As an extension of H.264/AVC, Scalable Video Coding (SVC) provides flexible adaptation to heterogeneous networks and end-users, which provides great scalability for applications such as video conferencing. However, due to the existence of legacy H.264/AVC-based systems, transcoding between AVC and SVC becomes necessary. Currently there are few works done on AVC-to-SVC spatial transcoding, and re-encoding method involves high computational cost. This paper proposes a low-complexity coarse-level mode-mapping based AVC-to-SVC spatial transcoder for video conferencing applications. First, to omit unnecessary motion estimations (ME) for layers with reduced resolution, an ME skipping scheme based on AVC mode distribution is proposed with an adaptive search range. After that an adaptive coarse-level mode-mapping method is presented for fast mode decision. Finally, motion vector (MV) refinement is introduced for further lower-layer time reduction. As for the top layer, direct encapsulation is proposed to preserve better quality and another scheme involving inter-layer predictions is also provided for bandwidth-crucial applications. Simulation results show that proposed transcoder achieves up to 90.6% time reduction without significant coding efficiency loss compared to re-encoding method.
|出版ステータス||Published - 2011 12月 1|
|イベント||Asia-Pacific Signal and Information Processing Association Annual Summit and Conference 2011, APSIPA ASC 2011 - Xi'an, China|
継続期間: 2011 10月 18 → 2011 10月 21
|Conference||Asia-Pacific Signal and Information Processing Association Annual Summit and Conference 2011, APSIPA ASC 2011|
|Period||11/10/18 → 11/10/21|
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