Archived from groups: alt.tv.tech.hdtv (
More info?)
Alan Figgatt wrote:
> L Alpert wrote:
>> Hasenpfeffer wrote:
>>
>>> Here's my understanding of the situation:
>>>
>>> 480i with a bandwidth of 6 MHz is SDTV. Also called NTSC here in
>>> North America.
>>> 720p and 1080i is HDTV. There may be other formats, like 1080p,
>>> considered to be HDTV but rarely used.
>>> 480p is EDTV (since it's neither SDTV nor HDTV, and can have a
>>> higher bandwidth than SDTV, e.g. downsampled HDTV)
>>>
>>> I hope it's enough language to communicate.
>>
>>
>> Actually, from what I understand (and I could be wrong), the 480p is
>> done internal to the unit, similar to a DVD player, so the bandwidth
>> would be the same as the input is still 480i (unless, of course,
>> these units can accept an input of 720p or 180i and downscale it to
>> 480p). Though I can't see the sense of setting up for HD service to
>> downscale.....
>
> You are thinking about the 480p progressive scan feature for DVDs
> which can deinterlaced film source material into 720x480p. This
> feature is also known as 3:2 pull down. This is not the same as 480p
> widescreen source broadcasts as one of the ATSC standards, which Fox
> used to do until they switched to 720p this year.
How many stations are going to broadcast the 480p version of DTV, and how
many cable and satellite carriers will offer this scale of service?
>
> There are 18 different formats accepted for ATSC many of which are
> not HD. See
http/www.hdtvprimer.com/ISSUES/what_is_ATSC.html for
> the list. Enhanced Definition for OTA broadcasts effectively means
> the 704x480p 16:9 standard, but with Fox dropping it, I don't know if
> there are any stations broadcasting at that standard in the US any
> more. All of the major networks are either 720p60 or 1080i60 now.
Well, I wasn't sure if the EDTV was expecting the source to be 480p or if
was scaling it similar to PS DVD players.
>
> For TV sets, ED has come to mean 16:9 480p sets. Fixed pixel ED
> plasmas have a resolution of 852x480p pixels. At 852 horizontal
> pixels, these sets do have higher resolution than the 720 or 704
> pixels of resolution for US encoded DVDs or ED broadcasts. They
> upscale DVDs horizontally & downscale the 720p or 1080i signals to
> 480p and still provide a pretty good picture for medium sized 37" or
> 42" screens at typical 8 or 10 feet viewing distance.
I would still have a problem with going through the trouble of obtaining a
720p or 1080i source signal and downscale it.
>
> Alan F