There are many misconceptions associated with the term “HD." Yes, it does refer to a higher video resolution than standard-definition. Yes, it is commonly used in reference to 1080p or 1920x1080p. But no, that does not mean that 1080p is always better than 720p, or that any other high-definition videos are not as high “quality" as 1080p. We can't stress this fallacy enough. Many people aren’t well educated on the ins and outs of video resolution, the main differences between 1080p and 720p, and what 1080/50p and 1080/60p represent. Here are a few quick lessons you should know and relay to your coworkers.
1080HD vs. 720HD
In regards to general broadcast, meaning HD television and most mobile device video that include the majority of video viewers, 1080HD AND 720HD are used for different purposes. 1080HD is an example of spatial resolution, or containing more pixels. 720HD is an example of temporal resolution, or containing more frames per second. 720p is primarily used for sports because of how much movement is being done during airtime, whereas 1080p is used for movies that move at a much slower pace and can emphasize more pixels per frame. Horizontal line resolution refers to the amount of “bars” or “lines” that make up an individual frame. The idea is that the more lines per frame the better the resolution, because the more colors and shades it’s able to cover.
Also, 720p does not require a change in original transmission systems, therefore people are not always eager to switch to 1080p, in which they would be obligated to purchase new transmission systems to suffice. 39 networks in the US still use 720p.
1080i vs. 720p
720p has the advantage over 1080i (interlaced, used primarily for TV) because it reduces the number of artifacts during the transfer from a 24 fps video. This means that less data is lost during the compression process. When a codec is compressing a video to save storage space, 1080i has more noticeable differences, maybe visual image blocking or a lack of lighting. In contrast, 720p compresses media more efficiently, and therefore still appears to be in its best form.
RESOLUTION vs. SHARPNESS
Video sharpness is not solely based on pixels. Apart from the underlying theme of spatial or temporal resolution, external forces that can affect video sharpness are:
optical quality of camera lens
camera’s contrast range
digital signal processor of camera
camera movement and positioning during filming
Sharpness has more to do with the picture your camera is able to catch instantaneously, while the resolution has more to do with the post process of transcoding and editing your video for its intended audience.
Thin raster codecs are incomplete videos that don’t include all of the original pixels to be considered “HD.” Instead of 1920x1080 or 1280x720, thin rasters are recored in resolutions such as 1280x1920, 1440x1080, and 960x720. They are stored for later playback in full raster or complete video that is considered standard HD.
1080/50p AND 1080/60p
The 50p and 60p are in reference to the framerate, or frames per second. 50p displays 50 frames per second in a video, while 60p displays 60. Although these numbers seem high thus causing better quality, they are actually very limited for final distribution. Neither can be broadcasted in HDTV. Neither can be played on the majority of mobile devices. 30p is the highest framerate that can be displayed on general broadcast. What’s the use of 50p and 60p then? Slow motion videos, that are later conformed to 30p or below. The Hobbit trilogy used 48 fps and the result was a very animated looking feature, which in their case was intentional, and pretty cool.
I hope we were able to clear up some of your confusion regarding video resolution. Resolution technology is improving every year, and it’s difficult to keep up with the best practices to create and maintain high quality videos. Pay attention to the latest updates and trends in the industry, and you’ll be able to capture beautiful footage for whatever your production needs may be.
1. 1080HD is not better than 720HD, they each have their strengths and weaknesses
2. Perceived sharpness is determined by the camera, whereas resolution is determined during post processes
3. A Thin raster codec is an incomplete HD video
4. 1080/50p and 1080/60p cannot be used in final distribution, but are effective in capturing slow motion
5. This stuff isn’t that complicated! Spread the knowledge!