PhD Defense: "Advances in audio coding and networking by effective exploitation of long term correlations"

Tejaswi Nanjundaswamy

March 22nd (Friday), 1:30pm
Engineering Science Building (ESB), Rm 2003

A wide range of multimedia applications such as internet radio and television, online media streaming, gaming, and high fidelity teleconferencing heavily rely on efficient transmission of audio signals over networks. The two main challenges for such transmission is delay constrained compression, and dealing with loss of content due to noisy channels. Constraints on delay means that the algorithms can only operate on small block sizes (or frame lengths). Thus the key to addressing these challenges is efficiently exploiting inter-frame redundancies due to long term correlations. While well known audio coders are effective in eliminating redundancies within a block of data, and the only known inter-frame redundancy removal technique of employing a long term prediction (LTP) filter is too simplistic, as it is suboptimal for the commonly occurring polyphonic audio signals, which contain a mixture of several periodic components, and also suboptimal for speech and vocal content, which is quasi-periodic with small variations in pitch period. Moreover the typically employed parameter estimation technique is mismatched to the ultimate perceptual distortion criteria of audio coding. Similarly even in loss concealment, none of the existing techniques are designed to overcome the main challenge due to the polyphonic nature of most music signals. This talk covers our contributions towards addressing all these shortcomings by employing novel sophisticated filter structures suitable for a wide variety of audio signals, with parameter estimation which takes into account the perceptual distortion criteria for audio compression, and utilizes all the available information for loss concealment.

About Tejaswi Nanjundaswamy:

photo of Tejaswi Nanjundaswamy Tejaswi Nanjundaswamy received his B.E degree in electronics and communications engineering from the National Institute of Technology Karnataka, India, in 2004, the M.S. degree in electrical and computer engineering from UCSB, in 2009 and is currently pursuing PhD. under the guidance of Prof. Kenneth Rose at the Signal Compression Lab. He worked at Ittiam Systems, Bangalore, India from 2004 to 2008 as Senior Engineer in the Audio group. He also interned in the Multimedia Codecs division of Texas Instruments (TI) in 2003. His research interests include audio and speech processing/coding. He won the Student Technical Paper Award at the Audio Engineering Society's 129th Convention. He was also a Best Paper Award Finalist at IEEE Workshop on Applications of Signal Processing to Audio and Acoustics (WASPAA). t.nanjundaswamy.jpg

Hosted by: Professor Kenneth Rose