720p and 1080p explained

720p explained

720p is the shorthand name for a category of HDTV video modes. The number 720 stands for the 720 horizontal scan lines of display resolution (also known as 720 pixels of vertical resolution), while the letter p stands for progressive scan or non-interlaced.

Progressive scanning reduces the need to prevent flicker by filtering out fine details, so sharpness is much closer to 1080i than the number of scan lines would suggest. A 720p frame has about 1 million pixels. Compared to it, a 1080p frame has 2 million pixels so the amount of detail doubles. However in practice the difference between 1080p vs 720p is not as obvious as the one between standard definition vs high definition (480p vs 720p). For example a regular DVD isn’t even considered high definition because it is either 720×480 (NTSC) or 720×576 (PAL) but it looks much better than regular NTSC or PAL TV broadcasts and not as great as 720p. That being said, you do get more detail from 1080p than from any resolution if you have the “winning” formula for screen size, resolution and viewing distance – that is if you have the optimum conditions to get the most out of 1080p.

1080p explained:
The number 1080 represents 1,080 lines of vertical resolutions (1,080 horizontal scan lines), while the letter p stands for progressive scan (meaning the image is not interlaced). 1080p can be referred to as full HD or full high definition although 1080i is also “Full HD” (1920×1080 pixels). The term usually assumes a widescreen aspect ratio of 16:9, implying a horizontal resolution of 1920 pixels. This creates a frame resolution of 1920×1080, or 2,073,600 pixels in total.

The only pure 1080p content comes from high definition DVDs like Blue Ray and HD DVD. Regular DVDs are way below that, having just 480p or 576p. You also get HD content from TV broadcasts but for now only 1080i and 720p. Basically 1080i offers pretty much the same amount of detail as 1080p but the quality of fast moving scenes is a bit inferior to 1080p. To understand this better read the 1080p vs 1080i guide. 720p content will of course look the same (or very similar) on a 1080p screen as it does on a 720p screen because what also matters is the content resolution not just the screen resolution.

Here is a sample with the difference between 720p and 1080p:

480i - Total image resolution 337,920 pixels

480p - Total image resolution 337,920 pixels

720p - Total image resolution 921,600 pixels (roughly equivalent to a 1 mega pixel camera)

1080i - Total image resolution 2,073,600 pixels (equivalent to a 2 mega pixel camera)

1080p - Total image resolution 2,073,600 pixels (equivalent to a 2 mega pixel camera)

More lines is nice but don't forget about the 'p' and 'i' in the 720p, 1080i and 1080p. The letter is an abbreviation for the type of scan the TV uses -- 'p' stands for progressive and 'i' stands for interlaced.

Capturing Crystal Clear Images With Megapixel Technology

Megapixel surveillance is not a new concept — its applications and benefits are starkly clear. What has changed are smarter cameras, taking advantage of the added pixels and a better understanding of illumination in real life. In the first of a two-part report, A&S examines how smarter megapixel cameras are getting; the second part looks at best practices for optimal performance.

The big picture for megapixel surveillance cameras looks bright, in the wake of the recession. HD and megapixel cameras are expected to make up nearly 30 percent of network camera shipments in 2011, according to IMS Research. By 2015, it is forecast that more than 60 percent of network cameras shipped will be of megapixel resolution.

The resolution increase has a noted effect on the whole surveillance system. While a 2.1-megapixel or 1,080p HD image is six times larger than a D1 image, the additional pixels require a bigger pipe to transmit more data. The infrastructure and storage costs for megapixel are well-documented, with ROI and TCO being used as arguments in favor of bigger pictures. The fate of megapixel is linked to the future of IP networks, with HD forecast to make up most high-resolution cameras compared to megapixel, according to IMS.

Megapixel surveillance requires careful planning, but the benefits of added resolution boost the accuracy of analytics. Edge devices take advantage of faster processors, resulting in smarter use of pixels. Analytics can help reduce bandwidth, as an event will trigger video streaming, rather than constantly sending the same still images over the network. A more distributed architecture puts less strain on networks and makes life easier.

Clarity is the main driver for megapixel. “At the end of the day, you're putting in a security system to protect life and provide evidence in a court of law,” said Stephen Moody, Security Development Manager for ViS Security Solutions, an integrator in Ireland.

Cracking the Code
H.264 is the de facto standard compression for megapixel cameras, due to its efficiency in crunching large data files into smaller ones for transmission and storage. As compression evolved from M-JPEG's stills to MPEG-4 and now to H.264, a variety of profiles yield differences in performance. With 17 profiles in all, three are the most common: baseline, main and high, said Sachin Khanna, PM for CCTV, Bosch Security Systems.

By profile, the baseline is appropriate for video conferencing; the main profile is good for broadcast video; and high profile is most applicable for HD broadcast video. “H.264 requires a fair amount of processing power for encoding and decoding; this may limit the camera's frame rate and dictate the NVR platform to achieve the desired performance,” said Rich Pineau, CTO of Oncam Global.

Most H.264 profiles stem from 2-D applications, with not all profiles being capable of integration. “Even if both cameras are H.264 and the manufacturers are partners, the system could still not work,” said Patrick Lim, Director of Sales and Marketing for Ademco Far East. “The I/O and output are hard to integrate. Some engineers say it's easy to plug and play — there's no such thing.”