Method for interoperation between adaptive multi-rate wideband (AMR-WB) and multi-mode variable bit-rate wideband (VMR-WB) codecs

• US 20050267746A1
• Filed: 01/19/2005
• Published: 12/01/2005
• Est. Priority Date: 10/11/2002
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Salami, Redwan, Jelinek, Milan
• Granted Patent: US 7,203,638 B2
• Time in Patent Office: Days
• US Class Current: 704/226
• CPC Class Codes: G10L 19/012 Comfort noise or silence coding
• CPC Class Codes: G10L 19/173 Transcoding, i.e. converting between two coded representations avoiding cascaded coding-decoding
• CPC Class Codes: G10L 19/24 Variable rate codecs, e.g. for generating different qualities using a scalable representation such as hierarchical encoding or layered encoding

Abstract

A source-controlled Variable bit-rate Multi-mode WideBand (VMR-WB) codec, having a mode of operation that is interoperable with the Adaptive Multi-Rate wideband (AMR-WB) codec, the codec comprising: at least one Interoperable full-rate (I-FR) mode, having a first bit allocation structure based on one of a AMR-WB codec coding types; and at least one comfort noise generator (CNG) coding type for encoding inactive speech frame having a second bit allocation structure based on AMR-WB SID_UPDATE coding type. Methods for i) digitally encoding a sound using a source-controlled Variable bit rate multi-mode wideband (VMR-WB) codec for interoperation with an adaptative multi-rate wideband (AMR-WB) codec, ii) translating a Variable bit rate multi-mode wideband (VMR-WB) codecsignal frame into an Adaptive Multi-Rate wideband (AMR-WB) signal frame, iii) translating an Adaptive Multi-Rate wideband (AMR-WB) signal frame into a Variable bit rate multi-mode wideband (VMR-WB) signal frame, and iv) translating an Adaptive Multi-Rate wideband (AMR-WB) signal frame into a Variable bit rate multi-mode wideband (VMR-WB) signal frame are also provided.

Claims

1. An interworking function, comprising a unit operable with a source-controlled Variable bit-rate Multi-mode WideBand (VMR-WB) codec providing a mode of operation that is interoperable with an Adaptive Multi-Rate wideband (AMR-WB) codec, where in a VMR-WB encoding/AMR-WB decoding case, speech frames are encoded in an AMR-WB interoperable mode of a VMR-WB encoder using one of bit rates corresponding to Interoperable-Full Rate (I-FR) for active speech frames, Interoperable-Half Rate (I-HR) at least for dim-and-burst signaling, Quarter Rate-Comfort Noise Generator (CNG-QR) to encode at least relevant background noise frames and Eighth Rate-Comfort Noise Generator (CNG-ER) frames for background noise frames not encoded as CNG-QR frames, said interworking function operable such that,

invalid frames are transmitted to an AMR-WB decoder as erased frames;

I-FR frames are transmitted to the AMR-WB decoder as 12.65, 8.85 or 6.60 kbps AMR-WB frames depending on the I-FR type;

CNG-QR frames are transmitted to the AMR-WB decoder as Silence Descriptor Update (SID_UPDATE) frames;

CNG-ER frames are transmitted to the AMR-WB decoder as NO_DATA frames; and

I-HR frames are translated to 12.65, 8.85, or 6.60 kbps frames, depending on the frame type, by generating missing algebraic codebook indices, where bits indicating the I-HR type are discarded.