They company name, as well as the product names probably don’t mean much to you, however what they do is quite important to your impending HD lifestyle. They are both SoC or system-on-a-chip systems that can do real-time HD encoding, transcoding, and decoding.
They have MPEG-2 and MPEG-4 decoders, audio processors, and graphics acceleration built into them. they are being made for set top boxes for both satellite and cable boxes, the 4120 is aimed at cable, with the 3120 being aimed at satellite.
They can do real time HD encoding at 1920×1080 pixels too. Other than displaying HD content on your display, other benefits of these chips are that they should lower the disk space required to store recorded content on DVR boxes, and they can even make it easier to transcode content into a size/format suitable for various portable media devices.
STB SoC does real-time HD encode/transcode [via linuxdevices]