Video codec circuit

The video encoding and decoding circuit is a circuit unique to MP4 machines. As shown in Figure 28-25, the main body of the video circuit of the ACER PM02 MP4 machine is
U5 TVP5150APBS. The composite video signal (CVBS) from the video and audio input socket is an analog signal. This signal is filtered by the filter circuit and sent to the ① pin of U5. The video signal is video decoded and A/D converted into digital video
in U5. signal
, and at the same time separate the field synchronization signal and clock
signal from the signal . These signals are sent to the CPU and decoder chip Ul for digital compression processing to compress a large amount of data redundancy, |;￡ for easy storage and playback Then decompression processing is performed. The MP4 machine adopts the MPEG4
compression standard for video data compression method. The power supply, system reset signal and crystal oscillator circuit provide necessary working conditions for U5.