| 摘要 |
A video, audio and graphics system uses multiple transport processors to receive in-band and out-of-band MPEG Transport streams, to perform PID and section filtering as well as DVB and DES decryption and to de-multiplex them. The system processes the PES into digital audio, MPEG video and message data. The system is capable of decoding multiple MPEG SLICEs concurrently. Graphics windows are blended in parallel, and blended with video using alpha blending. During graphics processing, a single-port SRAM is used equivalently as a dual-port SRAM. The video may include both analog video, e.g., NTSC/PAL/SECAM/S-video, and digital video, e.g., MPEG-2 video in SDTV or HDTV format. The system has a reduced memory mode in which video images are reduced in half in horizontal direction only during decoding. The system is capable of receiving and processing digital audio signals such as MPEG Layer 1 and Layer 2 audio and Dolby AC-3 audio, as well as PCM audio signals. The system includes a memory controller. The system includes a system bridge controller to interface a CPU with devices internal to the system as well as peripheral devices including PCI devices and I/O devices such as RAM, ROM and flash memory devices. The system is capable of displaying video and graphics in both the high definition (HD) mode and the standard definition (SD) mode. The system may output an HDTV video while converting the HDTV video and providing as another output having an SDTV format or another HDTV format.
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