ILBC
From Wikipedia, the free encyclopedia
- The correct title of this article is iLBC. The initial letter is shown capitalized due to technical restrictions.
The Internet Low Bit Rate Codec (iLBC) is a royalty free narrowband speech codec, developed by Global IP Sound (GIPS). It is suitable for VoIP applications, streaming audio, archival and messaging. The algorithm is a version of block-independent linear predictive coding, with the choice of data frame lengths of 20 and 30 milliseconds. The encoded blocks have to be encapsulated in a suitable protocol for transport, eg. RTP.
iLBC is defined in RFC 3951. It is one of the codecs used by the Gizmo Project, Ekiga, OpenWengo, Google Talk and Skype.
[edit] Parameters and features
- Sampling frequency 8 kHz/16 bit (160 samples for 20 ms frames, 240 samples for 30 ms frames)
- Controlled response to packet loss, delay and jitter
- Fixed bit rate (15.2 kbit/s for 20 ms frames, 13.33 kbit/s for 30 ms frames)
- Fixed frame size (304 bits per block for 20 ms frames, 400 bits per block for 30 ms frames)
- Robustness similar to PCM with packet loss concealment, like eg. the ITU-T G.711
- CPU load similar to G.729A, with higher basic quality and better response to packet loss
- Royalty free
[edit] External links
| Multimedia compression formats | ||||||
|---|---|---|---|---|---|---|
| Video compression formats | ISO/IEC | MPEG-1 | MPEG-2 | MPEG-4 | MPEG-4/AVC | ITU-T | H.261 | H.262 | H.263 | H.264 | Others | AVS | Dirac | Indeo | MJPEG | RealVideo | VC-1 | Theora | VP6 | VP7 | WMV |
| Audio compression formats | ISO/IEC MPEG | MPEG-1 Layer III (MP3) | MPEG-1 Layer II | AAC | HE-AAC | ITU-T | G.711 | G.722 | G.722.1 | G.722.2 | G.723 | G.723.1 | G.726 | G.728 | G.729 | G.729.1 | G.729a | Others | AC3 | ATRAC | FLAC | iLBC | Monkey's Audio | Musepack | RealAudio | SHN | Speex | Vorbis | WavPack | WMA |
| Image compression formats | ISO/IEC/ITU-T | JPEG | JPEG 2000 | JPEG-LS | JBIG | JBIG2 | -- | -- | Others | BMP | GIF | ILBM | PCX | PNG | TGA | TIFF | WMP |
| Media container formats | General | 3GP | ASF | AVI | FLV | Matroska | MP4 | MXF | NUT | Ogg | Ogg Media | QuickTime | RealMedia | Audio only | AIFF | AU | WAV | -- | -- |
