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When is 720p Not 720p?
Henning Hoffmann writes "HDBlog has an interesting entry about many home theater displays.
Home theater displays around the resolution of 720p (most DLP, LCD, and LCOS displays) must convert 1080i material to their native resolution for display. No surprise there. But many displays do this by discarding half of the 1080i HD signal, effectively giving 720p viewers an SD signal - not watching HD at all! "
Home theater displays around the resolution of 720p (most DLP, LCD, and LCOS displays) must convert 1080i material to their native resolution for display. No surprise there. But many displays do this by discarding half of the 1080i HD signal, effectively giving 720p viewers an SD signal - not watching HD at all! "
This sounds like the visual version of what Creative Labs has been doing for YEARS with their Sound Blaster audio cards. With most other cards if you want to record with a sample rate of 44.1 khz, you record at 44.1 khz, but even with the newer Sound Blaster cards it must be resampled to 48 khz first.
It doesn't matter if you are sampling up or down, resampling is bad, your best b
et is to find a device without it, or if it is necessary like in this case, the one that does the best conversions.
If I bought one of these displays I would be pretty pissed, but I doubt there is much that can be done about it, if you COULD do something than companies like Creative Labs would be out of business.
There's got to be a fairly straightforward formula relating inherent resolution loss when performing any noninteger upsampling, or any downsampling. Any other change in resolution must necessarily degrade the signal, yes? (Except perhaps if a clever algorithm could losslessly encode the original data in a 1.5x-upsampled version, without distorting it.)
Paleotechnologist and connoisseur of pretty shiny things.
When the un-washed masses can't actually tell the difference (they can't even see DCT blocking) and you can get away with selling this crap to them..
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When I upgrade to an HD idiot box, I plan on sticking with tried-and-true CRT. IMHO, you can't beat the picture quality/price, and I have yet to hear a compelling reason to fork out thousands of dollars for the trendier offerings.
"Ask not what your country can do for you." --John F. Kennedy
If the broadcast is 1080i, and your display isn't 1080i, I don't think it's logical to assume the quality of the downsampled video will be equivalent to a true 720p broadcast.
When I get around to buying a HD television (not any time soon, I do all my televisioning on my computer), it will be a true 1080i (are there 1080p televisions?) display so I'll know I'm getting the full potential of HD.
Unless I'm strapped for cash, of course, in which case I'll just suck it up and know my 720p won't be the best thing for watching 1080i content on.
On the plus side, it's important to get the facts out there for the consumer, who will likely (although not logically) assume he's/she's getting more than they really are.
Why not submit a link to the original article, rather than a link to your blog, which consists only of a link to the original article?
Otherwise, people might assume this is a shameless attempt to draw traffic to your site.
But this is true for SD display on a double-scan TV as well.
The "digital feature box" in the TV is supposed to combine the two fields into one single frame. This is usually referred to as "motion compensation" or some other nifty marketing term.
This is what separates the cheap from the expensive TVs.
There has been a similar issue for years with audio amplifier specs.
Mfgrs usually tout their amps with having "200 watts of pulsing music power" which usually means 100 watts per channel peak. In reality it's more like 70.7 watts/channel RMS (assuming they're not still lying).
Don't anthropomorphize computers, they don't like it.
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Kind of hard to "do your research" when you can't find out how the conversion takes place or can't understand how it all works. This is not a consumers fault kind of thing. This kind of information is not made known unless people ask the question. Who would have thought to ask a question like this?
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Yes. Go to a showroom and look at the displays. If you see some that have greater vertical resolution than the non-HD models, there you go. If you can't see a difference, then it doesn't make a difference.
That's not necessarily good advice. At the showroom, everything you see is optimized for selling the display. You might not notice any problems until you start to view content outside of their controlled environment.
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My DLP monitor's native resolution is 720p. Before purchasing the unit, I read up about signal, conversion, interlacing, etc. The conclusion I reached is that my monitor should do one thing and do it well. That one thing is to display a picture at its native resolution.
Almost everything I've read notes that the deinterlacing hardware in most TV's flat out sucks. My solution? I bought a Samsung DLP sans ATSC tuner. My TV is a display, nothing more. Had I been able to, I would have purchased it without the NTSC tuner as well. Buying the tuner separately affords me the opportunity to buy a better quality piece of hardware without the redundancy of having purchased the same hardware in my monitor.
I'll deliver a quality 720p signal to my monitor, and it will display the picture. What's more to ask?