amixer ###### Usage:: amixer [command] 基本语法:: $ amixer -card -device -card :指定要控制的声卡,默认为 0 -device :指定声卡上的设备,默认为 0 :要设置的混音器控件,如音量、静音等 :要设置的值,可为 on/off,0-100% 等 - amixer -c 1 sset Master 70%: 将第二块声卡(card 1)的主音量(Master)设置为 70% - amixer -D hw:0,3 cset Capture toggle: 将第三个设备(device 3)的录音通道(Capture)开/关 - amixer cset numid=34,iface=MIXER,name='Line In' 80%: 通过控件的ID和名称设置输入通道80% Available options:: -c,--card N select the card -D,--device N select the device, default 'default' -d,--debug debug mode -n,--nocheck do not perform range checking -v,--version print version of this program -q,--quiet be quiet -i,--inactive show also inactive controls -a,--abstract L select abstraction level (none or basic) -s,--stdin Read and execute commands from stdin sequentially -R,--raw-volume Use the raw value (default) -M,--mapped-volume Use the mapped volume Available commands:: scontrols show all mixer simple controls scontents show contents of all mixer simple controls (default command) sset sID P set contents for one mixer simple control sget sID get contents for one mixer simple control controls show all controls for given card contents show contents of all controls for given card cset cID P set control contents for one control cget cID get control contents for one control Available advanced commands:: sevents show the mixer events for simple controls events show the mixer events for simple controls 说明 ==== amixer 是 ALSA 提供的命令行混音器控制工具:: 1. 查看和控制声卡上的所有混音器控件,如音量控制、静音控制、捕捉选项等 2. 设置混音器控件的值,如设置音量、开/关静音等 3. 保存和恢复混音器的状态 名称说明:: 1. Master:主控件,影响所有的音频内容与输出设备。用于控制系统的总体音量。当其值为 0 时,所有输出均无音频信号。 2. PCM:专门影响数字音频信号的大小,用于调整数字音频内容(如电影、音乐)的播放音量。其它模拟音频内容(如系统提示音)不受影响。但若为 0 时,数字音频内容也无输出。 3. Speaker:只影响内建扬声器或扩音器的音量输出。用于专门控制这些输出设备的音量大小与开关。为 0 时,只有扬声器/扩音器无音频输出,耳机或其它接口输出可正常工作。 4. Headphone 只影响耳机输出 5. Mic Boost:麦克风增益控件,用于增强麦克风输入的信号。0 到 3 的范围,当前为关闭状态。 6. Capture:录音输入控件,用于开关录音输入和控制录音音量。0 到 63 的范围,当前最大 63,开启状态。注意：只有此值为开启状态录音才有声音。 7. Auto-Mute Mode:自动静音模式控件,用于启用或禁用自动静音功能。当前为 ‘Disabled’ 禁用状态。 8. Internal Mic Boost:此控件与麦克风增益控件功能类似,也用于控制输入信号的增益。当前也为最大值 3 和 30dB 的增益。 - Master、PCM、Speaker、Headphone 用于控制播放相关的音量和开关。 - Capture、Mic Boost、Internal Mic Boost 用于控制录音输入相关的增益和音量。 - Auto-Mute Mode 为辅助功能,可以自动静音。 示例 ==== 示例1: $ amixer -c 0:: Simple mixer control 'Mic ACP LED',0 Capabilities: cswitch cswitch-joined Capture channels: Mono Mono: Capture [off] Simple mixer control 'IEC958',0 Capabilities: pswitch pswitch-joined Playback channels: Mono Mono: Playback [off] Simple mixer control 'IEC958',1 Capabilities: pswitch pswitch-joined Playback channels: Mono Mono: Playback [off] 说明: Capabilities: - cswitch:捕捉开/关开关 - pswitch:播放开/关开关 Capture channels / Playback channels: - 表示此控件对应的录音/播放通道,这里都是 Mono(单通道) Mono/Stereo: - 显示控件当前的开/关状态 示例2(插耳机前): $ amixer -c 1:: Simple mixer control 'Master',0 Capabilities: pvolume pvolume-joined pswitch pswitch-joined Playback channels: Mono Limits: Playback 0 - 87 Mono: Playback 59 [68%] [-21.00dB] [on] Simple mixer control 'Headphone',0 Capabilities: pvolume pswitch Playback channels: Front Left - Front Right Limits: Playback 0 - 87 Mono: Front Left: Playback 0 [0%] [-65.25dB] [off] Front Right: Playback 0 [0%] [-65.25dB] [off] Simple mixer control 'Speaker',0 Capabilities: pvolume pswitch Playback channels: Front Left - Front Right Limits: Playback 0 - 87 Mono: Front Left: Playback 87 [100%] [0.00dB] [on] Front Right: Playback 87 [100%] [0.00dB] [on] Simple mixer control 'PCM',0 Capabilities: pvolume Playback channels: Front Left - Front Right Limits: Playback 0 - 255 Mono: Front Left: Playback 255 [100%] [0.00dB] Front Right: Playback 255 [100%] [0.00dB] Simple mixer control 'Mic Boost',0 Capabilities: volume Playback channels: Front Left - Front Right Capture channels: Front Left - Front Right Limits: 0 - 3 Front Left: 0 [0%] [0.00dB] Front Right: 0 [0%] [0.00dB] Simple mixer control 'Capture',0 Capabilities: cvolume cswitch Capture channels: Front Left - Front Right Limits: Capture 0 - 63 Front Left: Capture 63 [100%] [30.00dB] [off] Front Right: Capture 63 [100%] [30.00dB] [off] Simple mixer control 'Auto-Mute Mode',0 Capabilities: enum Items: 'Disabled' 'Enabled' Item0: 'Disabled' Simple mixer control 'Internal Mic Boost',0 Capabilities: volume Playback channels: Front Left - Front Right Capture channels: Front Left - Front Right Limits: 0 - 3 Front Left: 3 [100%] [30.00dB] Front Right: 3 [100%] [30.00dB] 说明: 6 个混音器控件: - Master: 主音量控制, 开启 - Headphone: 耳机控制, 关闭 - Speaker: 扬声器控制, 开启 - PCM: 数字音频信号控制 - Mic Boost:麦克风增益控制, - Capture:录音控制, 开启 - Auto-Mute Mode: 自动静音模式选择,当前为 'Disabled' - Internal Mic Boost: 麦克风控件,当前关闭 Capabilities: - pvolume:音量控制 - pswitch:播放开/关 - cvolume:录音音量 - cswitch:录音开/关 - enum:选择项 其他: [on]/[off] 表示开/关状态, [100%] 表示相对最大值的百分比, [-4.50dB] 为实际衰减值 示例3(插耳机后): $ amixer -c 1:: Simple mixer control 'Master',0 Capabilities: pvolume pvolume-joined pswitch pswitch-joined Playback channels: Mono Limits: Playback 0 - 87 Mono: Playback 54 [62%] [-24.75dB] [on] Simple mixer control 'Headphone',0 Capabilities: pvolume pswitch Playback channels: Front Left - Front Right Limits: Playback 0 - 87 Mono: Front Left: Playback 87 [100%] [0.00dB] [on] Front Right: Playback 87 [100%] [0.00dB] [on] Simple mixer control 'Speaker',0 Capabilities: pvolume pswitch Playback channels: Front Left - Front Right Limits: Playback 0 - 87 Mono: Front Left: Playback 0 [0%] [-65.25dB] [off] Front Right: Playback 0 [0%] [-65.25dB] [off] Simple mixer control 'PCM',0 Capabilities: pvolume Playback channels: Front Left - Front Right Limits: Playback 0 - 255 Mono: Front Left: Playback 255 [100%] [0.00dB] Front Right: Playback 255 [100%] [0.00dB] Simple mixer control 'Mic Boost',0 Capabilities: volume Playback channels: Front Left - Front Right Capture channels: Front Left - Front Right Limits: 0 - 3 Front Left: 3 [100%] [30.00dB] Front Right: 3 [100%] [30.00dB] Simple mixer control 'Capture',0 Capabilities: cvolume cswitch Capture channels: Front Left - Front Right Limits: Capture 0 - 63 Front Left: Capture 63 [100%] [30.00dB] [off] Front Right: Capture 63 [100%] [30.00dB] [off] Simple mixer control 'Auto-Mute Mode',0 Capabilities: enum Items: 'Disabled' 'Enabled' Item0: 'Disabled' Simple mixer control 'Internal Mic Boost',0 Capabilities: volume Playback channels: Front Left - Front Right Capture channels: Front Left - Front Right Limits: 0 - 3 Front Left: 0 [0%] [0.00dB] Front Right: 0 [0%] [0.00dB] 说明: Headphone 控件打开,因为插入耳机后声音输出到耳机。原来该控件显示为关闭状态 [off]。 Speaker 控件关闭,因为插入耳机后声音不再从扬声器输出。原来该控件显示为打开状态 [on]。 示例2、3对比说明:: 1. 不带耳机时: - Speaker 控件显示为开启,这很可能对应内建扬声器 - Headphone 控件显示为关闭 - Internal Mic Boost 为 3 [100%],Mic Boost 为 0 [0%] 2. 带耳机时: - Headphone 控件显示为开启,这对应插入的耳机 - Speaker 控件显示为关闭 - Internal Mic Boost 为 0 [0%],Mic Boost 未变化仍为 3 [100%]