The concept of High Definition is a buzz word that has extended beyond where the terms are useful to most people. It is often hard for people to actually understand what HD formats mean and what they are used for. Contrary to standard belief, there are actually more than one format that is under the HD banner and they have different levels of resolution. Different companies are developing different formats, not all of which compress and produce images in "true HD." Here is a layout of some of the more common HD formats that digital video producers and directors are likely to encounter most in the coming years.
HDCAM is considered an HD format that is a version of the original digital Betacam. This tends to be a reliable and incredibly high quality image, and is currently used in feature filmmaking. The HDCAM format is used with the Sony CineAlta HDW-F900 camera, though many lower end digital video filmmakers may never utilize this camera. This utilizes both 1080i and 1080p and a variety of common film frame rates ranging from 23.98 frames per second to 30 FPS.
The HDCAM SR is a new version of this HDCAM format. This actually upgrades many of the details such as the new feature of allowing uncompressed color resolution to be recorded easily. This is used with several different cameras including the Sony CineAlta HDW-F950 and the Sony F23 CineAlta. You can expect frame rate options like 59.94 FPS, MPEG-4 audio compression, different compression methods for things like interlaced or progressive video, and over ten audio channels.
DVCPRO HD may be the type of HD format that more home videographers may be getting used to soon. The DVCPRO HD format, which was brought to us by Panasonic, uses a smaller over all bit rate and still maintains great picture. The DVCPRO HD design is going to be better known on consumer HD cameras like the Panasonic AG-HVX200. This camera is a broadcast quality machine, but is light weight and great for quick and easy shooting. The compression is going to be different between DVCPRO HD and formats like HDV because of a lack of temporal compression. This means that motion is going to end up coming through better on the DVCPRO HD. There are a variety of formats here that will record at 720p, 1080p, 1080i, and all at a range of different FPS. This also includes 4:2:2 chroma sampling, but is a little less in comparison to something like the HDCAM SR in terms of bits and the numbers of audio channels.
HDV is a common HD format that is being used by companies like Canon and Sony. What this does is essentially brings the HD platform to digital videotapes, which means that it does not exist as "true HD." HDV is much more practical for many home digital video producers, but it is not going to have near the resolution of formats like DVCPRO HD. This still has comparable numbers such as the ability to use 1080i, 1080p, 720p, and a few different frame rates. There is much lower bits, compression rates, audio channels, and chroma samplings than other HD formats.
HD D5 is also an HD format that puts the footage on D4 tapes. This will allow for different types of resolutions and frame rates and may give you more freedom than HDV. This is going to also be of a higher quality than HDV.