An efficient FGS to mpeg‐1/2/4 single layer transcoder with R‐D optimized multi‐layer streaming technique for video quality improvement

Abstract

The need for interoperability poses a challenge with the widespread use of multiple video formats. A Multi Layer Streaming‐Simplified DCT Domain Transcoder (MLS‐SDDT) is proposed to achieve efficient transcoding and video quality improvement. However, an efficient architecture is needed to handle drifting errors. The MLS‐SDDT algorithm addresses these issues by proposing: (1) an FGS compatible Simplified DCT Domain Transcoder (FGS‐SDDT) architecture for MPEG‐1/2/4 single layer transcoding, and (2) an R‐D optimized multi‐layer streaming technique for video quality improvement. To support efficient transcoding from FGS to MPEG‐1/2/4, the FGS‐SDDT adopts low complexity Simplified DCT Domain Transcoder (SDDT) architecture as an FGS compatible SDDT. To resolve the serious error‐drifting problem from SDDT, especially for heterogeneous transcoding, a mathematical analysis of the error‐drifting problem is provided and a solution by multi‐layer streaming is adopted. The multi‐layer streaming approach pre‐computes the errors according to the mathematical analysis and encodes the errors as the second enhancement layer for error compensation. For different network conditions, an R‐D optimized model is used to improve the bit allocation in the two enhancement layers for better R‐D performance. Our experiments show that the MLS‐SDDT can deliver 1.4∼7.0 dB PSNR improvement for MPEG‐1 and 1.9∼8.6 dB improvement for MPEG‐2 as compared to the SDDT. For FGS to MPEG‐4 single layer transcoding, the MLS‐SDDT can achieve minor PSNR loss (0.0 ∼ 0.4 dB) with lower computational complexity as compared to the SDDT approach.