Implementation of an object audio system based on MPEG-4 audio lossless coding on DSP

In this paper, we propose an object audio system on digital signal processor (DSP) that consists of MPEG-4 audio lossless coding (ALS) to provide high-quality audio. The complexity reduction in the designed object audio system is very critical issue because the system requires several MPEG-4 ALS decoders, as many as the number of objects. A method to efficiently use internal memory on DSP is suggested to overcome the high-complexity situation that happens with the use of external memory. A low-complexity finite impulse response (FIR) filter is also proposed because the short-term prediction filter in the MPEG-4 ALS decoder has the highest complexity in MPEG-4 ALS decoder blocks. A method for efficient use of internal memory is designed so that the critical data of MPEG-4 ALS decoders use internal memory as much as the size of the data for a decoder, and the internal memory is shared with the MPEG-4 ALS decoders. The proposed FIR filter reduces the complexity of the short-term prediction filter by 25% compared to direct convolution. A proposed method for an object audio system is evaluated on DSP; it consists of 12 objects. The proposed audio system has a reduction of complexity by 83% with the application of the two proposed methods, and the audio system operates in real time on DSP. This means that high-quality object audio can be serviced for multimedia products.