Four new Diamond Standard VDO (ViDeO) processor engines have been customised for multistandard, multi-resolution video in SoC designs. Targeted specifically at mobile handsets and personal media players (PMPs), these video subsystems developed by Tensilica are fully programmable to support all popular VGA and standard definition (SD, also known as D1) video codecs with resolutions up to 720 x 480 (NTSC) and 720 x 576 (PAL). Among them are H.264 Main Profile, VC-1 Main Profile, MPEG-4 Advanced Simple Profile (ASP), and MPEG- 2 Main Profile, each of which is available from the company. Lower resolutions, such as QCIF, QVGA, CIF, and VGA, are supported as well.
The Diamond Standard VDO engines host all of the key videoprocessing functions in software on the cores, including the network abstraction layer, picture layer, slice layer, bit-stream parsing, and entropy decoding and encoding. This includes the computationally demanding CABAC (Context Adaptive Binary Arithmetic Coding) decoding in the H.264 Main profile decoder that’s either omitted by most other solutions altogether, or implemented in a separate and complex non-programmable hardware block, necessitating more than 700 MHz of general CPU workload.
By implementing CABAC in instruction set extensions, 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.