1. In an interframe video hybrid coder which comprises means for transforming blocks of differential video pel data into blocks of transform coefficients, means for quantizing the transform coefficients of each transformed block, and means for entropy coding the quantized transform coefficients of each transform block, apparatus comprising: means for subdividing each block of differential pel data into smaller sub-blocks, said transforming means transforming each sub-block of each block and said quantizing means quantizing the transform coefficients of each transformed sub-block; and means for reconstructing a block of quantized transform coefficients from the quantized transformed sub-blocks.