Perceptually Controlled Selection of Alternatives for High-Frequency Content in Intelligent Gap Filling

Par SVD, Disch S, Niedermeier R, Edler B. Perceptually Controlled Selection of Alternatives for High-Frequency Content in Intelligent Gap Filling. In: Convention Paper. Audio Engineering Society; 2025. Paper 10249. Available from: https://aes.org/publications/elibrary-page/?id=23093

@inproceedings{Par2025_23093,
  author = {Par, Steven van de and Disch, Sascha and Niedermeier, reas and Edler, Bernd},
  title = {{Perceptually Controlled Selection of Alternatives for High-Frequency Content in Intelligent Gap Filling}},
  note = {Paper 10249},
  year = {2025},
  month = oct,
  publisher = {Audio Engineering Society},
  url = {https://aes.org/publications/elibrary-page/?id=23093}
}

TY  - CPAPER
TI  - Perceptually Controlled Selection of Alternatives for High-Frequency Content in Intelligent Gap Filling
AU  - Par, Steven van de
AU  - Disch, Sascha
AU  - Niedermeier, reas
AU  - Edler, Bernd
M1  - Paper 10249
PY  - 2025
DA  - 2025/10/14
UR  - https://aes.org/publications/elibrary-page/?id=23093
PB  - Audio Engineering Society
LA  - en
AB  - When encoding audio at very low bitrates using a transform coding technique like AAC, the encoder may not be able to encode the full audio bandwidth with good quality. For this reason, bandwidth extension techniques have been proposed, like Intelligent Gap Filling, that copy low-frequency spectral bands to high frequencies and adjust their properties by a set of parameters. Although such methods provide a significant quality improvement, the selected bands and their interaction with neighboring bands may cause artifacts mainly due to misaligned tonal components. In this contribution, a new method is proposed to generate high-frequency content for Intelligent Gap Filling. It is based on creating non-linear distortions in the time-domain decoded core signal. For tonal signals, this will create a harmonic spectrum with potentially better tonal alignment. As a non-linearity, sign- and RMS-preserving squaring of the input signal between pairs of consecutive zero crossings is used. A perceptually controlled dynamic selection mechanism is investigated to chose between the alternatives of no extension, copy-up and non-linear distortion. Listening tests show that for some tonal items the dynamic selection obtains an improvement in audio quality.
ER  -