G.711.1
CODEC OVERVIEW
G.711.1 speech codec was standardized by ITU-T in 2008. The codec operates on each 5 ms frame of 16-bit speech/audio signals sampled at 8 KHz or 16 KHz and generates a compressed bit-stream having bit-rates of 64 kbps, 80 kbps, or 96 kbps structured as 3 layers. The layered approach allows the decoder or any other component in the communication system to truncate the bit-stream by removing the higher layers. The base layer (Layer 0), at 64 kbps, is inter-operable with the traditional G.711. Layer 1 provides a lower band enhancement bit-stream at 16 kbps. Layer 2 provides a higher band enhancement bit-stream for the 16 KHz sampling frequency at 16 kbps. To improve the quality under frame erasures due to channel errors such as packet-losses, frame erasure concealment algorithms are provided at the decoder. This codec aims to achieve high-quality speech services over broadband networks, particularly for IP phone and multi-point speech conferencing, while enabling a seamless interoperability with conventional terminals and systems equipped only with G.711.
SALIENT FEATURES
- Based on ITU-T specification.
- Optimized ASM/C implementation.
- Re-entrant implementation.
- C-callable APIs.
- Operates on speech/audio signals sampled at 16 KHz and 8 KHz.
- Support for 64 kbps and 80 kbps bit-rate for the 8 KHz sampling frequency.
- Support for 64 kbps, 80 kbps, and 96kbps bit-rate for the 16 KHz sampling frequency.
- Support for RTP payload format as specified in RFC 3551.
- Support for the integrated frame erasure concealment algorithm.
- Support for the RTP payload format as specified in the standard.
- Optional support for xDM APIs on TI platforms.
TESTING FEATURES
- Tested for bit-exactness with standard as well as a large database of non-standard test vectors.
- Module is fully interruptible.
- Tested for compliance with register preservation requirements.
- Tested for Input buffer corruption.
- Tested for I/O buffer alignment requirements.
- Tested for multi-instance implementation.
- Tested for 100% code coverage.
- Range validation for all the API parameters.
- Tested with scratch contamination at frame boundaries.
- Tested for packet loss conditions with 5% loss to 25% loss.
- TI C55x implementation validated on Spectrum Digital C5510 DSK.