Web data are experiencing a proliferation of video content for mobile platforms. This is accompanied by new advances in heterogeneous general purpose processor (GPP) cores embedded in mobile devices which offer a great opportunity to enhance both performance and energy efficiency of software (SW) video decoding. On the other hand, hardware (HW) video accelerators are more energy-efficient but are not flexible and their time-to-market is significant. In this context, this paper proposes a characterization methodology to investigate the performance and power consumption of two video decoding approaches on mobile platforms. The first one uses a HW decoder intellectual property (HDIP) in addition to a GPP (for the control). The second one is SW-based and uses only a heterogeneous multi-core GPP. The objective is to study the behavior of both video decoding approaches by comparing them and to understand why and in which case it is worth relying on the GPP rather than the HDIP. We also derive the optimal GPP configuration (number of cores and their frequency) that minimizes the energy consumption for a given video bit-stream on a given platform. The proposed methodology was applied on the HEVC video codec standard. In some state-of-the-art work figures, the SW video decoding consumes up to $1000\times$ more energy than HDIPs. Our results show that, for video resolutions of 1080p and lower and at the operating system perspective point of view, the HEVC SW decoding consumes on average less than $4\times$ more energy (mJ/Frame) than the HW one. Then, the more we scale up the resolution, the more we get the advantage of using the HW video decoding. Furthermore, the HEVC HW and SW decoders consume effectively less than 30% and 50% of the global power consumption of the tested platforms, respectively.

Web数据正经历着用于移动平台的视频内容的激增。这伴随着嵌入在移动设备中的异构通用处理器（GPP）内核的新进展，这为增强软件（SW）视频解码的性能和能效提供了巨大的机会。另一方面，硬件（HW）视频加速器更节能，但不灵活，而且上市时间很长。在此背景下，本文提出了一种表征方法，以研究两种视频解码方法在移动平台上的性能和功耗。除了GPP（用于控制）之外，第一个还使用硬件解码器知识产权（HDIP）。第二个是基于软件的，仅使用异构的多核GPP。目的是通过比较两种视频解码方法的行为来研究它们的行为，并了解为什么和在这种情况下值得依赖GPP而不是HDIP。我们还得出了最佳GPP配置（内核数及其频率），该配置可将给定平台上给定视频比特流的能耗降至最低。所提出的方法已应用于HEVC视频编解码器标准。在一些最新的工作图形中，SW视频解码最多消耗 所提出的方法已应用于HEVC视频编解码器标准。在一些最新的工作图形中，SW视频解码最多消耗 所提出的方法已应用于HEVC视频编解码器标准。在一些最新的工作图形中，SW视频解码最多消耗$1000\times$比HDIP耗能更多。我们的结果表明，对于1080p和更低的视频分辨率以及从操作系统的角度来看，HEVC SW解码的平均消耗小于$4\times$比硬件的能量（mJ /帧）多。然后，我们扩大分辨率的范围越广，就越能获得使用HW视频解码的优势。此外，HEVC硬件和SW解码器分别有效地消耗了不到测试平台全球功耗的30％和50％。