Patent ID: 9208789
Filing Date: 2015-12-08
Classification: G10L

Abstract:
1. An audio encoder configured to encode at least one frame of an audio signal at a first target data rate in accordance with an E-AC-3 codec system, thereby generating a bitstream indicative of encoded audio content including quantized mantissas, said encoder comprising: a transform subsystem coupled and configured to determine spectral coefficients indicative of audio content of the frame of the audio signal; a floating-point encoding subsystem configured to determine mantissas and encoded exponents based on the spectral coefficients; a bit allocation and quantization subsystem configured to determine a first control parameter indicative of an allocation of available bits for quantizing the mantissas in accordance with the E-AC-3 codec system, and to quantize the mantissas in accordance with the first control parameter to determine the quantized mantissas; a bitstream packing subsystem coupled and configured to generate the bitstream at the first target data rate such that said bitstream is indicative of a second control parameter and encoded audio content of the frame, said encoded audio content including the quantized mantissas; and a transcoding simulation subsystem configured to simulate transcoding, said transcoding including decoding of the encoded audio content of the frame to generate decoded data including de-quantized mantissas and re-encoding of the decoded data at a second target data rate in accordance with an AC-3 codec system to generate a second bitstream indicative of re-encoded audio content including re-quantized mantissas, wherein the transcoding simulation subsystem is configured to execute an iterative bit allocation process to determine the second control parameter such that said second control parameter is indicative of an allocation of available bits for quantizing the de-quantized mantissas to generate said re-quantized mantissas during generation of the second bitstream in accordance with the AC-3 codec system at the second target data rate, wherein each bit allocation iteration of the iterative bit allocation process assumes a candidate allocation of available bits determined by a different candidate second control parameter of a set of candidate second control parameters, the set of candidate second control parameters having been predetermined by statistical analysis of results of bit allocation processing of audio data in accordance with the E-AC-3 codec system assuming the first target data rate, and results of bit allocation processing of the audio data in accordance with the AC-3 codec system assuming the second target data rate.