Martin Gartner

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This paper describes the scalable coder – G.729.1 – which has been recently standardized by ITU-T for wideband telephony and voice over IP (VoIP) applications. G.729.1 can operate at 12 different bit rates from 32 down to 8 kbit/s with wideband quality starting at 14kbit/s. This coder is a bitstream interoperable extension of ITU-T G.729 based on three(More)
—Recommendation G.729.1 is a new ITU-T standard which was approved in May 2006. This recommendation describes a hierarchical speech and audio coding algorithm built on top of a narrowband core codec. One challenge in the codec design is the generation of a wideband signal with a very limited additional bit rate (less than 2 kb/s). In this paper, we describe(More)
— We present an embedded and hierarchical 8–32 kbit/s speech and audio coding algorithm that has been successfully submitted to the ITU-T as a candidate [1] for ITU-T Rec. This contribution gives a comprehensive overview of the proposed codec, describes the implemented algorithms, and states a detailed characterization as well as results of the official(More)
Pre-echo is a well-known artefact of transform coding at low bit rates. In this paper we present a new method to address this problem. The input signal is assumed to be coded in two stages: in time domain first, and then in transform domain. This is for instance the case in CELP+transform embedded coding. The first stage reconstructs a signal that is(More)
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