Overview: DATASHEET TW2851
4-Channel A/V Decoder with Multiplexer/VGA/LCD Display Processor for Security Applications FN7743 Rev. 0.00 August 17, 2012 The TW2851 is a fully integrated A/V decoder, multiplexer, and display processor chip. It has eight CVBS analog inputs fed into four internal high quality NTSC/PAL video decoders. It has four digital input ports supporting various type of input format, including four BT 656 inputs, two BT 601 inputs, or one 1120 playback input. It has one optional VGA display controller or LCD panel controller, two CVBS display, one digital SPOT output, two digital recorder outputs, and one digital display output. Every output has its associated graphic overlay function that displays bitmap for OSG, single box, 2D array box, borders, privacy mask, and mouse cursor.
The four built-in video decoders include four antialiasing filters, 10bit Analog-to-Digital converters, proprietary digital gain/clamp controller, and high quality Y/C separator to reduce cross-noise. Associated with each video decoder, there are builtin motion, blind, and night detectors to provide alarm signals, a noise reducer to reduce the impulse noise, and 3 sets of downscalers to provide proper video size into the display, record, and SPOT multiplexers.
The TW2851 MUX function selects video inputs from any video decoder/ digital inputs to any of recording / SPOT / VGA display / CVBS display outputs flexibly. The recording multiplexer supports frame / field and byte-interleaved multi-channel video streams in the format of BT 656, BT 1120 to interface with external video pression CODEC. The frame / field allocation of each channel can be flexibly configurable in the multi-channel video stream.
