1.2 Kbit/s Harmonic Coder Using Auditory Filters
نویسنده
چکیده
In this paper, a very low bit speech coder at 1.2 kbps is newly proposed. Like the LPC vocoder, it only requires gain, pitch, and spectral information, but its quality is far superior. The synthesis method is one of harmonic coding, using sinusoids whose frequencies are multiples of the fundamental frequency, where the amplitudes of the sinusoids are adaptively modulated using Gammatone lters as a perceptual weighting lter. The sinusoids' phases are also adjusted so as to maximize the perceptual quality. In order to reduce the total bit rate to 1.2 kbit/s, a new segment coder for spectral information (LSP coe cients) using DP matching is also proposed. The quality of the synthesized speech was improved by 0.45 in the Mean Opinion Score (MOS) compared with that of the simple LPC vocoder operating at the same rate, and it was comparable to that of 2.4kbit/s MELP coder.
منابع مشابه
An 8-32 kbit/s scalable wideband coder extended with MDCT-based bandwidth extension on top of a 6.8 kbit/s narrowband CELP coder
In this paper, we present a 6.8-32 kbit/s scalable speech and audio coder using a modified-discrete-cosine-transform (MDCT)-based bandwidth extension on top of a 6.8 kbit/s code-excited-linear-prediction (CELP) coder. The proposed coder comprises a 6.8 kbit/s narrowband CELP as its corelayer and eight enhancement layers with the bitrates of 0.8, 1.2, 3.2, or 4.0 kbit/s. After encoding of a narr...
متن کاملcentre for digital music Low Bitrate Object Coding of Musical Audio Using Bayesian Harmonic Models
This article deals with the decomposition of music signals into pitched sound objects made of harmonic sinusoidal partials for very low bitrate coding purposes. After a brief review of existing methods, we recast this problem in the Bayesian framework. We propose a family of probabilistic signal models combining learnt object priors and various perceptually motivated distortion measures. We des...
متن کاملA sinusoidal harmonic vocoder at 1.2 kbps using auditory perceptual characteristics
In this paper, a very low bit speech coder at 1.2 kbps is newly proposed. Like the LPC vocoder, it requires few types of information (power, pitch, and spectral information), but its quality is far superior. In the proposed vocoder, the synthesized speech quality is improved based on auditory perceptual characteristics. lbe synthesis method is one of harmonic coding, using sinusoids whose frequ...
متن کاملA 4 kbit/s renewal code excited linear prediction speech coder
This paper proposes a new 4 kbit/s speech coder based on CELP structure with 45 ms total codec delay. The coder is mainly featured by the renewal codebook of the excitation signal and the linked split-vector quantizer of LSPs which enable the coder to get high quality speech at low bit rate. In addition, techniques of the formant enhancement in spectral envelop and the harmonic recovery in tran...
متن کاملA wideband CELP speech coder at 16 kbit/s based on mel-generalized cepstral analysis
This paper proposes a wideband CELP coder using frequency warping. Instead of linear prediction, the proposed coder adopts the melgeneralized cepstral analysis, and encodes fullband of the speech signal through a warped frequency scale. It is shown that the subjective quality of the proposed coder at 16 kbit/s is better than that of the ITU-T G.722 at 64 kbit/s. Furthermore, the proposed coder ...
متن کامل