High definition TV to make its mark through compression innovations

Paul Boughton

The world of video is seen as the next great challenge in the industryand new players are coming through with come innovative architectures.

Established chip makers Conexant SystemsBroadcom and ST Microelectronics are all due to ship single chip HDTV decoders that use the latest MPEG4 part 10 (also called AVC and H.264) compression technology in set top boxes next yearbut alongside these are some new architectures. One of those was WISchip Internationala US start up which was bought by German TV chip maker Micronas last October.

WISchip’s DeCypher8100 decoder uses three MIPS cores with a mixture of programmable elements and hardwired accelerator blocks for functions such as CABCME and DCT all linked via a 32bit bus switch. This can handle one HD channel up to 1080 progressive (1080p requires significantly higher performance decode than 1080i) and an SD channel for picture in picturerecording on a VCR or distribution around the home.

The elegance of the architecture is that one of the MIP engines is used for a programmable Digital Right Management core that handles all the common encryption technologies such as AES and 3DES in hardware and the key management in software. This not only allows content to be decrypted and sent out over the HDMI link to the TV screenbut also

re-encrypted to be sent out over the Ethernet port to other devices or networked around the homestill encrypted. This is not possible with many other solutions.

The other two cores are used for the network stacktaking advantage of a expertise from Broadcom and the well established MIPS software infrastructurewhile the other core is used for the transport and demultiplxingallowing both current MPEG2 transport and the native MPEG4 formats to be handled.

“WISchip’s portfolio of products and important IP for HDTV from whatever sourcebe it broadcastIPTV or delivered from storage mediamakes the company the perfect complement for Micronas’ state-of-the-art HD display products” said Wolfgang KalsbachCEO of the Micronas Group. “WISchip has assembled a great team of industry experts in the field of advanced algorithms and SOC architectures. Its activities significantly strengthen our worldwide R&D efforts.”

The designs will be combined with Micronas’ own TV chips. “The combination of technologies and products from Micronas and WISchip will enable Micronas’ customers to quickly bring to market next-generation audio/video solutions for a broad range of productsincluding Integrated Digital HDTVsenhanced cablesatellite and terrestrial TV set-top boxespersonal video recorders (PVRs)next generation high definition DVD recorders (HD DVD and BluRay) and playersInternet Protocol (IP) set-top boxesIP AV streaming systems as well as IP surveillance cameras” said Hans-Jürgen Désorvice president of Consumer Products of Micronas.

Part of the expertise is in executionsays Jim Nguyendirector of marketing at WISchip who joined the company from Sigma Designs and MIPS before that. WISchip has built its own FPGA-based verification boards and run extensive hardware and software co-simulation so that drivers were ready before the chip went to the faband the company has an extremely high confidence that the chip will work first time. The fact that many of these blocks were already used in chips for the PC market also adds to the confidence.

One advantage is the lack of legacysays Nguyenas it allows them to build a very clean architecture without having to support legacy software. “I think it more good than bad at this point” he said.

Digital Signal Processing giant Texas Instruments is also aiming to replicate the success it has had in the GSM cellular phone market in the video worldbut it’s plans are under attack from a range of new and innovative architectures backed by some highly experienced industry players.

The Da Vinci ‘platform’ from TI aims to combine an ARM core (and possibly a MIPS core) with the latest digital signal processing core in a wide range of applicationsfrom portable video through surveillance systems to standard definition TV over phone lines and even high definition TV.

This is a similar approach to the OMAP platform for cell phones that now dominates the market with a single software and development infrastructuremaking it simple for companies such as NokiaSymbian and Motorola to develop operating systems to a standard set of APIs.

“We believe da Vinci will span the same applications in video as GSM” said Rich TempletonCEO of TI.

The key says Jean Marc DarchyDSP Systems director for Europe at Texas Instrumentsis the software. “The aim is to provide a lot of the software components such as Linux and WinCE (on da Vinci) and a series of other that are more targeting the embedded system world. We are providing the middleware and the user interface capabilities so with the first device we will attack the market with much more of a solution provider approach.”

But it is just the flexibility in software and ‘solution provider approach’ that is offering opportunities to othersmaller chip vendors. With a clean set of APIs that comes from not having to support legacy applicationsstart ups say they can offer a better solution.

“In the 1980s we had RISC and that was very exciting. I think video is the thing now” said Howard Sachsfounder of US start up Telairity and the man who developed the patent for Very Long Instruction Word (VLIW) technology while at Intergraph Sachs.

Despite being smallwith just 23 peoplethe company has a depth of experience with Sachs and Jim Meadlockfounder of Intergraph. That has led to Telairity offering the whole systemwith a wide range of software modules that customers can usesays Sachs.

It is that change that has attracted the attention of analysts. “H.264 is an important new standard for HD broadcastingand Telairity has positioned itself well with this architecture to take advantage of the demand for H.264 encoding equipment” said Michelle AbrahamPrincipal AnalystConverging Markets & TechnologiesMultimediaat In-Stat.


New chip

The new chipthe T1P2000is built on a 90nm process at Fujitsu and measures 10mmx15mm. It combines five independent vector/scalar coresa video controllerand a DRAM controller supporting an I/O bandwidth up to 5.3Gbit/s in the SoC. Each vector/scalar core features four vector pipes with independent hardwarean independent scalar unit128Kbytes of on-chip vector SRAMa 4Kbyte vector SRAM data cachean 8Kbyte scalar scratchpad memoryand a 32-Kbyte instruction cache.

At a clock rate of 668.25MHzor nine times the 74.25MHz 20bit video standardthe T1P2000 reaches a total sustained chip performance of 55.5GOPS.

Sachs is talking to the tier one encoder makers such as Tandberg Television and Harmonicboth of which use the high end TI DSPs at the moment.

“We are not going to take on TI head on – we will leverage a processor tuned for this marketand we believe that we can be very successful at itas the TI focus is on the handheld and a very broad market” he said.

“The architecture we have is a five processor architecture which will give a high definition TV real time encoder solution in 8 chips and one FPGAwhich is the same performance at 24 of TI’s chips. And those eight chips have perhaps 30percent spare capacity for other complex algorithms such as rate control.

The company is funded by Sachs and colleagues such as Meadlock with a few smaller investors. “We are interested in building a company and not so much in getting an immediate return” said Sachs.

The TV market is one focusand others include the HD DVD market that also includes Blu Ray recordable systemsas well as video over DSL phone linesall the areas that TI is targeting. “We expect to expand our architecture and software expertise into other markets that are very allied to the current one such as video surveillancemilitary systems and medical imaging” said Sachs.

The company is also taking a different tack on evaluations. “We are not going to run benchmarks” says Sachs baldly. “If they like the pictures that come outthen we will talk about their raw video streams. It’s all about the overall solutionnot about whether our DCT or motion estimation is adequate because there are so many facets to this problem.”

“The best processor benchmark is the customer's applicationand it is in this type of environment that we've designed and measured the capabilities of the Telairity-1 architecture” he said. “Lower prices for HD equipmentramping sales of HDTV receivers and monitorsand the availability of HD-DVD and Blu-Ray DVD players mean that HDTV has arrived.”

Yet another new approach is being taken by Neotiona French company that has patented the idea of using an MPEG4 AVC module in a CAM module. This is the slot in the back of a TV or payTV set top box that can take a PCMCIAcard with hardware for conditional access.

Neotion bought French chip designer Xeole of Sophia Antiolis 18 months ago and has now produced a transcoder that will take an MPEG4 AVC input and produce an MPEG2 stream in real time. While there initially doesn't seem to be a need for such a chipNeotion sees it being used to convert today’s MEPG2 set top boxes into tomorrows AVC boxes with a simple US$20 upgrade.

This is particularly appealing for the integrated digital TV makers who want to make one version of the set and regionalise it with a simple plug-in module by the distributor. This might seem a bit bizarrebut the company has a deal with Sony to use it.

The key is that the chip can be cheaper because it is not having to do a full video decode – it takes the MPEG4 AVC decode down to the intermediate I-frame rather than the full videoand then re-encodes to MPEG2. This means all the existing infrastructure of the IDTV or set top box can be usedand the Neotion chip only has to do half the job. The output has been tested against the decoders from STConexantNECFujitsu and NECsays Dominique

But Neotion has also capitalised on its internal skillsas the CEO used to run contract manufacturer SCM Microsystemsthe leading manufacturer of conditional access modules.

So 2mm high PCMCIA card holds the circuit board for the Neotion transcoder but will also take a smartcard for the CA system.

Networking

The idea can be extended with wireless networking. Plugging a module with an 802.11g front end into the IDTV – and all sets over 26in have to have these sockets – creates a link to a PC that can run a software MPEG4 encoderallowing video content on the PC can be displayed on the TV.

The new implementations of MPEG4 is driving innovation in digital video imagingwith new ideas and better ways of handling the videoproducing smallerhigher performance and more cost effective systems.

"

Recent Issues