CONF motlicek:TSD:2007/IDIAP Non-Uniform Speech/Audio Coding Exploiting Predictability of Temporal Evolution of Spectral Envelopes Motlicek, Petr Hermansky, Hynek Ganapathy, Sriram Garudadri, Harinath EXTERNAL https://publications.idiap.ch/attachments/papers/2007/motlicek-TSD-2007.pdf PUBLIC https://publications.idiap.ch/index.php/publications/showcite/motlicek:rr06-30 Related documents Tenth International Conference on TEXT, SPEECH and DIALOGUE (TSD) 2007 IDIAP-RR 06-30 Unlike classical state-of-the-art coders that are based on short-term spectra, our approach uses relatively long temporal segments of audio signal in critical-band-sized sub-bands. We apply auto-regressive model to approximate Hilbert envelopes in frequency sub-bands. Residual signals (Hilbert carriers) are demodulated and thresholding functions are applied in spectral domain. The Hilbert envelopes and carriers are quantized and transmitted to the decoder. Our experiments focused on designing speech/audio coder to provide broadcast radio-like quality audio around 15-25kbps. Obtained objective quality measures, carried out on standard speech recordings, were compared to the state-of-the-art 3GPP-AMR speech coding system. REPORT motlicek:rr06-30/IDIAP Audio Coding Based on Long Temporal Contexts Motlicek, Petr Hermansky, Hynek Garudadri, Harinath Srinivasamurthy, Naveen EXTERNAL https://publications.idiap.ch/attachments/reports/2006/motlicek-idiap-rr-06-30.pdf PUBLIC Idiap-RR-30-2006 2006 IDIAP We describe novel audio coding technique designed to be utilized at medium bit-rates. Unlike classical state-of-the-art audio coders that are based on short-term spectra, our approach uses relatively long temporal segments of audio signal in critical-band-sized sub-bands. We apply auto-regressive model to approximate Hilbert envelopes in frequency sub-bands. Residual signals (Hilbert carriers) are demodulated and thresholding functions are applied in spectral domain. The Hilbert envelopes and carriers are quantized and transmitted to the decoder. Our experiments focused on designing audio coder to provide broadcast radio-like quality audio around $10-20$kbps. Objective quality measures indicate comparable performance with the 3GPP-AMR speech codec standard for both speech and non-speech signals.