[10] About Video

DVD-Video

Subset of DVD specs, even though normally term "DVD" refers to this particular format.

DVD-Video is a standard developed by DVD Forum and specifies how video should be stored on optical DVD disc. DVD-Video specs allow two different kind of video encoding algorithms to be used: MPEG-2 and MPEG-1. Virtually all DVD-Video discs use MPEG-2 format, mostly because of its superiority over MPEG-1 in terms of video quality.

WMA

WMA stands for Windows Media Audio. A proprietary audio format owned by Microsoft, part of Microsoft's Windows Media technology.

Initially intended to combat the increasingly popular MP3 format, WMA was supposed to be Microsoft's answer to digital music. With the massive influx of constant bitrate, high quality, low file size MP3s flooding the Internet, it soon became clear to Microsoft that they would not be a direct competition for the format.

Thats not to say Microsoft didn't put their heart and soul into development of this audio format. Its configurable to be cbr, vbr and lossless audio encoding for a wide variety of options.

Encapsulated in an ASF container, WMA has one ability that seems to attract more and more businesses and allows this format to stick around. Thats the easy inclusion of DRM or Digital Rights Management directly into the WMA file. This ASF container also gives the WMA two file options. (.wma for strictly audio and .asf for features simliar to ID3 tags in MP3s)

WMV

WMV stands for Windows Media Video -- developed and controlled by Microsoft.

WMV is a generic name of Microsoft's video encoding solutions and doesn't necessarily define the technology what it uses -- since version 7 (WMV7) Microsoft has used its own flavour of MPEG-4 video encoding technology (not very surprising, it's not compatible with other MPEG-4 technologies..). DivX ;-) video format is originally based on hacked WMV codec.

The latest versions of WMV (now, summer 2005, the latest one is called WMV10) don't have much in common with MPEG-4 anymore, but use Microsoft's own video encoding technologies instead.

3GP

3GP is the name for both a video standard designed for mobile phones and the name of the Container used to store video used in the standard. It was developed by a group of companies and standards organizations from Europe, North America, and Asia called 3GPP for 3rd Generation Partnership Project. The purpose of the project was developing a mobile video standard compatible with 3G (3rd Generation) GSM mobile phone systems.

The Container
The 3GP container format is based on the MP4 format defined in MPEG-4 Part 14, but modified to add less Mixings overhead to obtain smaller file sizes. Both MPEG-4 Part 2 (SP and ASP) and Part 10 (AVC / H.264) video can be stored in the 3GP container, as can AAC and MP3 audio. In addition, H.263 video and AMR-NB, AMR-WB, and AMR-WB+ audio, all of which were developed for video conferencing, may be used.

The Format
3GP is designed for effieciency to make it suitable for Streaming across mobile phone networks and storing on mobile devices with very littel storage capacity. Video rarely exceeds a Resolution of 320x240 (or 368x208 for widescreen), and is usually 176x144 or 176x120. Audio will usually be encoded as either MP3 or AAC-LC (Low Complexity). Framerates for most mobile devices are Limited to 15fps.

QuickTime

Video (and audio) container format developed by Apple. QuickTime is like AVI or ASF, because it doesn't define the actual compression technology the video has to use, but just defines the video structure instead.

Despite this, term QuickTime is normally used to refer to Apple's own (or licensed, in both cases mostly meant for streaming) video encoding technology that used to produce pretty bad video quality -- something that could be compared to Real Video format.

Recently (since 2002), Apple has started using MPEG-4 video encoding on its QT streams, producing much better, if not excellent, video quality. Reason for this has been the huge demand from Hollywood to come up with an universal standard -- such as MPEG-4 -- that would produce good quality video for broadband use.

TiVo

TiVo is name of a company that offers a very popular brand of stand-alone digital video recorder (DVR). It sells DVR devices which allow the user to record television programming for later viewing. The word "TiVo" itself has been used to describe this process regardless of the brand of DVR or method; "I will TiVo 24".

DVR-MS

DVR-MS is a proprietary audio and video file format developed and solely owned by Microsoft. It uses the MPEG-2 standard Compression for video and audio compresses using MPEG-1 layer II. This format extends standards by adding metadata within the compression to allow room for information about the content as well as Digital Rights Management (DRM).

The DVR feature in Windows Media Center Edition saves recorded broadcasts in this format and with the added DRM, if the program is flagged as copyrighted, it will automatically append DRM standards on the media and only allow it to be played on the machine that recorded it. Files recorded without DRM can be moved and played back on any machine with Windows XP SP1 and up, so long as the Windows Media Player is version 9 with hotfix 810243 applied. Recently, with the release of Media Player 10, Microsoft included a transcoder within MP10 that allows users to convert non-DRM files from DVR-MS to WMV and allowing this file to be synched with portable media devices. This move apparently was to give more functionality to their Zune player released in late 2006.

There are several third-party applications that can convert DVR-MS to other formats and Mac OS X has a free utility called MPlayer that will load DVR-MS files.

Real Video

Streaming video format developed by RealNetworks. RealVideo is probably the most popular streaming video format in the world, although its quality is horrible if you compare it to MPEG-4-based formats like DivX ;-) or WMV. Quality compares to QuickTime quality.

RMVB

RMVB is a RealMedia Variable Bitrate file. RMVB is one of the newest file formats created by Real Networks and it has grown a pretty large following since its introduction due to its smaller file sizes yet still comparable quality when compared to other formats such as Xvid and DivX.