Audio Coding
C.2.4 E.2.4 Dual Mono
Used if the left and right channels are carrying separate services. The encoder
knows that it must treat the two channels independently. The main use for this mode
is for multilingual transmission where decoder selects which language to decode on
left or right.
C.2.5 E.2.5 Surround Sound/5.1
A stereo signal produces a very focused audio field so unless the viewer is sitting in
the correct position, the audio reproduction suffers. More audio channels are
required to generate a larger audio field in which the viewer can listen.
The encoder expects the signal to arrive as:
• AES 0 - Left, right (coded as a stereo pair).
• AES 1 - Centre, Low Frequency Effect (coded as a mono channel with restricted
frequency on the LFE channel).
• AES 2 - Left surround, right surround.
C.2.6 E.2.6 Phase Aligned
Note: The feature “Phase Aligned Audio” is patent pending. An application for
patent has been filed in the Patent and Trademark Office.
This option is a proprietary feature of Ericsson Television, only available for MPEG1
Layer 2. It provides the capability of carrying 5.1 surround sound channels. This is
achieved by dual mono encoding of 3 pairs of audio channels.
In order to preserve the 5.1 surround image, phase alignment is critical, so audio
timing is much more tightly toleranced, with the audio timing between the surround
channels being sample accurate.
To Next Page
Loading...