An image encoding apparatus is configured to encode image data comprising a sequence of unencoded blocks of pixels into a sequence of encoded blocks of pixels in a predetermined image encoding format. The cold devices have to be taken out after a predetermined period and cooled again to recycle. A lamp holder is integrally mounted onto the socket base for detachably retaining the LED lamp. 08, a focal length f of the objective lens satisfies a condition: 1. A cover is used to support the input ends of the input shaft and the output shaft. In some embodiments, each of the probe messages includes a training sequence, and information included in the one or more response messages enables selection of one of a number of possible modulation schemes to be used.