Format Terminology (page 3)
HD Formats
HDV: 720p and 1080i
JVC launched the first HDV camcorder, the GR-HD1, before HDV even had a name or a standards body associated with it. It was the first consumer camcorder that could record 720p video. Sony launched the HDR-FX1 the next year, the first consumer 1080i camcorder. All HDV camcorders record MPEG-2-compressed bitstreams to standard Mini DV tapes; however, the use of HD-grade tape is recommended because HDV bitstreams are much more susceptible to the effects of dropouts on the tapes.
AVCHD: 720p and 1080i
AVCHD represents one of the first video formats released to consumers that does not have a specific type of media associated with it. AVCHD writes MPEG-4 AVC bitstreams to devices such as memory cards, hard drives or optical discs (usually 8cm DVDs). MPEG-4 AVC itself is also an excellent distribution format-read more about it below.
Distribution Formats
The way we watch video has also changed. With digital formats came numerous playback options, from handheld devices to sophisticated large screens. We'll take a look at a few of them and their application. Distribution formats have variable resolutions.
Windows Media
In 1991, Microsoft released the first version of Windows that could play multimedia files. Since then, it has released a player, an encoder and a streaming video server. WMV, first introduced in 1999 with Windows Media Player 7, is a widely-popular proprietary encoding scheme developed to compete with Real. It comes with every copy of the Microsoft Windows operating system and is capable of playing back at high-definition resolutions.
H.264 / MPEG-4 AVC
Developed by the Motion Picture Experts Group (MPEG) as part of the MPEG format, H.264 is commonly referred to as MPEG-4 AVC (Advanced Video Coding). The H.264 reduces the bitrate of its predecessor, MPEG-2 (or H.263) by nearly 50 percent, allowing transmission of higher-definition video over the same bandwidth.
MPEG-2
MPEG-2 is, at the moment, ubiquitous. It's the format used to encode audio and video onto DVD and it's the format that broadcast digital television stations use. It uses a lossy compression algorithm to search for redundancies in images and frames (realizing that one frame of video is usually remarkably similar to the ones immediately before and after it) and discards some of the information. Its predecessor, MPEG-1, is used to create VCDs (video-compact discs) which, while popular in Asia, never broke in the U.S. due to the low playback quality, though many DVD players will play them.
Real
RealVideo was released by RealNetworks in 1997, and was a popular early method of distributing video, especially streaming video, which slowed down wait times by buffering a portion of video and allowing playback and downloading to take place simultaneously, instead of making the viewer wait for the entire video to download before playing. RealVideo files usually end with the extension .rm.
What's Next?
Formats didn't change much in the 1980s and 1990s, but now we have so many choices that it can be hard to figure which is best for your needs. This new millennium is going to enter into its second decade soon, and what's coming down the pike is anyone's guess. Care to comment? Write us about your predictions at editor@videomaker.com and reference this article in the subject line.
Contributing Editor Kyle Cassidy is a visual artist who writes extensively about technology.
