This paper proposes a novel energy-efficient multimedia delivery system called EStreamer. First, we study the relationship between buffer size at the client, burst-shaped TCP-based multimedia traffic, and energy consumption of wireless network interfaces in smartphones. Based on the study, we design and implement EStreamer for constant bit rate and rate-adaptive streaming. EStreamer can improve battery lifetime by 3x, 1.5x and 2x while streaming over Wi-Fi, 3G and 4G respectively. • Hoque et al.over a period of time and then sent together as one burst to the client using all the available bandwidth. In this way, the WNI is kept active only for a short period of time to receive the burst, instead of keeping the interface always active. When the burst size exceeds the playback buffer, there is packet loss. Therefore, the maximum size of a burst, or equivalently the length of a burst interval, is tuned based on an acceptable range of packet loss [Korhonen and Wang 2005].Today HTTP over TCP is by far the most prevalent set of protocols used for streaming [Guo et al. 2006]. Traffic shaping saves energy with TCP-based streaming as well [Hoque et al. 2011]. TCP-based streaming differs from the case of UDP-based streaming in one major way: TCP is a reliable protocol. When the player buffer becomes full, data accumulates into the TCP receive buffer. As a result, an arbitrarily large burst, which is larger than the playback buffer, can be used without any packet loss. However, the exact impact on the energy consumption of smartphones is not well understood. In this article, we first study the interplay between the burst size and the power consumption of smartphones. Specifically, we model the energy consumption of WNIs for bursty TCP traffic. We show that the power consumption of a smartphone decreases when the receiving burst size increases and as long as the client device can accommodate the entire burst. In contrast, the power consumption rapidly increases, if the burst size is too large compared to the available buffer space at the client.As a proof of concept, we design and implement an energy-efficient multimedia delivery system called EStreamer. It determines an energy-optimal burst size so that smooth playback of the streaming applications is not distorted. EStreamer relies on standard TCP feedback from the client. We thoroughly evaluate EStreamer through measurements with real streaming services. We focus on two aspects: (a) the potential to save energy in smartphones using Wi-Fi, 3G (HSPA) and 4G (LTE) and (b) the impact on the radio access network (RAN) signaling load when using a cellular access network.Concerning the first aspect, we measure the energy savings in four different smartphones while streaming from popular streaming services via EStreamer, such as Internet radio, YouTube, and Dailymotion. The results demonstrate that the largest energy savings can be achieved with Wi-Fi (65%), followed by 4G (50-60%), after which comes 3G (38%). It is also shown that a client can achieve similar range of energy sav...