i and p

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

What is the "i" and "p" in 480i, 720p, etc.? Not only what does it stand
for, but technically speaking as well.

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

TV scanning started as progressive scan. The complete picture at a fixed
scan rate, be it 24 per sec or 60 or whatever. But there was not enough
bandwidth. So a basic way to compress the information to fit into 1/2 the
bandwidth is to scan only 1/2 the picture (in alternative lines) per scan
rate per sec.

This achieved the objective, and until large screen sizes became common,
flicker was not an issue.

Today 1080i may have more resolution in a still picture than a 720p setup,
but with moving objects the progressive approach works better and actually
provides more apparent resolution. The best display setup would be 1080p24
for film and 1080p60 for live action video, but current transmission
bandwidth does not accomodate 1080p60. It is possible to convert a 1080i60
transmission into a 1080p60 display but that does not actually increase the
actual resolution available.

Richard.

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

"Eddie G" <mickeddie at comcast.net> wrote in
newsuKdnWfhFMCQUhfcRVn-vA@comcast.com:

>
> "Richard" <rfeirste at nycap.rr.com> wrote in message
> news:10ol9tci73r3c93@corp.supernews.com...
>> TV scanning started as progressive scan. The complete picture at a
>> fixed scan rate, be it 24 per sec or 60 or whatever. But there was
>> not enough bandwidth. So a basic way to compress the information to
>> fit into 1/2 the bandwidth is to scan only 1/2 the picture (in
>> alternative lines) per scan rate per sec.
>>
>> This achieved the objective, and until large screen sizes became
>> common, flicker was not an issue.
>>
>> Today 1080i may have more resolution in a still picture than a 720p
>> setup, but with moving objects the progressive approach works better
>> and actually provides more apparent resolution. The best display
>> setup would be 1080p24 for film and 1080p60 for live action video,
>> but current transmission bandwidth does not accomodate 1080p60. It is
>> possible to convert a 1080i60 transmission into a 1080p60 display but
>> that does not actually increase the actual resolution available.
>
> You say progressive works better for moving objects. Does this mean I
> should set my cable box to 720p instead of 1080i? Also, when 1080p
> becomes available, will we all need new t.v.'so, or will it be in the
> converter (for those of us that do not have hd integrated in the set)?
>
> Eddie
>
>
>

Sharps new 45" LCD converts to 1080p

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

"Eddie G" <mickeddie at comcast.net> wrote in message
newsuKdnWfhFMCQUhfcRVn-vA@comcast.com...
>
> "Richard" <rfeirste at nycap.rr.com> wrote in message
> news:10ol9tci73r3c93@corp.supernews.com...
>> TV scanning started as progressive scan. The complete picture at a fixed
>> scan rate, be it 24 per sec or 60 or whatever. But there was not enough
>> bandwidth. So a basic way to compress the information to fit into 1/2 the
>> bandwidth is to scan only 1/2 the picture (in alternative lines) per scan
>> rate per sec.
>>
>> This achieved the objective, and until large screen sizes became common,
>> flicker was not an issue.
>>
>> Today 1080i may have more resolution in a still picture than a 720p
>> setup, but with moving objects the progressive approach works better and
>> actually provides more apparent resolution. The best display setup would
>> be 1080p24 for film and 1080p60 for live action video, but current
>> transmission bandwidth does not accomodate 1080p60. It is possible to
>> convert a 1080i60 transmission into a 1080p60 display but that does not
>> actually increase the actual resolution available.
>
> You say progressive works better for moving objects. Does this mean I
> should set my cable box to 720p instead of 1080i? Also, when 1080p
> becomes available, will we all need new t.v.'so, or will it be in the
> converter (for those of us that do not have hd integrated in the set)?

TV's are only capable of displaying one or the other, so whichever one you
pick the tv will convert it back to native. Best to chose the one that your
tv actually displays, though.

Tom