Which codecs should I choose for devices
From KolmiSoft Wiki
It depends.
Contents |
[edit] What codecs are supported?
Audio:
- G.711 A-law
- G.711 u-law
- G.723.1
- G.726
- G.729
- GSM
- iLBC
- LPC10
- Speex
- ADPCM
- 16 bit Signed Linear PCM
Video:
- H.261
- H.263
- H.263+
- H.264
[edit] Audio codecs
Most commonly used are:
- G711
- G729
[edit] G711
PSTN quality codec which is supported in 99% of all devices/providers (but often disabled to save traffic).
It has best quality but highest bandwidth (64kbps + ~20 kbps overhead ~= 84kbps to one direction).
It comes in 2 flavours - G711u (ulaw) - used in USA, and G711a (alaw) - used mostly in Europe and other countries.
[edit] G729
Little worse quality but is often used because it saves traffic (~8kbps + ~20kbps overhead ~= 28kbps to one direction).
It needs to be installed separately and it is not free.
[edit] Video
Read manual for your device to check which codec is supported on your device.
H263/H264 are most popular.
Make sure same codec is chosen between devices you are trying to communicate.
[edit] Fax
If your system/provider/devices does not support T38 you should use G711 codec for fax transmitting/receiving.
[edit] Notes
Make sure you have always selected audio codec! Otherwise you will not be able to place calls!
