Other video applications
DVD Players
In addition to playing DVDs (which are based on MPEG-2 video compression), DVD players are expected to handle MP3 and WMA audio, MPEG-4 video (for DivX Video), JPEG images, and so on. Special playback modes such as slow/fast forward/reverse at various speeds are also expected. Support for DVD Audio and SACD is also popular.
A recent enhancement to DVD players is the ability to connect to a home network for playing content (music, video, pictures, etc.) residing on the PC. These “networked DVD players” may also include the ability to play movies from the Internet and download content onto an internal hard disc drive (HDD) for later viewing. Support for playing audio, video, and pictures from a variety of flash-memory cards is also growing.
How It Works
Looking at a simplified block diagram helps envision how video flows through its various operations. Figure 1.4 is a simplified block diagram for a basic DVD player, showing the common blocks. Today, all of this is on a single low-cost chip.
FIGURE 1.4. Simplified block diagram of a basic DVD player.
Digital Media Adapters
Digital media adapters connect to a home network for playing content (music, video, pictures, and so on) residing on a PC or media server. These small, low-cost boxes enable content to be easily enjoyed on any or all televisions in the home. Many support optional wireless networking, simplifying installation.
How It Works
Figure 1.5 is a simplified block diagram for a basic digital media adapter, showing the common blocks. Today, all of this is on a single low-cost chip.
FIGURE 1.5. Simplified block diagram of a digital media adapter.
Digital Television Set-Top Boxes
The digital television standards fall into seven major categories:
- ATSC (Advanced Television Systems Committee
- DVB (Digital Video Broadcast)
- ARIB (Association of Radio Industries and Businesses)
- IPTV (including DVB and ARIB over IP)
- Open digital cable standards, such as OpenCable
- Proprietary digital cable standards
- Proprietary digital satellite standards
Originally based on MPEG-2 video and Dolby® Digital or MPEG audio, they now support more advanced audio and video standards, such as MPEG-4 HE-AAC audio, Dolby® Digital Plus audio, MPEG-4.10 (H.264) video, and SMPTE 421 M (VC-1) video.
How It Works
Figure 1.6 is a simplified block diagram for a digital television set-top box, showing the common audio and video processing blocks. It is used to receive digital television broadcasts, from either terrestrial (over-the-air), cable, or satellite. A digital television may include this circuitry inside the television.
FIGURE 1.6. Simplified block diagram of a digital television set-top box.
Many set-top boxes now include two tuners and digital video recorder (DVR) capability. This enables recording one program onto an internal HDD while watching another. Two tuners are also common in digital television receivers to support a picture-in-picture (PIP) feature.
Standards organizations
Many standards organizations, some of which are listed below, are involved in specifying video standards.
Advanced Television Systems Committee (ATSC)
Association of Radio Industries and Businesses (ARIB)
Consumer Electronics Associations (CEA)
Digital Video Broadcasting (DVB)
Electronic Industries Alliance (EIA)
European Broadcasting Union (EBU)
European Telecommunications Standards Institute (ETSI)
International Electrotechnical Commission (IEC)
Institute of Electrical and Electronics Engineers (IEEE)
International Organization for Standardization (ISO)
International Telecommunication Union (ITU)
Society of Cable Telecommunications Engineers (SCTE)
Society of Motion Picture and Television Engineers (SMPTE)
Video Electronics Standards Association (VESA)
Instant summary
Implementing video on today's emerging products is a complex and challenging problem. There are many different facets and requirements to master. These include: