TI and Qualcomm Lead For example, Texas Instruments is currently sampling its OMAP V2230, the company’s first standard processor with a 3G baseband. In addition to the integrated baseband, the V2230 offers excellent multimedia performance. The chip includes a powerful ARM11 CPU that has plenty of cycles to spare after implementing the WCDMA baseband protocols. These cycles can be used for audio, video, or graphics calculations. For outstanding multimedia performance, the V2230 includes two special-purpose engines. The image/video accelerator (IVA) can perform MPEG4 video encoding or decoding at a full 30 frames per second (fps) at up to VGA resolution (640x480). This provides a TV-like video experience on any phone screen and even if the phone is plugged into an external monitor. The V2230 also includes a 3D graphics engine capable of rendering 1 million polygons per second, delivering games with quality similar to the original Sony PlayStation. For even better performance, Qualcomm is sampling the initial members of its MSM7000 line, a family of handset processors that integrate CDMA or WCDMA basebands. These chips include an ARM11 CPU as well as a video engine and a 3D engine. The video engine provides 30fps video at up to VGA resolution. The 3D engine, of Qualcomm’s design, codeveloped with ATI, renders up to 4 million polygons per second. Hardware vs. Software At speeds of up to 400MHz, the ARM11 can perform audio, video, and graphics in software, providing acceptable video and graphics for most handset displays, which are rarely more than QVGA (320x240) resolution. One could question the need for multimedia engines in addition to this fast CPU. Indeed, Freescale’s newest handset processors, which appear in the RAZR and other popular Motorola phones, include an ARM11 CPU but have hardware for only video encoding, doing all other multimedia tasks in software. This software approach has the benefit of flexibility: as audio and video codecs evolve and new ones emerge, software can be modified to support them. But even when using ARM’s special multimedia instructions, software video codecs require significantly more battery power than custom video hardware. Some video engines are completely hardwired, eliminating the overhead of fetching and decoding instructions. Others use a customized processor that is optimized for video; these processors can often be upgraded for changes in the codec. In either case, the specialized hardware is more efficient than the ARM CPU, reducing power consumption. Without a specialized engine, watching video on a phone can quickly drain the battery, even with a small screen. Graphics, particularly 3D, poses a similar problem. Geometry calculations typically require floating-point math, which can be very time-consuming on a standard ARM CPU. Shading, lighting, and rendering are also complicated. A hardware 3D engine is much more efficient at these tasks, providing much better graphics performance. Alternatively, the 3D engine will greatly reduce power consumption at the same image quality. Because ARM now licenses the PowerVR engine, adding 3D acceleration to a handset processor is fairly simple. Raising the Bar Many multimedia phones today still use a separate multimedia chip. For example, Motorola is the biggest customer for ATI’s mobile graphics chips, which boost 3D and video performance. Broadcom’s Cellairity chip set includes the company’s own video chip (the same one used in Apple’s Video iPod). This approach is fine for adding multimedia to an existing design and creating a new high-end model. But extra chips add extra cost, power, and board area to a handset design. Integrating multimedia acceleration into the main handset processor solves this problem. As handset processors move into 65nm manufacturing technology, the transistor budgets are big enough to include multimedia engines. Companies that have already developed these engines on a separate chip, such as Broadcom, will have an easier design task than companies that must develop new architectures. TI and Qualcomm, the two leading vendors of handset processors, have taken the lead in integrating and delivering processors with multimedia acceleration. These vendors have the revenue to invest in developing new technologies at the high end. As cell-phone users become more excited about watching video and playing games, other chip vendors will also need to deliver multimedia handset processors.
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