Yamaha YRS-2100 Owner's Manua page 30

Playback features
y
1)
If the input signal includes channels that cannot be displayed in the
format shown in the display example, the total number of channels will
be displayed, as in "5.1ch".
28
En
■ Displaying the input signal information
(Signal Info)
Press / key to change the following information.
Format Digital audio format
Channel The number of channels included in input signal
(front/surround/LFE (low frequency sound
effects))
Display example: [3/2/0.1]
Surround 2ch, LFE for input signal
Sampling Sampling frequency for digital input signal
Bitrate Bitrate per second of input signal
HDMI In HDMI video signal resolution
HDMI Message When error occurs with HDMI (displayed only
when error is occurred.)
Front 3ch,
1)