As a result of improvements in wireless communication technologies, a multimedia data streaming service can be provided for mobile clients such as PDAs and cellular phones. Because mobile devices have low computing power and work on a low network bandwidth, a transcoding technology is needed to adapt the original streaming media for mobile environments. To provide quality of service, original encoded media are transcoded within limited time and transmitted to clients without ceasing and jittering phenomena. In particular, when large-scale mobile clients demand streaming services, load distribution methods among distributed transcoding servers have a tremendous impact on the total number of quality of service streams. In this paper, a new load distribution method is proposed based on transcoding time estimation with transcoding servers' information, movie information and target transcoding bit-rate. In experiments, the proposed method produces the best performance scalability according to the increase of transcoding servers.