FAQ: 720p versus 1080p

[Richard]

As a Signal Source
DTV broadcast: At this time only 720p and 1080i are used for broadcasting HD content. While the DTV system supports 1080p at 24 or 30 frames per the ATSC specification no broadcaster is using it, no DTV receivers are 1080p capable for analog video and no one knows for sure if a receiver with HDMI will support it either. At this time it is assumed if a broadcaster were to use the 1080p HD format that the receivers will work but downcovert it to 1080i. This is largely untested and therefore unknown since inexpensive test equipment does not exist to inspect what we expect and without a broadcaster sending it there is nothing to expect at this time.

Satellite or Cable: Just recently satellite has begun broadcasting 1080p at 30 or 24 frame. This is provided as a Premium service for movies. Please check with your provider to find out what is available and if any other services are required. At this time cable is not offering any 1080p services.

Blu-ray: Supports 720p at all frame rates. While it could support 1080p 60 frame content none is available and only 24 or 30 frame native is being used. Blu-ray players provide a 1080p 60 frame output but that is derived and converted from the original 24 or 30 frame content on the disc.

PC, PS3 and Xbox 360: A PC can easily provide a 1080p output. The frame rate will be directly related to the original content with PC gaming being the most likely source of higher and consistent frame rates provided your PC has enough processing horsepower to deliver it. PS3 offers numerous titles but not all are 60 frames and a new technique is being used to adjust frame rate on the fly from 30 to 60hz to prevent or reduce hardware limitations that cause strobing or momentary freezing. Xbox 360 has only a few 1080p titles and the hardware will have more difficulty providing 1080p gaming at higher frame rates.

1080p Consumer HDTV Display
In nearly all cases a display with this specification will have a native pixel matrix of 1920x1080 perfectly matching the HD 1080 standard. Buyer beware and inspect what you expect; Hitachi pulled a marketing and product tier fast one not long ago on their plasma line by providing a less expensive panel with a native pixel matrix of 1280x1080 calling it 1080p and another more expensive panel with a native pixel matrix of 1920x1080 calling it Tru1080p.

Most broadcasters are using the 1080i HD format and blu-ray adds the 1080p HD format which perfectly matches a 1080p display creating a beneficial response called 1:1 pixel mapping. A 1:1 pixel mapped display provides the best detail you can get with out any overscan. To take full advantage of a 1080p display and get the proper response with a PC requires you set the picture format option correctly for 1:1 pixel mapping and use a viewing distance that is close enough to resolve the detail. For HD the generic rule of thumb is 3 screen heights, the height of the viewing screen times 3. A viewing distance many use to help hide errors with HD and SD while retaining some detail performance is 4 screen heights. This is critical if you are spending money on HD detail performance because most viewers use 6-10 screen heights. At 6 screen heights there is little if any benefit over using a less expensive 720p LCD product and at 10 screen heights there is none.

1080p displays are reserved for the mid and upper tiers of a manufacturers product line at this time.

720p Display
It would be wonderful to tell sports fans that a 720p display would be a great choice but in the current market you can