An optimized design of aerial-video encode is presented to realize simultaneously real time compression for two PAL videos on an industrial embedded computer. The design chooses Discrete Cosine Transform (DCT) to decorrelate the image data. After comparing several kinds of fast DCT algorithms, AAN algorithm is optimized and implemented, and the base of the optimization is presented. In addition, the search method of Variable-length Code (VLC) table is also optimized. By optimizing the two largest computational algorithm modules in the scheme, DCT and VLC table,a 768×576 color video frame can be compressed in 8 ms with P4 3.0G CPU. Under the compression ratio of 32∶1, the Peak Ratio of Singnal to Noise(PSNR) of the design reaches 29.47, which is extremely close to the performance of the wavelet algorithms, so it guarantees the decoding quality of image. The experimental results show that the design reaches a better balance among compression speed, compression ratio and compression performance in video encoding, and it can satisfy the requirements of the aerial-video compression.