Video size conversion and transcoding from MPEG-2 to MPEG-4

Abstract

A transcoder architecture that provides the lowest possible complexity with a small error, e.g., for converting an MPEG-2 bitstream into an MPEG-4 bitstream. The transcoder reads header information from an input bitstream and provides a corresponding header in the new format for the output bitstream. In one embodiment, a low complexity front-to-back transcoder (with B frames disabled) avoids the need for motion compensation processing. In another embodiment, a transcoder architecture that minimizes drift error (with B frames enabled) is provided. In another embodiment, a size transcoder (with B frames enabled) is provided, e.g., to convert a bitstream of ITU-R 601 interlaced video coding with MPEG-2 MP@ML into a simple profile MPEG-4 bitstream which contains SIF progressive video suitable for a streaming video application. For spatial downscaling of field-mode DCT blocks, vertical and horizontal downscaling techniques are combined to use sparse matrixes to reduce computations.

Dependencies are inferred from the claim text.