HDTV Resolution

Archived from groups: alt.tv.tech.hdtv (More info?)

"Marty C" <mccohen@optonline.net> wrote in message
news:H2kCd.6511$ch1.2281@fe12.lga...
>I am a newbie to this stuff. Can somebody explain resolution and pixels as
>it relates to HDTV? What I understand is that true HDTV broadcasts in over
>2 million pixels, but today's HDTV's can not display that many pixels. I
>am looking at DLP, and most DLP TV's only do 1280x720, which is not even 1
>million pixels. Is this correct? A good explanation would really help me
>out. Thanks.


The requirement for a signal to be considered HD is that it have either 720
progressively-scanned lines or 1080 interlaced lines. Thus either the 720p
or 1080i format qualifies. While the general intent has been for pixels to
be square, and hence that 720p would be 1280x720 and 1080i would be
1920x1080, in practice there is no minimum requirement for a particular
horizontal resolution, and 1080i in particular is probably limited to around
1440 most of the time (due to either the camera or other source,
compresion/transmission setting and limitations, or limitations of the
display). Also, when you consider losses of effective or perceived vertical
resolution due to interlace, 1080i probably averages around 1440x750 or so.
Thus either 1080i or 720p only hover around one megapixel equivalent
resolution.

When it comes to displays, generally anything capable of displaying at least
720 lines progressively qualifies as HD. So 720p displays are considered HD
even if they're showing an interlaced (1080i) signal. 1024x1024 displays are
controversial, but I consider them HD even though their horizontal
resolution is insufficient for the full theoretical width of the HD formats
(it only misses the typical 1280-1440 range by a little, so I personally
think this is close enough that most people would never notice the
difference). What it all boils down to is that "HD" signals and displays are
dramatically superior to the 4:3 480i formats we're used to watching (about
4-5x the overall resolution), and generally have about 1 megapixel of
resolution or more.

Archived from groups: alt.tv.tech.hdtv (More info?)

To add to Matthew's excellent response.

The CE industry has tossed around the loosely defined terms "DTV-ready" and
"HDTV-ready", and often all those terms mean is that the display/DTV can
`tune-in or accept as input all 18 of the ATSC formats', and not necessarily
that the display/DTV can also `display more than 720 progressive or 1080
interlaced lines'.

See:

http://www.ce.org/shared_files/res [...] itions.pdf


(http://www.ce.org/about_cea/cea_initiatives/viewCEAInitiativesResources.asp
?name=269#Charts)

For CEA's attempt to standardize how the CE industry should label products.

Thomas Gilg

Archived from groups: alt.tv.tech.hdtv (More info?)

"William Oertell" <oertell_NOT@pacbell.net> wrote in message
news:10tpi047lleo42d@news.supernews.com...
> >Yes, and I read some time ago that broadcast 480i was some what less,
> >~350?
>>Could be wrong, but maybe that's why DVDs look so much better on a 480i
>>tv, could be the first time most people really have seen a full 480i.
>
> Broadcast TV consists of 525 lines, but the vertical blanking interval
> takes
> up something like 25 lines.
>
>
An interlaced system gives a vertical resolution of about 70% of the number
of active scan lines,
so yes standard US TV has about 350 lines of vertical resolution. The
resolution of 480P
(progressive scan) gives the full 480 lines of vertical resolution, about a
40% increase.

Broadcast TV has a horizonal resolution limit of about 330 lines, but
component video allows the
full DVD resolution of 540 lines (720 pixels/1.333)