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i and p

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Anonymous
November 4, 2004 4:41:11 PM

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.

More about : question

Anonymous
November 4, 2004 10:00:50 PM

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

the (i) is for interlaced, the (p) is for progressive.

Current analog Telvisions display 480 lines, new Digital High Defination
televisions are capable of displaying 720 to 1080 lines, therefore giving a
much better picture quality.

Now for your question the (i) and (p) stand for the way that the picture is
decoded in the television.
Normal Analog television is interlaced (i), that is: even lines, 2, 4, 6,
8... 480 are scanned in 1/60 second, then odd lines 1,3,5,7,9... 479 are
scanned in 1/60 second. Your eye puts together a complete picture 30 times
a second. This is a bit jerky at times, especially in "Live" sports such as
swimming at the Olympics.

Now progressive sends a complete picture every 60th of a second. You can
see how much smoother the picture would / could be.

There are lots better and more complete discussions available, but I thought
I'd try to give you an answer here.
Russ.



"Eddie G" <mickeddie at comcast.net> wrote in message
news:1pCdneBOmdxT6hfcRVn-uQ@comcast.com...
> What is the "i" and "p" in 480i, 720p, etc.? Not only what does it stand
> for, but technically speaking as well.
>
>
>
November 4, 2004 10:00:51 PM

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.
Related resources
Anonymous
November 4, 2004 10:53:25 PM

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

"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
November 5, 2004 12:55:53 AM

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

"Eddie G" <mickeddie at comcast.net> wrote in message
news:p uKdnWfhFMCQUhfcRVn-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
Anonymous
November 5, 2004 4:36:09 AM

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

"Eddie G" <mickeddie at comcast.net> wrote in
news:p uKdnWfhFMCQUhfcRVn-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
Anonymous
November 5, 2004 4:46:10 PM

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

I'ts personal... I have my LG LST3510 set to 1080i, and leave it. It will
do an automatic conversion if so set to go to what ever is being broadcast,
but I like it in 1080i best....
That's me personally.
Russ
>
> 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
>
>
>
Anonymous
November 5, 2004 7:25:26 PM

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

"Richard" <rfeirste at nycap.rr.com> wrote in message
news:10ol9tci73r3c93@corp.supernews.com...
> TV scanning started as progressive scan.

Maybe when it was experimental and not standardized, but the NTSC format was
created as interlaced in 1941 and stayed that way when "compatible color"
was standardized in the 50's. Even the first RCA broadcasts from 1939 on
were interlaced.

There is lots of NTSC history here:
http://www.williamson-labs.com/ntsc-fink.htm

Brad H
!