H.264/AVC baseline profile decoder complexity analysis

Abstract

In this paper, we study and analyze the computational complexity of a software-based H.264/AVC baseline profile decoder. Our analysis is based on determining the number of basic computational operations required by a decoder to perform the key decoding subfunctions. The frequency of use of each of the required decoding subfunctions is empirically derived using bitstreams generated from two different encoders for a variety of content, resolutions and bit rates. Using the measured frequencies, estimates of the decoder time complexity for various hardware platforms can be determined. A detailed example is provided to assist readers in deriving their own time complexity estimates. We compare the resulting estimates to numbers measured for an optimized decoder on the Pentium 3 hardware platform. We then use those numbers to evaluate the dependence of the time complexity of each of the major decoder subfunctions on encoder characteristics, content, resolution and bit rate. Finally, we compare an H.264/AVC-compliant baseline decoder to a decoder that is compliant with the H.263 standard, which is currently dominant in interactive video applications. Both "C" only decoder implementations were compared on a Pentium 3 hardware platform. Our results indicate that an H.264/AVC baseline decoder is approximately 2.5 times more time complex than an H.263 baseline decoder.

Parallelism Analysis of H.264 Decoder and Realization on a Coarse-Grained Reconfigurable SoC

“…These sub-tasks account for 71% of the baseline profile decoder's time complexity [30]. After decoupled control-intensive and computeintensive part, these sub-tasks share the following properties: separation of the compute intensive responsibilities from the control-intensive responsibilities; an intensive and regular calculation mechanism in the inner MBs (all of the data in one MB follows the same computing regulation); and a relative independence of data.…”

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“…An approach that addresses not only motion compensation, but the entire H.264 decoding process is presented by Horowitz et al in [17]. The paper presents an execution time estimation for the H.264 baseline profile.…”

H.264/AVC deblocking filter based on motion activity in video sequences

“…Performance analysis of H.264 deblocking filter shows that it reduces the blocking artifacts significantly at low bit rates [5]. However, it is highly computationally complex, as it takes one-third of computing resources of the decoder [6]. The main reason for high computing complexity of filter is heavy conditional processing on block edge and pixel level required for filtering decision, and to select one type of filter out of two filters.…”