Tieline Bridge-IT, Руководство пользователя

Страница: 171 / 227

171
© Tieline Research Pty. Ltd. 2019
Bridge-IT Manual v4.0
17.5 Selecting an Algorithm
The codec offers a range of high quality algorithm options as well as 16 Bit 22kHz linear PCM
audio at less than 12 ms encode delay for high quality, uncompressed audio.
All Bridge-IT and Bridge-IT XTRA codecs include Opus, MPEG Layer 2, G.711 and G.722
algorithms, as well as the AAC suite of algorithms and Tieline Music and MusicPLUS as standard.
Music and Music PLUS are optimized for wired and wireless IP connections.
aptX® Enhanced is included in Bridge-IT XTRA and can be purchased separately as a license
upgrade in Bridge-IT codecs.
Bridge-IT Algorithm Encode License Options Bridge-IT Bridge-IT XTRA
AAC-LD, AAC-ELD, LC-AAC, HE-AAC v.1 and HE-AAC v.2
algorithms
16 bit and 24 bit aptX® Enhanced algorithm
*
Included
* Option available for purchase separately if required.
Note: Bridge-IT has a range of default connection profiles that make it very simple to easily
program your codec to connect using all available algorithms. See
Choosing Dialing Profiles for
more details.
Overview of Tieline Algorithms
1. The Tieline Music algorithm is optimized for audio bit rates as low as 19.2kbps with only a 20
millisecond encode delay. It offers 15 kHz mono from 24Kbps to 48Kbps.
2. Tieline MusicPLUS delivers up to 20 kHz mono from 48kbps upwards. It can also deliver up to
20 kHz stereo from 96kbps upwards, offering huge savings on your IP data bills and
outstanding audio quality.
Overview of AAC Algorithms
Important Notes: AAC algorithms are only available in Bridge-IT if the AAC license has
been purchased and uploaded into the Bridge-IT codec. For more information see
Installing Software Licenses .
AAC-LC
LC-AAC is optimised for audio bit-rates of 64Kbps per channel or higher using a sample rate
of 48kHz. Tieline recommends using LC-AAC instead of HE-AAC if bandwidth of 64Kbps or
higher per channel is available, to optimise audio quality. If lower than 64Kbps is available,
consider using HE-AAC, Tieline Music or Tieline MusicPLUS.
AAC-HE
Codecs include both HE-AAC v.1 and HE-AAC v.2, which are optimized for low bit rate
connections. Selection of HE-AAC v.1 and v.2 is automatically managed within the codec, so
only
AAC-HE is displayed on the screen. When used for mono connections, HE-AAC v.1
performs best at bit rates of 24kbps per channel or higher. HE-AAC v.1 is also used for stereo
connections when audio connection bandwidth is 48kbps or higher.
HE-AAC v.2 is used for stereo connections when audio connection bandwidth is below 48kbps
and is capable of delivering 15kHz quality stereo audio at audio bit rates as low as 24kbps.
A sample rate of 32kHz is used in the codec's default profiles to achieve ultra-low bit-rate
connections, but this is adjustable to 44.1kHz or 48kHz if required.