Patent ID: 6553141
Filing Date: 2003-04-22
Classification: H04N

Abstract:
A method for transferring source data from a server to a client, said method comprising the steps of:generating, from said source data, transform data comprising spatially related coefficients such that a block of coefficients permit reconstruction of identifiable portions of said source data; generating, at a client, a request for at least a portion of said source data, said request defining a block of said coefficients and at least one quantization value; transferring, from said client to a server, said request; extracting, at said server, transform data defined by said request; quantizing, at said server, transform data in accordance with said quantization value to generate quantized transform data; compressing said quantized transform data to generate compressed data; transferring, from said server to said client, said compressed data; decompressing, at said client, said compressed data to generate quantized data; de-quantizing said quantized data to generate transform data; reconstructing said source data at said client from said transform data; generating, at said client, a second request for said block of coefficients, said second request including a first quantization value from said first request and a second quantization value for said block of coefficients; transferring, from said client to a server, said request; extracting, at said server, transform data defined by said block of coefficients; generating a first quantized coefficient block from said transform data using said first quantization value; generating a second quantized coefficient block from said transform data using said second quantization value; generating a first and a second de-quantized coefficient blocks by multiplying said first and second quantized coefficient blocks by said first and second quantization values, respectively; generating an incremental coefficient block by subtracting said first de-quantized coefficient block from said second de-quantized coefficient block; compressing said incremental coefficient block to generate a compressed incremental coefficient block; transferring, from said server to said client, said compressed incremental coefficient block; decompressing, at said client, said compressed incremental coefficient block to generate an incremental coefficient block; generating, at said client, a coefficient block for said second request by adding said coefficient block from said first request to said incremental coefficient block; and reconstructing said source data at said client from said coefficient block for said second request.