Patent ID: 7203237

Claim:
A method of transcoding, comprising: (a) receiving encoded motion-compensated video including motion vectors and frame-DCT blocks; (b) downsampling said blocks as: (i) for an I-picture or P-picture DCT block, applying a two-dimensional inverse discrete cosine transform (IDCT) and then applying a downsampling with respect to the horizontal dimension; (ii) for a B-picture DCT block, applying a one-dimensional de-interlacing IDCT with respect to the vertical dimension of said block and then applying a one-dimensional IDCT and a downsampling with respect to the horizontal dimension; (c) applying inverse motion compensation from results from step (b); (d) after step (c), applying a downsampling with respect to the vertical dimension for the results of step (b)(i); (e) repeating steps (a)–(d) for further DCT blocks and motion vectors; (f) encoding the results of step (e).