[Technology Report]
Lights, Camera, Process!
With an ever-expanding application base, digital video processors target performance needs through specialization and innovation.
After a decade of development and standardization efforts, digital video is now poised to take over broadcast television. With this transition, some digital video processor ICs are moving toward commodity status while others embrace innovation and diversification. The result of this shift is a growing range of product offerings as well as an open door to a host of new video applications.
General-purpose DSPs from companies like Analog Devices and Texas Instruments dominated the early years of digital video processing. Rapid evolution in video-compression technology as well as contending standards made designers seek the flexibility of a programmable solution while discouraging the development of specialized hardware.
With the stabilization of standards like H.264, MPEG-2, and MPEG-4 as well as the Federal Communications Commission mandate for conversion to digital broadcast television by 2009, specialized ICs became more cost-effective to develop and apply. Digital video processors then began to appear.
This sounds like the same pathway that many technologies follow: processor to hardware to commodity. But once digital video technology began to stabilize, it took a different path, or rather, many different paths.
Digital video began branching out beyond television into an array of application areas, engendering a growing variety of processing options. These range from video-augmented DSPs all the way to dedicated-function processors and coprocessors. A significant amount of intellectual property for system-on-a-chip (SoC) and FPGA design is available as well (see “Digital Video Processing IP,” p. 46).
A handful of application areas currently dominates the digital video processor market. The consumer broadcast digital television receiver market, naturally, is one of the largest in terms of volume. Commercial television, personal video, and video conferencing, all utilizing the Internet Protocol (IP) as the delivery mechanism, represent another major market. Other significant markets include equipment for studios, content providers, and video-based surveillance.
DIVERSITY BREEDS CHALLENGES Each of these application areas poses a different challenge for equipment developers as well as their processor vendors. Studio equipment along with both broadcast and network-based digital television receivers need high-performance, standardsbased processing at low cost. Surveillance applications also require high performance, but are more concerned with applications flexibility than with standards.
The IP-based handheld video market is somewhat less concerned with performance, due to lower expectations for video quality, but it’s acutely interested in low power. The communications part of this market is also focused on minimizing latency.
This range of applications and design requirements has produced a continual stream of new digital video processor introductions that shows no sign of abating. The consumer broadcast and network-based digital television receiver markets, in particular, are awash with processor introductions from companies like Freescale Semiconductor, Sigma Designs, STMicroelectronics, Texas Instruments, and Toshiba.
These companies seek to offer developers options that allow tradeoffs between high performance and low cost for different market segments. They also offer tradeoffs between highly specialized fixed and more flexible programmable digital video processing.
The highly targeted STMicroelectronics STi7111 set-top-box (STB) decoder chip combines a CPU for applications processing; decoders for H.264, MPEG-2, and VC1 data streams; and demodulators for satellite television signals. It also offers an Ethernet port for receiving video over IP networks.
Similarly, the SMP8564 STB decoder from Sigma Designs incorporates multiple processors, video-enhancement hardware accelerators, and audio subsystems on chip to handle all essential functions of an STB design (Fig. 1).
Such high integration is common for processors in the broadcast television market. The Toshiba TC90413XBG packs virtually all of the processing needed for a digital television receiver into one chip (Fig. 2). It needs only an audio amplifier, an LCD panel, and some memory as additional active components.
But along with such targeted devices, vendors offer many degrees of programmability as options. According to Gerard Andrews, applications processor product line manager at Texas Instruments, such offerings seek to address a wide range of applications beyond consumer video.
Reprints
