Low complexity real-time video transcoders for mobile video applications

This paper proposes low complexity real-time video transcoders based on both H.264 (AVC) and MPEG-4 which are suitable for mobile video applications. The transcoders proposed are PT (Picture Type Transcoder) and ST (Syntax Transcoder) and are used for video upload, delivery and video conference applications. In PT, relationship among PSNR, QP values and code length is obtained for H.264 baseline profile (BP) by simulation experiment to determine suitable QP values. Further, video mixing function for displaying multiple pictures at the same time in video conference application in which the proposed PT can be applied is described. The proposed PT and ST are implemented on a high-performance DSP, and complexity of PT and ST is compared with that of CPDT (Cascaded Pixel Domain Transcoder) for both H.264 BP and MPEG-4 simple profile (SP) cases. The complexity of the proposed PT and ST is very low. The complexity of PT is less than 1/3 of CPDT at both 64 kbps (QCIF) and 384 kbps (CIF) in H.264 BP.