Adaptive Multi-Rate audio codec

About: Adaptive Multi-Rate audio codec is a research topic. Over the lifetime, 1467 publications have been published within this topic receiving 19736 citations. The topic is also known as: AMR & Adaptive Multi-Rate.

Video codec, for a videophone terminal of an integrated services digital network

Abstract: A video codec for a videophone terminal of an integrated services digital network. The codec is organized to receive firstly image signals from a television camera so as to transmit them, after compressing and encoding them, to a remote video decoding unit, via a digital transmission line, and secondly similarly-processed image signals via the digital transmission line, so as to decompress and decode them for a television screen receiver locally connected to the video codec. The video codec includes a processing unit, of the integrated circuit type, co-operating with a single external memory plane both to compress and encode data to be transmitted, and also to decompress and decode received data, with the assistance of internal operational components time shared so as to apply known methods to transmission and to reception.

On the architecture of the cdma2000/spl reg/ variable-rate multimode wideband (VMR-WB) speech coding standard

Abstract: The description and design of the source-controlled variable-rate multimode wideband (VMR-WB) codec recently selected by the 3/sup rd/ Generation Partnership Project 2 (3GPP2) for the cdma2000/spl reg/ system in Rate-Set II are presented. The paper gives an overview of the codec and the methodologies that enable high quality wideband coding at average data rates ranging from TIA/EIA/IS-733 ADR (average data rate) to that of TIA/EIA/IS-127. The codec has three modes of operation at different average data rates and a fourth mode that is interoperable with 3GPP/AMR-WB (ITU-T G.722.2). Despite the interoperability constraint, the codec is capable of meeting the aggressive performance requirements through the use of novel techniques such as noise suppression, efficient signal classification, new coding types optimized for stable voiced and unvoiced frames, novel post-processing technique for periodicity enhancement in the lower frequency band, and improved frame erasure concealment mechanisms.

Single and double frame coding of speech LPC parameters using a lattice-based quantization scheme

Abstract: A lattice-based scheme for the single-frame and the double-frame quantization of the speech line spectral frequency parameters is proposed. The lattice structure provides a low-complexity vector quantization framework, which is implemented using a trellis structure. In the single-frame scheme, the intraframe dependencies are exploited using a linear predictor. In the double-frame scheme, the parameters of two consecutive frames are jointly quantized and hence the interframe dependencies are also exploited. A switched scheme is also considered in which, lattice-based double-frame and single-frame quantization is performed for each two frame and the one which results in a lower distortion is chosen. Comparisons to the Split-VQ, the Multi-Stage VQ, the Trellis Coded Quantization, the interframe Block-Based Trellis Quantizer, and the interframe scheme used in IS-641 EFRC and the GSM AMR codec are provided. These results demonstrate the effectiveness of the proposed lattice-based quantization schemes, while maintaining a very low complexity. Finally, the issue of the robustness to channel errors is investigated

Video transmission apparatus

Abstract: A video transmission apparatus comprises video codec for compression-encoding video data to be transmitted and decompression-decoding video data as received; a first audio codec for compression-encoding first audio data to be transmitted and decompression-decoding first audio data as received; a second audio codec for compression-encoding second audio data to be transmitted and decompression-decoding second audio data as received; a multiplexer-demultiplexer for including a three-channel buffer memory and processor; and an interface connectable to communications satellite network and ground network. In the multiplexer-demultiplexer, video data-first audio data and second audio data to be transmitted are multiplexed and converted to a packet based on a predetermined communication format, and packet as received is separated into video data-first audio data, and second audio data.

Single-Chip MPEG-2 422P@HL CODEC LSI with Multi-Chip Configuration for Large Scale Processing beyond HDTV Level

Abstract: This paper proposes a new architecture for VASA, a single-chip MPEG-2 422P@HL CODEC LSI with multichip configuration for large scale processing beyond the HDTV level, and demonstrates its flexibility and usefulness. This architecture consists of triple encoding cores, a decoding core, a multiplexer/de-multiplexer core, and several dedicated application-specific hardware modules with a hierarchical flexible communication scheme for high-performance data transfer. VASA is the world's first single-chip full-specs MPEG-2 422P@HL CODEC LSI with a multi-chip configuration. The VASA implements MPEG-2 video and system CODEC with generic audio CODEC interfaces. An LSI incorporating the architecture was successfully fabricated using the 0.13 /spl mu/m eight-metal CMOS process. The architecture not only provides an MPEG-2 422P@HL CODEC but also large scale processing beyond the HDTV level for digital cinema and multi-view/-angled live TV applications with a multi-chip configuration. The VASA implementations will lead to a new dimension in future high-quality, high-resolution digital multimedia entertainment.