The Armadillo-440 LCD Model incorporates an audio codec and can both record and play sound. For the specifications of the audio driver, refer to "Audio" in the "Armadillo-400 Series Software Manual." This chapter explains how to record and play sound.
7.1. Sound Functionality With ALSA
There are two ways to provide audio functionality on Linux: ALSA[] and OSS[]. ALSA is used by default on the Armadillo-440 LCD Model.
7.1.1. Playing Back Sound
The aplay command is used to play sound with ALSA. See below for details on the options. For information on all available options, refer to the aplay help.
- -M
Use memory mapped I/O for the audio stream.
- -t
Specify the file type. Refer to the help for what file types can be specified.
- -f
Specify the sample format. Refer to the help for what sample formats can be specified.
- -d
End after the specified number of seconds.
- -l
List all sound cards and audio devices.
- -L
List all defined PCM.
- -c
Specify the number of channels.
- -r
Specify the sample rate.
- -D
Specify the PCM.
- -h
Display help.
The arecord command is used to record sound with ALSA.
The arecord options are the same as those for aplay.
The amixer command is used to change the recording and playback volume with ALSA.
The control name to be changed should be specified for [control]. Refer to 表7.1「Control Names」 for the supported control names.
表7.1 Control Names
| Control | Description |
|---|
| 'Headphone' | Headphone volume |
| Mic | Microphone volume |
Enter the command below to check all of the controls and their values.
The volume is specified in place of [value] with a range of 0 (mute) to 63 (max).
