I-Stream

Software based on different technologies

Technology	Bandwidth	Resolution	Frame Rate	Network	Cost
I-Stream	128kb-1Mb*1	768x576	25 fps(PAL),30fps(NTSC)	ISDN 128k ADSL 256k-8M DDN 2M VPN 1-2M	Medium
MPEG-4	128-512Kb	384x288	25 fps	ISDN 128Kb VPN 1-2Mb Dedicated network and LAN 10-100MB	Very expensive *2
H.323	128-512Kb	384x288	15 fps	ISDN DDN	Expensive
H.320	56-128Kb	176x144	15 fps	ISDN DDN	Expensive
H.263	56-64Kb	176x144	10 fps	ISDN DDN 56K modem	Low
MPEG	1.5Mb	384x288	25 fps	LAN 10-100Mb VCD	Medium
MPEG-2	10Mb	704x576	25 fps	Optical fibre connection LAN 100Mb DVD	Very High
MPEG-3	40Mb	1152x796	25 fps	Optical fibre connection HDTV	Very high

Note: *1. Resolution can be adjusted to suite different bandwidth.
*2. Real-time CODEC equipment for high resolution is very expensive.
CODEC TECHNOLOGIES COMPARISON

Technology	I-Stream	ITU	MPEG4	ITU
Video CODEC format	I-Stream	H.320/263	MPEG4	H.323/323+
Bandwidth	128Kb-1Mb	56-128Kb	128-512Kb	128-678Kb
Compression ratio (xxxx :1)	200-2000	10-100	200-500	100-250
Distortion	Low	High	Low	Average
Max Resolution	768x576	176x144	384x288	384x288
Colour (bit)	16	15	15	16
Frame rate (fps)	25	15	25	15
Audio CODEC	I-Stream	G7**	G7**	G7**
Bandwidth (Kb)	12.6	6-21	6-21	6-21
Audio quality	Telephone	Near Telephone	Telephone	Telephone
Format	I-Stream	PCM/GSM	PCM/GSM	PCM/GSM
Noise	Nil	Low	Nil	Nil
Delay (s)	< 0.2	<1.0	10-20	<1.0