More usage for aplay/arecord/amixer may be obtained by the following commands.
• aplay --h
• arecord --h
• amixer --h
25.5.2 7.1 Audio Codec Unit Test
The 7.1 Audio codec driver supports multi-channel playback and record feature. The
codec has a default volume, and you can adjust volume by alsamixer command.
The playback feature can be tested by the following command:
• aplay [-Dplughw:0,0] audio.wav
While enabling ASRC, the 7.1 audio codec should use the device 1 for playback. The
codec has a default volume, and you can adjust volume by alsamixer command.
• aplay [-Dplughw:0,1] audio.wav
The recording feature supports line in and mic in simultaneously. While on i.MX 6
Sabre-AI board, LINE-IN (L/R) uses AIN1/AIN2, and MICS1/MICS2 uses AIN3/AIN4.
By default, 2-ch record uses AIN1/AIN2, and 4-ch record uses AIN1/AIN2/AIN3/AIN4
together.
The recording feature can be tested by following command:
• arecord [-Dplughw:0,0] -r 48000 -f S16_LE -c 2 -d 5 record.wav
Note:The default ALSA config file, asound.conf located under /etc/, only supports stereo
playback and record, which means, if you want to test 4,6,8-ch playback or 4-ch
recording, and use aplay audio.wav or arecord -c 4 audio.wav(without -Dplughw), you
will have to make slight changes to the configure file as following:
• Make sure that playback PCM uses dmix_48000 and capture PCM uses
dsnoop_48000 under pcm.asymed{}.
• Add "channels x" to the end of struct pcm.dmix_48000{} if you want to playback x-
ch wav file(x is greater than 2).
• Add "channels x" to the end of struct pcm.!dsnoop_48000{} if you want to record to
x-ch wav(x is greater than 2).
If plug plughw is used to make a playback or record, examples are as follows:
• aplay: Dplughw:0,0 audio.wav or
• arecord: Dplughw:0,0 -c 4 -r 48000 -f S16_LE record.wav
Unit Test
i.MX 6Solo/6DualLite Linux Reference Manual, Rev. L3.0.35_4.1.0, 09/2013
188
Freescale Semiconductor, Inc.
