zululami
Banned
Please help me guys... Is it worth it to buy an HD PVR decoder if you have a TV marked as 'HD READY'? I plan to buy full HD in three months... But are there any short term benefits to buying this decoder now? Thank you...
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HD ready and Full HD
- Thread starter zululami
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PostmanPot
Honorary Master
Yes. Most/all HD Ready TVs are 720p (720 vertical lines), and HD PVR is max 720p. Full HD = 1080p.
LCBXX
Honorary Master
Yes
HD ready normally refers to a 720p resolution TV.
The HD PVR is actually only a "HD ready" PVR since the broadcast is 720p.
So if you can't wait, the two will complement each other.
However, if you add a Blu-ray or other 1080i/p sources (PS3 etc.) you will be limited.
The HD PVR is actually only a "HD ready" PVR since the broadcast is 720p.
So if you can't wait, the two will complement each other.
However, if you add a Blu-ray or other 1080i/p sources (PS3 etc.) you will be limited.
JerryMungo
Honorary Master
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And what is a 'normal' (old school) TV?
Up to 720x576 (PAL), usually quite a bit less.
greg_SA
Expert Member
And "old school" TV is also interlaced, so you old get half a frame at a time.
Wow didn't know that - always tort it runs @ 1080p.
So when connected to a full HD tv, does it run on 1080p ?
Or only when u watching a full hd channel like SS3HD ?
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Quantum Theory
Executive Member
You're not watching a Full HD channel, just HD. HD broadcasting standard around the is 720p or 1080i, not 1080p
The HD DSTV channels are broadcast in 720p. Thus, picture quality is limited by this, to a certain extent.
Assuming the 720p signal received by your decoder is true 720p (often, it's highly compressed, and nowhere near the quality it COULD be), the signal is either displayed at 720p (untouched), or upscaled to 1080p (if you have a TV that supports 1080p) by the decoder and/or TV.
Unfortunately, there's not way to turn 720p into 1080p without losing some quality; the information that you're "displaying" was not in the original signal. Interpolation algorithms "stretch" the 720p signal to 1080p. Fortunately, interpolation methods other than simple pixel replication (which would yield perceptually poor results) are generally used. While the entropy of the signal is modified, good interpolation algorithms tend to yield perceptually better picture quality.
So yes, you will "see" 1080p on the screen, but it is derived from a 720p (or worse) source, and thus the perceived picture quality will not be as good as when viewing content from a true 1080p source.
zululami
Banned
Thank you all for your sound advice... I am definitely gonna buy this decoder...
PostmanPot
Honorary Master
Is it still on special for ±R1,400?
isie
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yep
genetic
Honorary Master
HD PVR also broadcasts in 1080i full HD - not only 720p
genetic
Honorary Master
Supersport broadcasts in 1080i - full HD, however it's an interlaced transmission rather than progressive.
Smurfatefrog
Expert Member
Supersport is 720p (better for fast moving pictures), while I think Discovery is 1080i
1080i is generally not referred to as Full HD
genetic
Honorary Master
Full HD is a marketing ploy which refers to 1080p as you say. Both 1080i/p have a temporal resolution of 1920x1080, however the progressive image has many advantages over it's interlaced counterpart.
SuperSport only broadcasts in 576i and 1080i - not 720p.
http://www.facebook.com/group.php?gid=281551516057
http://en.wikipedia.org/wiki/SuperSport_(TV_channel)
Roman4604
Executive Member
I thought the same, but after plenty of flicking back & forth between 720p & 1080i on the HDPVR during various (types of) sports broadcasts, I cant see a discernable difference in motion distortion/lag between the two.
Maybe its due to the competency of my Samsung 50Hz LCD's de-interlacing/motion compensation circuitry or possibly due to most sport content being recored in 1080i at source (HD camera).
I do however notice a slight improvement in picture crispness at 1080i, probably due to the input signal exactly matching the native res of the TV (i.e. it doesnt perform any pixel alteration/interpolation).
Thats not entirely correct.
Manufacturers will specify a device is HD capable if it can natively output or display an image of (at least) 1280x720 pixels (e.g. DSTV HDPVR, games consoles, TVs etc.). For TVs/displays this means the panel actually has a minimum of 1280 pixels horizontally (across) and 720 vertically (down).
The HD Ready label is specified for devices that can accept an input signal of at least 1280x720 but physically do not have 1280 pixels horizontally (and/or 720 vertically).
This means HD Ready display devices need to downscale the original image to their lesser native resolution (usually 1024 horizontally). This downscaling will result in some level of alteration/degredation of the original image as each individual pixel must display a composite of 2/3 of the original pixels.
How competently this is performed depends on the proficiency of the downscaling circuitry in the HD Ready TV/display.
Quantum Theory
Executive Member
Not true. With 1080i two consecutive frames are carried in the 1920 x 1080 resolution (normally at about half the frame rate of a progressive image). Each alternate line belongs to a different frame. When the image is static these 2 consecutive frames are used to build a full 1080p image. As soon as that image starts moving, this can't be done and the resolution drops to 1920 x 540, because line doubling is used during de-interlacing. Saying that both 1080i/p is the same resolution is completely wrong. Had this whole argument with another guy in another thread recently.
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