It is a Chinese-developed processor for portable multimedia players. Compared to previous chips only supporting proprietary MTV or AMV video formats, current Rockchip players such as some Onda and Teclast players support Xvid video (up to QVGA resolution @24fps), FLV as well as various uncompressed audio formats (FLAC, APE) in addition to mp3.
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NB: The actual Mfg is Fuzhou Rockchip Electronics - most info about the actual chip design is in Chinese such as here
http://www.itime.cn/Article/mp3/apply/9946.shtm