Jan 19

OCS Audio Codecs

I’ve found some great tabels regarding audio codecs used and the bandwith they require. Note that MOS stands for mean opinion score, which is a subjective rating of sound quality
First the narrow band:

Narrowband VoIP codecs
Codec Payload bandwidth MOS Description
G.711 64 kbps 4.1 This is the most universally supported codec used in IP telephony.  This narrowband codec supports frequencies in the 300 to 3,400 hertz range and is uncompressed. Although the quality is very good, it consumes a lot of bandwidth.
G.729 8 kbps 3.92 This is the second most supported codec and offers nearly the same quality as G.711. The key advantage is that it is compressed eight times smaller than G.711 while sounding almost as good.

And second, wideband for a rich VoIP experience:

Wideband VoIP codecs
Codec Payload bandwidth Description
G.722 48 to 64 kbps This is the most common wideband codec available in IP phones, though wideband support is only recently gaining momentum. The quality is excellent at twice the sampling rate of standard G.711, but the compression isn’t that great. But considering the fact that it’s the same bit rate as narrowband G.711 but delivers much more realistic sound, G.722 will be one of the best codecs to use if your IP telephones will support it. Wideband supports frequencies of 50 to 7,000 hertz. There are no longer any patents covering G.722, so it’s free for anyone to use.
G.722.1 16 to 32 kbps This is a wideband codec, aka Siren7, developed by Polycom. Its key advantage is that it’s a computationally efficient and compact codec at 16 to 32 kbps, which is less than half the bandwidth required by G.722.  16 kbps mode isn’t appropriate for noisy audio input or if music is mixed in, since the compression artifacts are noticeable.  32 kbps is good for any kind of workload.  This codec must be licensed from Polycom, and it’s currently used only in Polycom’s high-end video conferencing systems under the marketing name “Ultimate HD.” Current Polycom IP phones use the marketing term “HD Voice,” which supports only generic G.722 for its wideband codec, although future IP phone models may support G.722.1.
G.722.2 6.6 to 23.85 kbps Also known as AMR-WB, this is a wideband codec. A 6.6 kbps mode is also supported, but 12.75 is the practical bit rate for speech in a clean environment. The higher 23.85 bit rate is better for noisy conditions and music. At the time of this writing, I’m not aware of any IP phones that support this codec. It’s currently used by T-Mobile in Germany for cell phone applications.
Speex wideband 10 to 28 kbps This is an excellent open source codec from Speex that offers very good wideband quality at relatively low bit rates. VBR (variable bit rate) is also supported in 12 or 18 kbps mode. This is a free open source codec and can be used by anyone. It’s supported by open source Asterisk PBX, but no hard IP phones and only one soft IP phone support it.
Siren14 ultra-wideband 24 to 32 kbps Siren14 is a free-to-license (not to be confused with license-free) ultra-wideband version of the G.722.1 codec from Polycom. Some of the high-end features in G.722.1, like echo cancellation and noise reduction, are omitted. Even though this is royalty free, you still need a license from Polycom. Siren14 supports a wider dynamic range up to 14,000 hertz, compared with 7,000 hertz in wideband.
Siren22 ultra-wideband 32 to 64 kbps Siren22 is a proprietary ultra-wideband codec from Polycom that currently can’t be licensed. Siren22 supports an even wider dynamic range–up to 22,000 hertz. The digital sampling rate is 48 KHz.

Enjoy the calculating for bandwith usage ;-)

Want to read more, here is my source: http://articles.techrepublic.com.com/5100-10878_11-6159446.html

Permanent link to this article: http://www.reijling.nl/?p=309


2 pings

Skip to comment form

  1. Good dispatch and this fill someone in on helped me alot in my college assignement. Thanks you on your information.

  2. Aloha, Dear blogger!
    I am Sophia from Holland and I am Analyst.
    You wrote a excellent piece, I am added it to my IE feed reader.
    piece of your thing interesting for my web-site readers.
    I want add your text to my web-site.
    Can i to do that, if I place a url to your skillful web-site ?
    I found your great piece via twitter ..
    Looks like your true blog have 5 millions surfers at your harismatic personal blog now, very good effect for every website maker.

    • Jeroen on 30/10/2010 at 20:15

    I think you are spamming.. but sure… you can post a link…

  3. This excellent article assited me very much! Saved your website, extremely excellent topics just about everywhere that I see here! I like the info, thanks.

  4. Thanks very much for writing all of the good content! I am looking forward to checking out more blogs!

  5. Keep posting stuff like this i really like it

  6. Great piece of details that you’ve obtained on this website submit. Hope I might get some a lot more of the stuff in your website. I will are available back again.

  7. Hi, It’s hard to find knowledgeable people on this topic, but you sound like you know what you’re talking about! Thanks

  8. Great Share! This is the right blog for anyone who wants to find out about this topic. You realize so much its almost hard to argue with you (not that I actually would want…HaHa). You definitely put a new spin on a topic thats been written about for years. Great stuff, just great!

  9. Wow!! Again you look good!!dude,and always have the wonderful tips!! found another article on the same sort of thing.

  1. […] Dit blogartikel was vermeld op Twitter door Open Voice PBX, VoIP Hub. VoIP Hub heeft gezegd: OCS Audio Codecs | Jeroen Reijling Blog http://bit.ly/840DtE […]

  2. […] Narrowband VoIP codecs. Codec, Payload bandwidth, MOS, Description. G.711, 64 kbps, 4.1, This is the most universally supported codec used in IP telephony. This narrowband codec supports frequencies in the 300 to 3400 hertz range and is … It’s supported by open source Asterisk PBX, but no hard IP phones and only one soft IP phone support it. Siren14 ultra-wideband, 24 to 32 kbps, Siren14 is a free-to-license (not to be confused with license-free) ultra-wideband version …Continue Reading… […]

Leave a Reply

Your email address will not be published.