Scalable video encoding with macroblock-level parallelism
- PDF / 3,380,369 Bytes
- 15 Pages / 595 x 794 pts Page_size
- 47 Downloads / 236 Views
RE SE A RCH
Open Access
Scalable video encoding with macroblock-level parallelism Sreeramula Sankaraiah*, Lam Hai Shuan, Chikkannan Eswaran and Junaidi Abdullah Abstract H.264 video codec provides a wide range of compression options and is popularly implemented over various video recording standards. The compression complexity increases when low-bit-rate video is required. Hence, the encoding time is often a major issue when processing a large number of video files. One of the methods to decrease the encoding time is to employ a parallel algorithm on a multicore system. In order to exploit the capability of a multicore processor, a scalable algorithm is proposed in this paper. Most of the parallelization methods proposed earlier suffer from the drawbacks of limited scalability, memory, and data dependency issues. In this paper, we present the results obtained using data-level parallelism at the macroblock (MB) level for encoder. The key idea of using MB-level parallelism is due to its less memory requirement. This design allows the encoder to schedule the sequences into the available logical cores for parallel processing. A load balancing mechanism is added to allow the encoding with respect to macroblock index and, hence, eliminating the need of a coordinator thread. In our implementation, a dynamic macroblock scheduling technique is used to improve the speedup. Also, we modify some of the pointers with advanced data structures to optimize the memory. The results show that with the proposed MB-level parallelism, higher speedup values can be achieved. Keywords: Video encoding; H.264; MB-level parallelism; Elapse time; Speedup; OpenMP; Barrier; Multicore architecture; Scalability; Load balancing
1 Introduction H.264 is an emerging video coding standard developed by the ITU-T Video Coding Experts Group (VCEG) and ISO/IEC Moving Picture Experts Group (MPEG) together with the partnership of Joint Video Team (JVT). H.264 has been developed with the aim of providing goodquality video at lower bit rates compared to previous video compression standards. H.264 also provides flexibility in serving broad range of video applications by supporting various bit rates and resolutions [1]. The improvement on bit rate efficiency of H.264 is at the cost of increased complexity compared to existing standards. The higher complexity of H.264 encoder results in longer encoding time [2]. This creates a need for improving the encoding time of the video for batch processing or real-time applications. Hardware acceleration or parallel algorithm for multicore processor is often needed to increase the *Correspondence: [email protected] Center for Visual Computing, Multimedia University, Cyberjaya, Selangor 63100, Malaysia
processing speed of the encoder. Parallel algorithm is becoming popular with the usage of multicore processors over the years even for mobile devices. Parallel algorithms for H.264 encoder design have been discussed in several papers [2-9]. These papers describe different levels of parallelism that can be applied on H.2
Data Loading...
