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  FlexCode Public Seminar, 16.12.2008,
Paris, Institut Telecom, Telecom ParisTech, CNRS LTCI
 
 

Title: FlexCode project - flexible source coder and some theoretical results on model-based quantization under high-rate theory assumptions
Speaker: Alexey Ozerov
Abstract:
In FlexCode project we are targeting to develop a new generation of flexible coders that are able to adapt in real time to continuously changing network conditions, and in particular to varying transmission rate. Most existing coders require rate-dependent off-line training and do not support such flexibility. We will present and discuss in details a practical coding scheme based on audio quantization with an adaptive quantizer derived from the autoregressive (AR) model under high-rate theory assumptions. The main advantage of this scheme compared to state-of-the-art training-based coders consists of its flexibility. The scheme can adapt in real time to any particular rate and has a computational complexity independent of the rate. Moreover, depending on the transmission channel flexibility, the scheme can easily switch between constant (constrained resolution quantization) and variable (constrained entropy quantization) transmission rates. We will also present some theoretical results on model-based quantization under high-rate theory assumptions that we have obtained recently. This part will include studies on
1. optimal rate distribution between signal and signal model,
2. optimal rate distribution between signal and model of perception,
3. optimal criteria for signal model estimation.
We will finish this talk by some conclusions and we will draw some promising research directions.

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