Mpeg - 2 decoding with a reduced ram requisite by adpcm recompression before storing decompressed mpeg - 2 data, optionally after a while scanning algorithm

摘要

The video memory requisite of an MPEG decoder effecting a decompression of the I, P and optionally also of the B picture according to the MPEG compression algorithm and requiring the storing in respective buffers organized in said video memory of the respective MPEG- decompressed data, may be dynamically reduced by subsampling and recompressing according to a ADPCM algorithm at least the data pertaining to the I and P pictures before coding and storing them in the respective buffers. Subsequently, the stored data are decoded, decompressed and upsampled for reconstructing blocks of pels to be sent to a macroblock-to-raster scan conversion circuit.