REDUCED COMPLEXITY CONVERTER SNR CALCULATION

摘要

The present document relates to audio encoding / decoding. In particular the present document relates to a method and system for reducing the complexity of a bit allocation process used in the context of audio encoding / decoding. An audio encoder (300) configured to encode an audio signal according to a first audio codec system is described. The audio encoder (300) comprises a transform unit (302) configured to determine a set of spectral coefficients (312) based on the audio signal. Furthermore the encoder (300) comprises a floating point encoding unit (304) configured to determine a set of scale factors and a set of scaled values (314) based on the set of spectral coefficients (312); and to encode the set of scale factors to yield a set of encoded scale factors (313). In addition the encoder (300) comprises a bit allocation and quantization unit (305 306) configured to determine a total number of available bits for quantizing the set of scaled values (314) based on a first target data rate and based on the number of bits used for the set of encoded scale factors (313); to determine a first control parameter (315) indicative of an allocation of the total number of available bits for quantizing the scaled values of the set of scaled values (314); and to quantize the set of scaled values (314) in accordance to the first control parameter (315) to yield a set of quantized scaled values (317). Furthermore the encoder (300) comprises a transcoding simulation unit (320) configured to determine a second control parameter (321) based on the first control parameter (315); wherein the second control parameter (321) enables a transcoder to convert the first bitstream into a second bitstream at a second target data rate; wherein the second bitstream accords to a second audio codec system different from the first audio codec system; and wherein the first bitstream comprises the second control parameter.