In MP3/AAC encoders, the quantization parameter called scalefactor controls the quantization noise and the bitrate. Tuning these encoders would require a characterization of the rate-distortion function per subband, which seems to be available only in a parametric manner. In this paper, a fast bit allocation method for MP3/AAC encoder is presented. The resulting encoder is able to produce an ISO/MPEG compliant bitstream which can guarantee better audio quality. More importantly, the number of computational steps is greatly reduced as compared to the method recommended by the ISO/MPEG committee because the efficient bit allocation algorithm significantly reduces the number of iterations required. It was found that the efficient bit allocation algorithm works best when the bit rate demanded by the psychoacoustic model in order to keep the quantization noise below the masking threshold is almost equal to the operational bit rate.
Bang, Kyoung Ho; Lee, Keup Sup; Park, Young Cheol; Youn, Dae Hee
Affiliations: Samsung Electronics Co.; Yonsei University(See document for exact affiliation information.)
AES Convention: 118 (May 2005) Paper Number: 6381
Publication Date: May 1, 2005
Subject: Low Bit Rate Coding
No AES members have commented on this paper yet.
If you are not yet an AES member and have something important to say about this paper then we urge you to join the AES today and make your voice heard. You can join online today by clicking here.