A video decoder is an electronic circuit, often contained within a single integrated circuit chip, that converts base-band analog video signals to digital components video. Video decoders commonly allow programmable control over video characteristics such as hue, contrast, and saturation. A video encoder performs the inverse function of a video decoder; it converts raw (uncompressed) digital video to analog video.
The input signal to a video decoder is analog video (composite or S-Video) that conforms to a standard format such as NTSC or PAL. The output digital video may be formatted in various ways, such as 8-bit or 16-bit 4:2:2, 12-bit 4:1:1, or BT.656. Usually, in addition to the digital video output bus, a video decoder will also generate a clock signal and other signals such as:
Functional blocks
The main functional blocks of a video decoder typically include these: