- platforms:
- Sun SPARCstation
- Silicon Graphics 4D/30 and 4D/35 (Indigo) and Indy
- audio protocols:
- vat audio packet format
- real-time transport protocol (RTP), RFC 1889 and RFC 1890
- transport protocols:
- unicast UDP
- multicast UDP
- operation as gateway or end system
- compatible with vat session protocol
- Tk user interface
- control through Tcl language:
- initialization file
- command line arguments
- interactive
- several independent concurrent conferences, each with different
encoding and compression
- DES-based voice encryption
- current audio encodings supported:
- 16 bit linear encoding, with all hardware-supported sample
rates (SPARCstation 10 and SGI)
- 64 kb/s mu-law PCM (CCITT G.711)
- 32 kb/s ADPCM (CCITT G.721) (SPARCstation)
- 32 kb/s Intel/DVI ADPCM
- 24 kb/s ADPCM (CCITT G.723) (SPARCstation)
- 13 kb/s GSM 06.10
- 4.8 kb/s LPC (linear-predictive coding) with setable vocoder
interval
- mono or stereo
- mike-mutes-net or net-mutes-mike modes
- each site can use different audio encodings
- playback and recording of audio files (.au and AIFF/AIFC formats),
with encoding translation
- arbitrary voice packet length, which may differ for each site
- lost packet substitution
- setable audio buffer occupancy
- configurable adjustment mechanisms for playout delay, VU meter,
silence detector and automatic gain control
- redefinable session identifier string with variable substitution
- on-line statistics with selectable graphing