I2S audio output
Posted: Mon Oct 04, 2021 9:39 pm
Hello,
I've bought some small I2S audio amplifiers to play music on speakers. They work fine on a Raspberry Pi 3B+, following a tutorial from Adafruit. Then I tried to use them on a NanoPi NEO that has dedicated I2S pins. My first effort was with Armbian but that doesn't have any support for I2S so I looked for other options. I found the "official" OS image on the FriendlyElec wiki page and downloaded and installed nanopi-neo_sd_friendlycore-focal_4.14_armhf_20210618.img onto the SD card. It should be based on Ubuntu 20.04, the kernel is "Linux NanoPi-NEO 4.14.111 #193 SMP Thu Jun 10 18:20:47 CST 2021 armv7l armv7l armv7l GNU/Linux".
At least alsamixer shows some output and even input channels, one of them is named DAC. There are even multiple sound cards, one of them has "hdmi" in the name. I think I've tried all of them with speaker-test but couldn't hear anything.
What are the correct settings to make the I2S output work with common audio playback software like mpg123 or speaker-test?
I did a web search but found nothing. This forum doesn't want to search because it thinks that "i2s" is a too common term. So if it's so common here, I guess somebody should be able to tell me how it works.
Here's the output of 'aplay -l':
And the output of 'aplay -L':
I've bought some small I2S audio amplifiers to play music on speakers. They work fine on a Raspberry Pi 3B+, following a tutorial from Adafruit. Then I tried to use them on a NanoPi NEO that has dedicated I2S pins. My first effort was with Armbian but that doesn't have any support for I2S so I looked for other options. I found the "official" OS image on the FriendlyElec wiki page and downloaded and installed nanopi-neo_sd_friendlycore-focal_4.14_armhf_20210618.img onto the SD card. It should be based on Ubuntu 20.04, the kernel is "Linux NanoPi-NEO 4.14.111 #193 SMP Thu Jun 10 18:20:47 CST 2021 armv7l armv7l armv7l GNU/Linux".
At least alsamixer shows some output and even input channels, one of them is named DAC. There are even multiple sound cards, one of them has "hdmi" in the name. I think I've tried all of them with speaker-test but couldn't hear anything.
What are the correct settings to make the I2S output work with common audio playback software like mpg123 or speaker-test?
I did a web search but found nothing. This forum doesn't want to search because it thinks that "i2s" is a too common term. So if it's so common here, I guess somebody should be able to tell me how it works.
Here's the output of 'aplay -l':
Code: Select all
**** List of PLAYBACK Hardware Devices ****
card 0: Dummy [Dummy], device 0: Dummy PCM [Dummy PCM]
Subdevices: 8/8
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
Subdevice #2: subdevice #2
Subdevice #3: subdevice #3
Subdevice #4: subdevice #4
Subdevice #5: subdevice #5
Subdevice #6: subdevice #6
Subdevice #7: subdevice #7
card 1: Loopback [Loopback], device 0: Loopback PCM [Loopback PCM]
Subdevices: 8/8
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
Subdevice #2: subdevice #2
Subdevice #3: subdevice #3
Subdevice #4: subdevice #4
Subdevice #5: subdevice #5
Subdevice #6: subdevice #6
Subdevice #7: subdevice #7
card 1: Loopback [Loopback], device 1: Loopback PCM [Loopback PCM]
Subdevices: 8/8
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
Subdevice #2: subdevice #2
Subdevice #3: subdevice #3
Subdevice #4: subdevice #4
Subdevice #5: subdevice #5
Subdevice #6: subdevice #6
Subdevice #7: subdevice #7
card 2: Codec [H3 Audio Codec], device 0: CDC PCM Codec-0 []
Subdevices: 1/1
Subdevice #0: subdevice #0
card 3: allwinnerhdmi [allwinner,hdmi], device 0: 1c22800.i2s-i2s-hifi i2s-hifi-0 []
Subdevices: 1/1
Subdevice #0: subdevice #0
And the output of 'aplay -L':
Code: Select all
null
Discard all samples (playback) or generate zero samples (capture)
sysdefault:CARD=Dummy
Dummy, Dummy PCM
Default Audio Device
dmix:CARD=Dummy,DEV=0
Dummy, Dummy PCM
Direct sample mixing device
dsnoop:CARD=Dummy,DEV=0
Dummy, Dummy PCM
Direct sample snooping device
hw:CARD=Dummy,DEV=0
Dummy, Dummy PCM
Direct hardware device without any conversions
plughw:CARD=Dummy,DEV=0
Dummy, Dummy PCM
Hardware device with all software conversions
sysdefault:CARD=Loopback
Loopback, Loopback PCM
Default Audio Device
front:CARD=Loopback,DEV=0
Loopback, Loopback PCM
Front speakers
surround21:CARD=Loopback,DEV=0
Loopback, Loopback PCM
2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=Loopback,DEV=0
Loopback, Loopback PCM
4.0 Surround output to Front and Rear speakers
surround41:CARD=Loopback,DEV=0
Loopback, Loopback PCM
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=Loopback,DEV=0
Loopback, Loopback PCM
5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=Loopback,DEV=0
Loopback, Loopback PCM
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=Loopback,DEV=0
Loopback, Loopback PCM
7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
dmix:CARD=Loopback,DEV=0
Loopback, Loopback PCM
Direct sample mixing device
dmix:CARD=Loopback,DEV=1
Loopback, Loopback PCM
Direct sample mixing device
dsnoop:CARD=Loopback,DEV=0
Loopback, Loopback PCM
Direct sample snooping device
dsnoop:CARD=Loopback,DEV=1
Loopback, Loopback PCM
Direct sample snooping device
hw:CARD=Loopback,DEV=0
Loopback, Loopback PCM
Direct hardware device without any conversions
hw:CARD=Loopback,DEV=1
Loopback, Loopback PCM
Direct hardware device without any conversions
plughw:CARD=Loopback,DEV=0
Loopback, Loopback PCM
Hardware device with all software conversions
plughw:CARD=Loopback,DEV=1
Loopback, Loopback PCM
Hardware device with all software conversions
sysdefault:CARD=Codec
H3 Audio Codec,
Default Audio Device
dmix:CARD=Codec,DEV=0
H3 Audio Codec,
Direct sample mixing device
dsnoop:CARD=Codec,DEV=0
H3 Audio Codec,
Direct sample snooping device
hw:CARD=Codec,DEV=0
H3 Audio Codec,
Direct hardware device without any conversions
plughw:CARD=Codec,DEV=0
H3 Audio Codec,
Hardware device with all software conversions
sysdefault:CARD=allwinnerhdmi
allwinner,hdmi,
Default Audio Device
dmix:CARD=allwinnerhdmi,DEV=0
allwinner,hdmi,
Direct sample mixing device
dsnoop:CARD=allwinnerhdmi,DEV=0
allwinner,hdmi,
Direct sample snooping device
hw:CARD=allwinnerhdmi,DEV=0
allwinner,hdmi,
Direct hardware device without any conversions
plughw:CARD=allwinnerhdmi,DEV=0
allwinner,hdmi,
Hardware device with all software conversions