This paper addresses the optimisation problem of Huffman encoding in MPEG-4 Advanced Audio Coding stan- dard. At first, the Huffman encoding problem and the need of encoding two side info parameters scale factor and Huffman codebook are presented. Next, Two Loop Search, Maximum Noise Mask Ratio and Trellis Based algorithms of bit allocation are briefly described. Further, Huffman encoding optimisation are shown. New methods try to check and change scale factor bands as little as possible to estimate bitrate cost or its change. Finally, the complexity of old and new methods is calculated, compared and measured time of encoding is given.
The paper presents two techniques of balancing energy in ScaleFactor bands for Advanced Audio Coding. The
techniques allows the AAC encoder to get a better audio quality. The first one modifies Scale Factors assigned
to each band after the quantization whereas the second finds and changes offsets in the quantization - just
before rounding down. The implementations of the algorithms have been tested and results discussed. Results
show that these techniques significantly improve the quality. At last hardware implementation possibilities are
This article presents several hardware architectures of Advanced Audio Coding (AAC) Huffman noiseless encoder,
its optimisations and working implementation. Much attention has been paid to optimise the demand of hardware
resources especially memory size. The aim of design was to get as short binary stream as possible in this standard.
The Huffman encoder with whole audio-video system has been implemented in FPGA devices.
This paper presents complete optimized architecture of Advanced Audio Coder quantization with Huffman
coding. After that psychoacoustic model theory is presented and few algorithms described: standard Two Loop
Search, its modifications, Genetic, Just Noticeable Level Difference, Trellis-Based and its modification: Cascaded