Balancing Transcoding Against Quality-of-Experience to Limit Energy Consumption in Video-on-Demand Systems

Dynamic adaptive streaming over HTTP (DASH) requires a video server to transcode each original video object to all the possible bit-rate versions, resulting in high CPU power consumption. To address this, we propose a new scheme that balances quality-of-experience (QoE) against transcoding energy. We start by introducing the concept of transcoding gain to express QoE achieved as a result of transcoding operation, by taking version popularity and QoE into account. We then propose two algorithms that determine which versions should be transcoded with the aim of maximizing the overall QoE. Experimental results show that the proposed scheme can effectively limit the amount of transcoding energy consumption.