Form Speex web-site comparion data

Codec Quality Comparison

Warning: these are machine-generated results (not from real listeners) and hence should be taken with a grain of salt.

Codec Feature Comparison

Codec	Rate (kHz)	bitrate (kbps)	delay frame+lookahead (ms)	multi-rate	embedded	VBR	PLC	bit-robust	license
Speex	8, 16, 32	2.15-24.6 (NB) 4-44.2 (WB)	20+10 (NB) 20+14 (WB)	yes	yes	yes	yes		open-source/ free software
iLBC	8	15.2 or 13.3	20+5 or 30+10				yes		no charge, but not open-source
AMR-NB	8	4.75-12.2	20+5?	yes			yes	yes	proprietary
AMR-WB (G.722.2)	16	6.6-23.85	20+5?	yes			yes	yes	proprietary
G.722.1 (Siren7)	16	(16) 24, 32	20+20	yes			yes	yes	no charge, but not open-source
G.729	8	8	10+5				yes	yes	proprietary
GSM-FR	8	13	20+?				?	?	patented?
GSM-EFR	8	12.2	20+?				yes	yes	proprietary
G.723.1	8	5.3 6.3	37.5				yes	?	proprietary
G.728	8	16	0.625						proprietary
G.722	16	48 56 64	?		yes			?	?

Definitions

multi-rate

Allows the codec to change bitrate dynamically, at any moment

embedded

A codec that embeds narrowband bitstreams in wideband bitstreams

VBR

Variable bitrate

PLC

Packet loss concealment

bit-robust

Robust to corruption at the bit level, as found on wireless networks

Special Features

Speex

Speex supports intensity stereo encoding and 32 kHz sampling

iLBC

iLBC frames are encoded completely independently; while this provides better quality when 10% (or more) of the packets are being dropped, this makes the codec suboptimal for clean line conditions.