Video applications on mobile handheld devices are very challenging mainly due to the complex computational needs of video decoding and the limited capacity of batteries of handheld devices. The increasing number of codecs makes the situation even more perplexing for users trying to find the optimal video codes for playing on handheld devices. In this paper, we try to find the optimal video codecs from energy analyses of them on handheld devices. Various experiments have been done to investigate the effects from choices of codecs, file formats, and codec parameters. Keywords and phrases: codec, energy consumption, handheld device