resolutions but these are scaled to 720x576 SD output at the set top box. Upscaled HD 1280x720p and 1920x1080i outputs may also be provided.
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  6. thanks...

    ...so basically 16:9 is filmed in narrow so when its broadcast as 720x576 your widescreen TV maps it to 1024x576 (stretches the pixels and cos it was filmed narrow its all in proportion on 16:9 screen) and if you have LCD it then UPSCALES that image to say 768x1366 / 1080x1920....


    i get it now....

    get my SK+HD installed today - cant wait
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  7. Always Watching guns1inger's Avatar
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    Originally Posted by snadge
    thanks...

    ...so basically 16:9 is filmed in narrow so when its broadcast as 720x576 your widescreen TV maps it to 1024x576 (stretches the pixels) and if you have LCD/Plasma it then UPSCALES that image to say 768x1366....


    i get it now....
    SD digital broadcast is like that.

    HD varies.

    In Australia we have one broadcaster broadcasting in (720 x )576p, another in 720p, and three in 1080p
    Read my blog here.
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  8. im getting SKY+HD installed today with about 20 HD channels - is there anyway of finding out what those HD channels are broadcast in?

    e.g. BBC-HD is broadcast in 1080i

    i was under the impression there are no sat broadcasts in 1080p because not enough bandwidth to do so??
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  9. I don't know about SKY+HD but my cable box has little indicator lights that say 1080i, 720p, or 480i. If the SKY+HD box has a passthrough mode (the video is sent to the TV in the same format it is received) your TV might be able to tell you. My Samsung HDTV shows the source format when I press the Display button. Of course, that last option tells you the format that is being sent from the cable/sat box to the HDTV. The sat box may convert broadcast 1440x1080i to 1920x1080i before sending it to the HDTV.
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  10. yeah, the SKY box outputs at either 720p or 1080i - you choose - what I want to know is what the channels broadcast in.... - if say one is 720p then its been further upscaled by the SKY+HD box to 1080i then my TV is rescaling that to 768p

    its been installed today and HEY IM IMPRESSED...
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  11. Member ntscuser's Avatar
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    Originally Posted by snadge
    yeah, the SKY box outputs at either 720p or 1080i - you choose - what I want to know is what the channels broadcast in.... - if say one is 720p then its been further upscaled by the SKY+HD box to 1080i then my TV is rescaling that to 768p
    Regardless of HD source you should set the output of the box to whichever is closest to the "native resolution" of your LCD which in this case would be 720p.
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  12. i have tried both and I have to say 1080i honestly look slightly sharper than 720p

    my set is a crappy BUSH 32" LCD HD ready , the upscaler is severely poor hence when it upscales 720p to 768p it loses quality quite a bit , 1080i however doesnt get upscaling artifacts as it is downscaled...

    i need to do further testing - its just been installed 30mins ago...

    VERY IMPRESSIVE

    Ive noticed that cos theres much more detail it makes the TV feel BIGGER hehe
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  13. Just play with both output options and decide which you think looks better.
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  14. i have tried both and I have to say 1080i honestly look slightly sharper than 720p

    my set is a crappy BUSH 32" LCD HD ready , the upscaler is severely poor hence when it upscales 720p to 768p it loses quality quite a bit , 1080i however doesnt get upscaling artifacts as it is downscaled...

    i need to do further testing - its just been installed 30mins ago...

    VERY IMPRESSIVE

    Ive noticed that cos theres much more detail it makes the TV feel BIGGER hehe
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  15. Member edDV's Avatar
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    Without knowing exactly how Sky does it, the source resolution, transmission resolution and set top box output resolution are three different things. Conversion is happening all along the chain. It seems universal that where 720p, 576p and 480p are used, frame rate is 50Hz (59.94 in NTSC markets) to facilitate easy conversion to interlace. But more important for overall picture quality is bit rate and the compression codec being used.

    At the receiver end for some reason that I still don't understand, HD set top boxes only output 1920x1080i or 1280x720p forcing all HDTV sets to rescale once again to about 3-5% more than native resolution for overscan. You would think set top boxes would scale for popular display resolutions like ~1400x787 (overscanned 1366x768) in order to avoid that last rescale. Alas, that isn't the way it works so one must experiment to see which output resolution works best for that particular HDTV. In PAL markets at least film based material is sent pseudo progressive for interlace so you only have to deal with scaler artifacts. In NTSC markets, the HDTV must handle inverse telecine as well for interlace outputs. Quality of inverse telecine varies by class of HDTV processor.
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  16. Live sporting events that are broadcast as 720p may look better sent to the TV as 720p. Otherwise the 720p50 will be converted to 1080i25 (each field from one 270p50 frame) by the satellite receiver and the TV will have to deinterlace back to 768p50. This may lead to artifacts. The thin white lines on a soccer field may appear jagged, as double lines, etc. when the camera pans.
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  17. thanks for the info guys - much appreciated

    loving the SKY+HD - its just made me realise just how poor my TV is... the upscaling is probably better than my DVP5980 - BBC1 is almost true HD its that good upscaling...

    BBC-HD
    NATGEO HD
    DISCOVERY HD
    EUROSPORT HD
    CH4 HD
    SK1 HD
    MTV HD
    + more

    all brill - mind i have noticed some are better than others... probs depend on the program broadcast but so far SKY 1 HD , MTV HD and CH 4 HD dont seem as 'sharp' as the others....
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  18. In our area the HD stations often show upscaled SD. Maybe that's why some of the stations aren't as sharp? HD material is most likely to be shown in prime time.
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  19. yeah on SKY it has HD in the EPG - if its NOT there on a HD channel then it MUST be upscaled (which ive seen) - mind some are pretty good upscaling

    didnt know about SKY ANYTIME until i started playing with it

    it downloads random movies , docs , news , sport etc to the SKY+HD box and you can go into it and start watching them on the fly (also whilst recording other channels at same time) - BRILLIANT

    takes a few days to build up like so i dunno how exactly it works , they must download when in standby or summit

    its true - once youve had HD you wont go back

    Im thinking of activating the movies channels (9 HD movie channels) for 9 month
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    Originally Posted by edDV View Post
    Both PAL broadcasts* are 720x576. The only difference between 4:3 or and wide flagged 16:9 is the mapping of the non-square pixels to a display monitor. Assuming a monitor (e.g. computer monitor) with square pixels and no vertical upscale, 4:3 would be mapped to 768x576, 16:9 would be mapped to 1024x576. .
    So how do I tell anything like Media Player Classic or Youtube to regard the pixels as non-square? If I convert a 16:9 file using e.g. WinAVI, then I get black bars above and below. By choosing 720x404 I get the right frame.
    Martin
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