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VoIP Vocoders

There are several considerations when evaluating a particular voice codec for an application. Each codec has a set of unique characteristics which may affect their suitability for a particular function and/or platform. VOCAL's embedded software libraries include a complete range of ETSI / ITU / IEEE compliant algorithms, in addition to many other standard and proprietary algorithms. Our software is optimized for execution on ANSI C and leading DSP architectures (TI, ADI, AMD, ARM, MIPS, CEVA, LSI Logic ZSP, etc.).

Current resource requirements for each platform are being updated. Please contact us directly for specific information. Reference MIPS/memory requirements for certain ADI 218x software libraries are available for comparison. Tables of many VoIP vocoders with their associated PSQM/PSQM+ values under various network conditions are also available.

Modules

The following C and optimized assembly embedded vocoder libraries are available, as source or object modules:

• iLBC
• MELP
• MELPe
• G.711
• G.722
• G.722.1
• G.722.2
• G.723.1
• G.726
• G.728
• G.729/G.729A
• G.729 Annex B
• Speex
• GSM speech codecs
• GSM 06.10 Full Rate
• GSM 06.20 Half Rate
• GSM 06.60 Enhanced Full Rate
• GSM 06.90 Adaptive Multi Rate

Applications

• WIFI phones VoWLAN
• Wireless GPRS EDGE systems
• Personal communications
• Wideband IP telephony
• Audio and video conferencing

Features

• Full and half duplex modes of operation
• Pass ITU test vectors
• Compliant with ITU specifications
• Optimized for high performance on leading edge DSP architectures
• Multichannel implementation
• Multi-tasking environment compatible

Configurations

• DAA interface using linear codec at 8.0 kHz sample rate
• Direct interface to 8.0 kHz PCM data stream (A-law or -law)
• North American/International Telephony (including caller ID) support available
• Simultaneous DTMF detector operation available - (less than 150 hits on Bellcore test tape typical)
• MF tone detectors, general purpose programmable tone detectors/generators available
• Data/Facsimile/Voice Distinction available
• Common compressed speech frame stream interface to support systems with multiple speech coders
• Dynamic speech coders selection if multiple speech codecs available
• Can be integrated with G.168 Echo Canceller and Tone Detection/Regeneration modules
• Complete facsimile systems available - modulations (V.34fax, V.17, et al.) and protocols (T.30) as a facsimile terminal or facsimile relay configuration
• Complete data modem systems available - modulations (V.90, V.34, et al.) and protocols (V.42, PPP framing, et al.)
• Various startup procedures available (V.8 and V.8bis)
• Multiple ports can be executed on a single DSP