KR970071703A - Audio decoding method capable of adjusting complexity and audio decoder using the method - Google Patents

Abstract

The present invention relates to an audio decoding method capable of adjusting a complexity and a decoder using the audio decoding method. The audio decoder according to the present invention includes a bitstream analyzer for analyzing an encoded bitstream in an encoded mode according to a syntax and separating the encoded bitstream into information necessary for decoding and a bit allocation information decoder A sample inverse quantizer for inversely quantizing the quantized audio data of each divided band using the decoded bit allocation information, a scale factor decoder for decoding a scale factor for each of the divided bands, A multiplier for obtaining inversely quantized band division signals by multiplying the scale factors of the respective divided bands, a band limiter for removing signals of some upper band from the inversely quantized band division signals, Synthesizes the bands of the signals and converts them into time-domain audio data And a synthesis filter. Therefore, by adjusting the complexity of the synthesis filter, it is possible to implement a variety of decoders that can significantly reduce the amount of computation although the sound quality of the reconstructed audio is somewhat lower than that recommended by the MPEG-1 audio standard.

Description

Audio decoding method capable of adjusting complexity and audio decoder using the method

Since this is a trivial issue, I did not include the contents of the text.

FIG. 3 is a block diagram showing a configuration of an audio decoder according to an embodiment of the present invention; FIG.

Claims (9)

Analyzing the encoded mono-mode audio bitstream according to a syntax; Decoding the bit information and the scale factor allocated to the divided bands separated by the analysis step; Quantizing the quantized audio data of each of the divided bands using the decoded bit allocation information; Obtaining inversely quantized band division signals by multiplying the dequantized audio data of each of the divided bands by the decoded scale factor; Limiting the band by removing signals of some upper band from the de-quantized band-wise signals; And combining the bands of the band-limited band-split signals to convert the band-limited band-split signals into time-domain audio data. The method as claimed in claim 1, wherein, when the number of divided bands in coding is M, the amount of computation in the band combining step is reduced to 1 / Q of the MPEG-1 audio standard, (M / Q-1) th frequency band. The audio decoding method of claim 2, wherein the fast DCT structure is used in the band synthesis step. A bitstream analyzer for analyzing the encoded mono-mode audio bitstream according to a syntax and separating the audio bitstream into each information necessary for decoding; A bit allocation information decoder for decoding the bit information allocated to each of the divided bands separated from the bit stream analyzer; A sample dequantizer for dequantizing the quantized audio data of each divided band using the decoded bit allocation information; A scale factor decoder for decoding a scale factor for each of the subbands separated from the bitstream analyzer; A multiplier for obtaining inversely quantized band division signals by multiplying the dequantized audio data of each of the divided bands by a scale factor of each of the divided bands; A band limiter that removes signals of some upper band from the dequantized band split signals output from the multiplier to limit a band; And a synthesis filter for synthesizing bands of the band split signals output from the band limiter and converting the synthesized bands into audio data in a time domain. The apparatus of claim 4, wherein, when the number of divided bands in encoding is M, in order to reduce the amount of computation in the adaptive synthesis filter to 1 / Q of the MPEG-1 audio standard, M / Q-1) th band of the audio signal. 6. The audio decoder as claimed in claim 5, wherein the synthesis filter uses a fast DCT structure. Analyzing an encoded audio bit stream in a stereo mode according to a syntax; Decoding the bit information and the scale factor allocated to each of the divided bands separated by the analysis step with respect to the left channel, dequantizing the quantized audio data of each of the divided bands using the decoded bit allocation information, Obtaining inversely quantized band division signals by multiplying the decoded quantized audio data of each of the divided bands with 1/2 of the decoded quantized audio data; Decoding the bit information and the scale factor allocated to each of the divided bands separated by the analysis step with respect to the right channel and dequantizing the quantized audio data of each of the divided bands using the decoded bit allocation information, Obtaining inversely quantized band division signals by multiplying the decoded quantized audio data of each of the divided bands with 1/2 of the decoded quantized audio data; Adding the dequantized band division signals to the left channel and the dequantized band division signals to the right channel; And combining the band of the inversely quantized band division signals generated by the adding step and converting the combined band into audio data in the time domain. The audio decoding method according to claim 7, further comprising the step of limiting the band by removing signals of some upper band from the dequantized band division signals generated by the adding step, A possible audio decoding method. A bit stream analyzer for analyzing an encoded audio bit stream in a stereo mode according to a syntax and separating the audio bit stream into each information necessary for decoding; A first bit allocation information decoder for decoding bit information allocated to each of the divided bands in a left channel separated from the bit stream analyzer; A first sample inverse quantizer for inversely quantizing the quantized audio data of each of the subbands for the left channel using the decoded bit allocation information; A first scale factor decoder for decoding a scale factor for each of the subbands for the left channel separated from the bitstream analyzer; A first multiplier for obtaining inversely quantized band division signals by multiplying the left channel by the inverse quantized audio data of each of the divided bands and a scale factor of each of the divided bands; A first bit allocation information decoder for decoding the bit information allocated to each of the subbands for the right channel separated from the bit stream analyzer; The dequantization of the quantized audio data of each of the subbands for the right channel using the decoded bit allocation information may be performed by a second sample inverse quantizer; A second scale factor decoder for decoding a scale factor for each subband for the right channel separated from the bitstream analyzer; A second multiplier for obtaining, for the right channel, band-dequantized signals obtained by multiplying dequantized audio data of each of the split bands by a scale factor of each of the split bands by 1/2; An adder for adding the band-split signals de-quantized with respect to the left channel outputted from the first multiplier and the band-split signals dequantized with respect to the right channel outputted from the second multiplier; A band limiter that removes signals of some upper band from the dequantized band split signals output from the adder to limit a band; And a synthesis filter for synthesizing bands of the band split signals output from the band limiter and converting the synthesized bands into audio data in a time domain. ※ Note: It is disclosed by the contents of the first application.