Video processor engines designed for media devices
Claiming to have solved one of the "grand challenges" of video system design, Tensilica Inc. announced a family of software-based video processor engines for mobile handsets and personal media players.
The Diamond Standard VDO processors handle multistandard, multiresolution video in SoC designs and can be programmed to support popular video codecs. Tensilica has even scaled the H.264 Main Profile mountain.
"This is a fully programmable solution that can run pretty much any video standard that you can dream of, including Main Profile H.264, which has been one of the grand challenges for video system designers," said president and CEO Chris Rowen.
Tensilica said its four processor subsystems, deliverable as Verilog RTL, support all popular VGA and standard-definition codecs with resolutions up to 720 x 480 (NTSC) and 720 x 576 (PAL) pixels. In addition to H.264 Main Profile, this includes MPEG-4 Advanced Simple Profile and MPEG-2 Main Profile. Lower resolutions are also supported.
The VDO engines host key video-processing functions in software, including the network abstraction layer, picture layer, slice layer, bitstream parsing and entropy decoding and encoding. This support includes the computationally demanding context-based adaptive binary arithmetic coding (Cabac) decoding in the H.264 Main Profile. By implementing Cabac in instruction-set extensions, Rowen said, Tensilica was able to create a low-megahertz and power-efficient version of Cabac in less than half the area of a typical Cabac hardware block.
"Cab (taxi?)ac is one of the reasons that H.264 is fundamentally preferred to earlier video standards," Rowen said. "Unfortunately, just to decode the bitstream on an ordinary processor at DVD resolution takes over 700 Mips of performance. Other solutions either can't do it at all or have a separate hardware block that does it. We've invented extensions that make it painless to do Cabac, requiring no additional hardware."
The family comes in four flavours. The Diamond 381VDO is a decode-only solution for Baseline and Simple profiles; Diamond 383VDO will decode and encode Baseline and Simple profiles; Diamond 385VDO performs decode only for Main and Advanced Simple profiles; and Diamond 388VDO encodes and decodes Main profiles.
Tensilica said it used its Xtensa configurable- and extensible-processor technology to create dual-core subsystem blocks for the Diamond Standard VDO family. The architecture includes one Xtensa processor configured as a stream processor, optimised for serial processing of video data, and another as a pixel processor. Interprocessor communication is via a 128-bit interface.
Tensilica has defined more than 400 video-specific instructions to boost performance over general-purpose DSPs or 32-bit micro- processors. These instructions are optimised for the most performance-intensive algorithms used in video processing, including Cabac, the company said. According to Tensilica, the new family requires a smaller area and consumes less power than competing products.
Diamond Standard VDO engine hardware and software were created in a joint development pact with Ittiam Systems, an Indian company.
Pricing starts at Rs.1.37 crore ($300,000) for a single-use license for the Diamond 381VDO. Decoders and encoders are priced separately starting at Rs.30.04 lakh ($66,000) for the MPEG-2 decoder. The Diamond 388VDO hardware and all software will be available by the end of March.
- Dylan McGrath
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