Stereo Coding Based On Spatial Perceptual Information

Compared to traditional stereo coding, intensity stereo coding can significantly reduce the bitrate for stereo and multi-channel audio. However, it produces sintolerable distortions can occur if intensity stereo coding is used for audio signals with the full bandwidth or wide spatial image. Binaural cue coding(BCC) can overcome these problems.Research indicates that the human perception of the auditory spatial image is largely determined by inter-channel level difference, inter-channel time difference, and inter-channel coherence. Based on this principle, BCC represents stereo and multi-channel audio signals with a single downmixed audio channel containing the signal components of all input audio channels. Additionally, BCC estimates ICLD, ICTD and ICC between the original audio channels and transmits parameters as side information to the decoder. According to side information, the decoder generates the ICLD, ICTD and ICC in decoder approximate those of the original audio signal. Since the side information contains less information than the original audio channel, the bitrate of BCC is as low as that of mono audio coding. The content of this thesis mainly includes the following parts:1. Analyze the influence that ICLD ICTD and ICC to audio image , given out their estimate method and fast arithmetic.2. Reference to other's work, put forward the completely BCC scheme.3. Discuss low Complexity BCC in detail, including subbands division, sum signal arithmetic, convolving in the STFT domain, perceptual Parameter quantization and coding, BCC decoding arithmetic, etc. Program simulation is implemented. Testing result is well. Implemented stereo audio have strong Spatial sense and low distortion.