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--- products:sbc:vim3:applications:earc [2023/11/08 21:11]
nick
+++ products:sbc:vim3:applications:earc [2025/05/19 21:40] (current)
reeve
@@ Line 3: / Line 3: @@
 ===== Introduction =====
-The eARC is a feature implemented in the latest HDMI 2.1 specification, the biggest advantage is that it exceedingly improves bandwidth and speed. \\
+eARC is a feature implemented in the latest HDMI 2.1 specification, This allows you to transmit high-quality audio from your TV to your Soundbar or AV receiver and is compatible with the high bitrate formats Dolby Atmos and DTS.
-This allows you to transmit high-quality audio from your TV to your Soundbar or AV receiver and is compatible with the high bitrate formats Dolby Atmos and DTS.
-This documentation will guide you how to recored audio from eARC.
+This documentation will guide you how to record audio from the HDMI eARC channel.
 <WRAP important >
@@ Line 15: / Line 14: @@
 ===== TV side setup =====
-In order to use the ''eARC'' functuion, you need to make sure your TV supports the ''eARC'' function, in generic, if the HDMI slot on your TV has a ''eARC'' mark,\\
+In order to use the eARC function, you need to make sure your TV is also eARC capable, It is denoted by the eARC label on the HDMI Input.
-it means your TV supports eARC function, anyway you need to check with your TV vendor whether it supports or not.
-You also need to enable the ''eARC'' function on your TV if it supports, you can check with the TV vendor about how to enable it.
+You can also check with the TV vendor about how to enable it.
 ===== VIM3L side setup =====
-You also need to enable the 'eARC' RX function on VIM3L, you can follow the command below to enable 'eARC' RX.
+You also need to enable the eARC Receiver function on VIM3L, you can follow the command below to enable eARC RX.
 ```shell
-amixer cset name='ARC eARC RX enable' 1
+$ amixer -c 0 cset name='ARC eARC RX enable' 1
 ```
+Check its status if it's enabled:
+```shell
+$ amixer -c 0 cget name='ARC eARC RX enable'
+numid=41,iface=MIXER,name='ARC eARC RX enable'
+  ; type=BOOLEAN,access=rw------,values=1
+  : values=on
+```
+''values=on'' means eARC RX is enabled.
+===== Hardware connection =====
+You need to use a HDMI 2.1 cable to connect VIM3L HDMI port to your TV HDMI Input with eARC function.
+===== Check eARC status =====
 You can follow the command below to check the status of eARC.
 ```shell
-khadas@Khadas:~$ amixer cget name='eARC_RX attended type'
+khadas@Khadas:~$ amixer -c 0 cget name='eARC_RX attended type'
 numid=24,iface=MIXER,name='eARC_RX attended type'
   ; type=ENUMERATED,access=rw------,values=1,items=3
@@ Line 40: / Line 55: @@
 ```
+^ Value ^ Status ^
+|''values=2''| Device work on eARC |
+|''values=1''| Device work on ARC |
+|''values=0''| ARC/eARC not connected |
+If your setup is correct, it should be ''values=2'' which means work on eARC.
+<WRAP tip >
+You can also try to unplug/replug HDMI cable to check.
+</WRAP>
+===== Record audio from eARC =====
+You can check the record sound devices with ''arecord -l''
+```shell
+$ arecord -l
+**** List of CAPTURE Hardware Devices ****
+card 0: AMLAUGESOUND [AML-AUGESOUND], device 0: TDM-B-dummy-alsaPORT-i2s multicodec-0 []
+  Subdevices: 1/1
+  Subdevice #0: subdevice #0
+card 0: AMLAUGESOUND [AML-AUGESOUND], device 1: TDM-A-dummy-alsaPORT-pcm multicodec-1 []
+  Subdevices: 1/1
+  Subdevice #0: subdevice #0
+card 0: AMLAUGESOUND [AML-AUGESOUND], device 2: TDM-C-dummy dummy-2 []
+  Subdevices: 1/1
+  Subdevice #0: subdevice #0
+card 0: AMLAUGESOUND [AML-AUGESOUND], device 3: PDM-dummy-alsaPORT-pdm dummy-3 []
+  Subdevices: 1/1
+  Subdevice #0: subdevice #0
+card 0: AMLAUGESOUND [AML-AUGESOUND], device 4: SPDIF-dummy-alsaPORT-spdif dummy-4 []
+  Subdevices: 1/1
+  Subdevice #0: subdevice #0
+card 0: AMLAUGESOUND [AML-AUGESOUND], device 6: EARC/ARC-dummy-alsaPORT-earc dummy-6 []
+  Subdevices: 1/1
+  Subdevice #0: subdevice #0
+card 0: AMLAUGESOUND [AML-AUGESOUND], device 7: LOOPBACK-A-dummy-alsaPORT-loopback dummy-7 []
+  Subdevices: 1/1
+  Subdevice #0: subdevice #0
+```
+The ''card 0, device 6'' device is the eARC device. You can record audio with the command below:
+```shell
+arecord -D hw:0,6 -f S16_LE -c 2 -r 48000 /tmp/out.wav
+```

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