Patent ID: 7809065

Claim:
An encoding system conversion device for converting a signal encoded in one encoding system into a signal of another encoding system, comprising: a decoder unit being fed with a compression-coded signal in an input buffer to decode the signal in a variable length decoder; an encoder unit being fed with a signal output from said decoder unit, having an orthogonal transform unit orthogonally transforming the input signal, having a quantizer quantizing coefficients resulting from the orthogonal transform unit, and having a variable length encoder compression-encoding the quantized coefficients to output the compression-coded quantized coefficients from an output buffer; and a transcoder controller having: means for monitoring at least the state of said output buffer, and means for modifying a quantization step in said quantizer (a) to decrease the code volume generated in said encoder if the stored volume in said output buffer exceeds a preset value to produce overflow, and for modifying the quantization step in said quantizer (b) to increase the code volume generated in said encoder if the stored volume in said output buffer is not up to said preset value to produce underflow.