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).

主权项

1. An audio encoder configured to encode a frame of an audio signal according to a first audio codec system, thereby yielding a first bitstream at a first target data-rate; wherein the audio encoder comprises a processor configured to perform as:
a transform unit configured to determine a set of spectral coefficients based on the frame of the audio signal; a floating-point encoding unit configured to
determine a set of scale factors and a set of scaled values, based on the set of spectral coefficients; andencode the set of scale factors to yield a set of encoded scale factors; a bit allocation and quantization unit configured to
determine a total number of available bits for quantizing the set of scaled values, based on the first target data-rate and based on the number of bits used for the set of encoded scale factors;determine a first control parameter indicative of an allocation of the total number of available bits for quantizing the scaled values of the set of scaled values; andquantize the set of scaled values in accordance to the first control parameter to yield a set of quantized scaled values; a transcoding simulation unit configured to derive a second control parameter for enabling 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; wherein the transcoding simulation unit is configured to derive the second control parameter from the first control parameter; and a bitstream packing unit configured to generate the first bitstream comprising the set of quantized scaled values, the set of encoded scale factors, the first control parameter and the second control parameter wherein the transcoding simulation unit is configured to derive the second control parameter from the first control parameter alone.