CPU制造工艺(2)

to the requirements of professional high-performancecomputing (HPC) applications, but equally capable athandling consumer-level applications. From the cost-effective Intel Pentium 4 processor to the scalable,dependable Intel Xeon processor, real-time MPEGperformance requirements can be met at every leveland for a wide range of applications. The exceptionalperformance of Intel architecture platforms made itpossible for Ligos to create a flexible MPEG codec thatdelivers high quality without the expense of a dedicatedhardware encoder, giving broadcasters in the industryan ideal tool for cutting expenses without sacrificingspeed or precision.

operations on it. “Even within a single video file,” hesaid, “there are a number of processes involved inprocessing the encoding of the video, whether it bemotion estimation or a dual-pass routine or noisereduction to ensure higher quality. Demultiplexing all ofthose elements and then remultiplexing requires moreprocesses. We use hyper-threading so that even for asingle piece of media, we can process everything in realtime or faster. Our software is designed to the latest Intelarchitecture and to HT Technology such that on thelatest systems based on the Intel Pentium 4 processorsupporting Hyper-Threading Technology, we can takeadvantage of a single processor working two threads tosimultaneously encode those streams. A year ago, wewere running those two programs on dual-processormachines powered by Intel Xeon processors.”

Optimizing for the LatestGeneration Processors

Ligos employs the latest advances in microprocessortechnology to speed up both encoding andtranscoding applications. Hyper-Threading (HT)technology1, in particular, offers abundant opportunitiesfor performance boosting when manipulating digitalvideo signals, whether performing compression ortranscoding operations.

Specialized Instruction Sets

Both consumers and professionals benefit fromoptimizations that take advantage of progressivelyimproving Intel processor instruction sets, from Intel®MMX technology, Steaming SIMD Extensions (SSE),SSE2 instructions, to the expanded set of performance-oriented SSE3 instructions. Membership in Intel®

Developer Services and the Intel®Early Access Programfor the Pentium 4 processor gave Ligos engineers apipeline to resources for optimal tuning of their codec tothe emerging hardware platform. Communicationthroughout the development process with the IntelDesktop Product Group helped Ligos equip theirapplications with well-designed codecs optimized for thenewly released desktop processors at their launch dates.

Transcoding and Hyper-Threading Technology

“Transcoding is one of those things,” Robert SaintJohn, Marketing Lead at Ligos, said, “that will useevery available cycle to get the job done faster or athigher quality. Transcoding might involve one fileformat to another or from a file to signal output orfrom signal input to file. We will use every availablecycle to get that job done as fast as we can at thehighest quality levels possible. We absolutely use HTTechnology to perform efficient dual-channelencodes, as well as other operations that requiremultiple processes.”

Saint John pointed out that a segment of media typicallyconsists of multiple elements and each of thoseelements requires a different process to perform

Matching Performance and Parallelism

Performance and parallelism go hand-in-hand withvideo applications. For networked media applications,handling multiple pieces of content requires optimalperformance at the operating-system level, as well asalgorithms that take advantage of instruction-levelparallelism at the lowest levels of the middlewarelayers. The latest generation of Intel Pentium 4processors supporting Hyper-Threading Technologyprovides a capable home media server with theinherent advantages of parallelism. At the applicationlevel, networked media applications can takeadvantage of Hyper-Threading Technology to servemultiple streams of content to different devices.

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Networked media applications realize benefits inparallelism similar to the Ligos MediaRig application.MediaRig utilizes Hyper-Threading Technology on IntelXeon processors to improve performance for theprofessional market—transcoding multiple streams ofcontent to broadcast audiences.

While the home and professional applications areworlds apart, the underlying functionalities are quitesimilar, involving the transcoding of media streams inreal time. However, in comparison to networked mediamiddleware, MediaRig is a finely tuned applicationdesigned for a very specific task. Networked mediaserver applications for the digital home require a moregeneral-purpose design. Significant performanceadvantages can’t be achieved simply by spawningmore and more threads. In addition to streaming one ormore channels of video, a networked media applicationmay also be required to simultaneously transcode andstream multiple channels of audio and digital photoswhile sharing the processor time with typical officeapplications. While someone using an office applicationmight not notice a brief interruption in processoroperations, any pause in content delivery in an audio orvideo application is visually unacceptable. Techniquesemployed by Ligos ensure that the media beingdelivered is smooth, fluid and uninterrupted.

Where opportunities for application-level parallelismend, instruction-level parallelism begins. Broadcastapplications utilizing Ligos MediaRig can be tailoredto a specific hardware configuration designed togenerate a precise number of media streams, usingcodecs built to handle specific loads withoutdifficulty. In comparison, general-purpose mediaadapter middleware operates in a fairly unpredictableenvironment, where streaming video being deliveredto the television may compete with someone in thehome playing an action-adventure game or someoneburning MP3 music to disc. For this reason,

instruction-level optimizations at the codec level canmake the difference between a smooth-running setof applications and a disjointed, poorly presentedmedia experience.

MediaRig Enters theProfessional Market

In 2002, Ligos saw a viable strategic opportunity in thebroadcast and professional video market. Relying onthe rapidly increasing capabilities of hardware platformsbased on Intel architecture, Ligos engineered a systembased on their proprietary software to duplicate andenhance the functionality of existing DSP-basedMPEG-2 encoders, decoders and transcoders. With theeconomies of scale generating price/performance

Performance and parallelismgo hand-in-hand with videoapplications. For networkedmedia applications, handlingmultiple pieces of contentrequires optimal performanceat the operating system-level,as well as algorithms that takeadvantage of instruction-levelparallelism at the lowest levelsof the middleware layers.

advantages of as much as 50 percent on Intelprocessor-based platforms, Ligos found they coulddeliver professional broadcast functionality much morecost effectively than the competition and the MediaRigline of products was born.

The transcoding, encoding and decodingrequirements of MediaRig demanded a high-performance processor solution and the advantagesof multi-threaded operations had been wellestablished in enterprise and scientific applications.The performance gains achieved through Intel Hyper-Threading Technology on mainstream desktopcomputers powered by Intel Pentium 4 processorsproved an effective technique for gaining cost-effective performance on standard hardwareequipment. These benefits are even more noticeableon platforms powered by the high-performance IntelXeon processor family.

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