STI5512 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'STI5512' PDF : 23 Pages View PDF
CONFIDENTIAL STi5512
Graphics and display subsystem
The display unit is part of the MPEG video decoder. It can overlay several display planes, as shown in Figure 3 on
page 7.
It takes the decompressed MPEG video data and performs the following functions:
• Optionally perform horizontal resampling of both luminance and chrominance data
• Reconstruct vertical data to create 4:2:2 sample format
• Generate on-screen display bit map for superposition onto picture output
• Allow sub-picture decoder output to be mixed onto picture output
• Optionally perform anti-flicker and anti-flutter filtering
• Optionally perform vertical resampling of both luminance and chrominance data
• Still picture plane with graphics capability
• 2D block move to copy rectangular sections of the display
• 4:4:4 chroma resolution for RGB output.
• 4:2:2 chroma resolution for CVBS output
• Separate control on OSD between CVBS and YC on one hand and RGB and YUV on the other
The sub-picture decoder can also be used as a hardware cursor unit. The priority of the sub-picture is first raised by
programming a register so it is above all the other display planes. A cursor can be defined using an optionally
compressed (run-length encoded) bitmap stored in external SDRAM. The bitmap can be any size up to a full screen.
Per-pixel alpha-blending factors can be defined for each cursor to provide anti-aliasing with the background. The cursor
is then moved around using register writes into X and Y coordinate registers.
The digital video data is fed to the PAL/NTSC/SECAM encoder subsystem.
PAL/NTSC/SECAM encoder
Integrated into this subsystem is all the digital processing and the digital to analog convertors required to process the
digital video output from the MPEG video decoder and produce RGB, YUV, YC and CVBS analog outputs. The output
of the teletext interface is filtered and re-inserted into the blanking interval in this subsystem.
Programmable Transport Interface
The transport demultiplexing function is performed in a programmable hardware module, the programmable transport
interface (PTI). Its operation is as described below.
The input interface may select between either a LinkIC stream or an IEEE 1394 controller as the source for the
transport stream. Data packets from the input interface are input into a FIFO while the PID is checked to see if it is
currently selected for processing or is to be discarded. A selected packet is parsed by the module to determine its type
and to extract data from it. If the packet is encrypted using the DVB Standard the correct key is written into the DVB
decryption core in the transport module and the packet is decrypted.
After parsing and descrambling the packet, the data is either transferred to buffers in external memory or directly to the
MPEG audio and video decoders. If the audio and video data is buffered then the data can be transferred by DMA from
the buffer to the MPEG decoders.
DVB standard sections are filtered by a set from 32 possible 8-byte filters to look for a match. Matching sections are
then transferred to memory buffers for processing by software.
Error conditions, system time clock recovery, and control of the hardware module are handled by software running on
the ST20.
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