HD TV Resolutions - 720p / 1080i / 1080p

[god2007]

I found a lot of misunderstandings regarding the 1080i HDTV resolution, in this and other forums. Many believe that 1080i equals to 540p. Therefore a separate thread on this subject is started. Like the viewing distance, admin may make this tread sticky, or a new sticky thread may be started by the admin himself. This subject is more important than the viewing distance and more confusing, particularly now that more and more ordinary folks is looking for HDTVs and the number of HD channels are on the rise.

Following is a link to a good article on the subject, even though it is two years old. ( just ignore the reference to TVs and model nos)

720p vs. 1080p HDTVs: 2009 update | Fully Equipped - CNET Reviews

Other relevant articles and information can be posted by other members.

 

[marsilians]

Seriously you have to search this forum. This has been discussed ad nauseum.

 

[god2007]

Seriously you have to search this forum. This has been discussed ad nauseum.

I do searched the forum and know there are many posts and replies. But I could not find a dedicated thread on this. Even now this topic came up many a times. My intention to to have a dedicated thread on this topic so that newbies can go straight in to it, like the sticky on viewing distances. IMO, this topic is more important than viewing distance.

If majority of the members are against a new thread on this, admin may remove this thread.

 

[just4kix]

Because interlaced scan displays half the frames per half second, while progressive scan displays all the fames per second, many people think that 1080i = 540p.

This is clearly wrong.

First of all there is nothing like 540p in the world of video. We have SD resolution which is 480i or 480p in NTSC and 576i or 576p in PAL.

Secondly the resolution itself. Restrictly strictly to widescreen 16:9 format the SD resolution is either 720x480 (sometimes 704x480) pixels for NTSC. For PAL, the resolution is 720x576 pixels (sometimes 704x576).

1080 i or p classifies as full high definition and the pixel resolution in this case is 1920x1080. As the article explains, interlaced scan does not reduce the resolution.

 

[prankey]

+1

Some people also equate 1080i as equivalent to 720p when both are altogether different formats with different benefits. 720p will have a resolution of only 1280x720p but can benefit from additional clarity and motion resolution as there would be no DEINTERLACING involved while displayed on an HDTV.

1080i has full HD resolution but during motion scenes the resolution gets proportionately reduced between 540 lines to 1080 lines if the pixels shift while processing each even and odd number of lines. A good deinterlacing algorithm and even motion compensation schemes like those on Panasonic Plasma and all the 100/200Hz processing LCD/LED TVs can help restore the lost resolution on 1080i frames.

 

[god2007]

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For PAL, the resolution is 720x576 pixels (sometimes 704x576).
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For PAL SD the resolution is 768x576 as per the direct capture from my HDTV box. Here is a still captured using VLC.

 

[prankey]

For PAL SD the resolution is 768x576 as per the direct capture from my HDTV box. Here is a still captured using VLC.

That is a strange resolution. Usually PAL expressed in digital format is 720x576i or p. However as there is no fixed number of column (or horizontal pixels) defined in PAL (as its only the number of horizontal scan lines), it can be captured in any resolution by a card.

 

[god2007]

That is a strange resolution. Usually PAL expressed in digital format is 720x576i or p. However as there is no fixed number of column (or horizontal pixels) defined in PAL (as its only the number of horizontal scan lines), it can be captured in any resolution by a card.

prankey, you are right. When checked with avicodec the actual video resolution is 720x576 only. But the VLC player snap reads 768x576. The computer did the trick while playing the file. In full HD video the resolution remains 1920x1080 in VLC snap as well. So I did not suspect.


BTW, it is not captured via a card. It is direct recording to usb pendrive by the box.

Here is an interesting link on the subject, if you are not already aware of it.

Standard-definition television - Wikipedia, the free encyclopedia.