When it comes to resolutions, one might get a bit confused from all the numbers and specifications. In this guide I will explain the differences in 1080p vs 1080i.
Many plasma TVs as well as other types of HDTV have their screens rated as having a native resolution of 1080p and/or supporting 1080p and 1080i resolution. There is a difference between native and supported resolution and I will explain this focusing especially on 1080p vs 1080i.
Because I respect your time I am going to tell you from the start the conclusion: there is not much difference between 1080p vs 1080i and you shouldn’t give to much thought to this.
Native vs Supported Resolutions
Other than HDTVs that have a native resolution (real resolution) of 1080p, most of the other HDTVs (rated as having a native resolution of 720p) support 1080p. This is because they can accept 1080p video feed. That means you can watch a high definition DVD like Blue Ray (which is 1080p) but you only see the amount of detail specific to 720p. Basically most of the HDTV on the market support many resolutions. They can display 1080p, 1080i, 720p, 720i, 480i, etc. because they resize the picture to their actual native resolution. Flat panel displays are in nature progressive. Even if you watch a interlaced (1080i) video feed on a plasma or LCD TV, its internal processing system actually converts it to progressive.
1080p vs 1080i Scan Modes
The “p” letter in 1080p stands for progressive while “i” letter in 1080i stands for interlaced. These are two modes to build a picture on a TV. There are fundamental differences between the two but practically for the viewer the difference is in most cases unnoticeable. If you want to understand how progressive and interlaced work you can read in the Plasma TV & HDTV Resolution guide. When talking about progressive vs interlaced (1080p vs 1080i) you refer to the video source resolution not the display native resolution. All displays support both progressive and interlaced scan so it’s nonsense to compare them at display level or compare displays based on 1080p and 1080i.
Now, with the content source in mind rather than the TV, in very practical terms progressive gives you a sharper picture for fast motion scenes like sports and action movies. For example think at a tennis ball flying through the air – in 1080p its edges will be sharp while in 1080i if you pay close attention you will notice a slight blur to the edges of the ball as it flies through the air. However, unless you pay attention to the edges of the moving objects you will probably not notice the slight blurred edges from 1080i. For content without fast moving scenes there is no visible difference.
One note I must make here is that the type and quality of your HDTV can affect the sharpness of the moving scenes more than the scan mode used. For example if you are watching sports using 1080p feed on an LCD TV with a not too great refresh rate (higher than 5ms) the motion blur will be more noticeable than if you would watch the same content on a plasma TV using 1080i feed. This is because the refresh rate of the plasma is better than that of the LCD – a reason that recommends plasma TVs for watching sports (and sports are usually broadcasted in 720p vs 1080i).
Amount of Detail
The amount of detail you get on the screen is the same for both 1080p and 1080i. Though the amount of information (data throughput) transmitted through the cable is higher in the case of 1080p, the number of pixels you actually see it’s the same – 1920×1080.
Practical Comparison Between 1080p and 1080i
The difference between 1080p vs 1080i is not something to worry about. In fact you shouldn’t even bother too much about it. When referring to the data source (e.g. TV broadcast) you don’t even have a choice because at this time there is no 1080p HDTV broadcast. The only used HDTV broadcast formats are 1080i and 720p. When it comes to buying a plasma TV (or any HDTV for that matter) there is still no practical difference because their native resolution is either 1080p or 720p. So a 1080p vs 1080i discussion can be done only while referring to content resolution not display resolution.