zoukankan      html  css  js  c++  java
  • ALSA 常用command

    aplay/arecord:

    playback:

    aplay -D default xxx.wav

    list cards & devices:

    aplay -l

    record:

    aplay -C -D defaut -d 10 -f S16_LE -r 48000 -c 2 -t wav xxx.wav

    arecord -D defaut -d 10 -f S16_LE -r 48000 -c 2 -t wav xxx.wav

    amixer:

    show all controls for given card:

    amixer -c 0 controls

    amixer -Dhw:2 controls

    get control contents for one control:

    amixer -c 2 cget numid=1

    set control contents for one control:

    amixer -c 0 cset numid=1,iface=MIXER,name="Master Volume" 50

    amixer -c 0 cset name="Master Volume" 50 

    /proc

    list cards:

    cat /proc/asound/cards

    list devices:

    cat /proc/asound/devices

    ls -l /dev/snd

    list pcm:

    cat /proc/asound/pcm

    list  all devices for given card:

    ls -l /proc/asound/card0

    list information for given card & pcm & substream

    cat /proc/asound/card0/pcm0p/sub0/info

    card*/pcm*/info

    The general information of this PCM device: card #, device #, substreams, etc.
    card*/pcm*/xrun_debug

    This file appears when CONFIG_SND_DEBUG=y and CONFIG_PCM_XRUN_DEBUG=y. This shows the status of xrun (= buffer overrun/xrun) and invalid PCM position debug/check of ALSA PCM middle layer. It takes an integer value, can be changed by writing to this file, such as:

    # echo 5 > /proc/asound/card0/pcm0p/xrun_debug
    

    The value consists of the following bit flags:

    • bit 0 = Enable XRUN/jiffies debug messages
    • bit 1 = Show stack trace at XRUN / jiffies check
    • bit 2 = Enable additional jiffies check

    When the bit 0 is set, the driver will show the messages to kernel log when an xrun is detected. The debug message is shown also when the invalid H/W pointer is detected at the update of periods (usually called from the interrupt handler).

    When the bit 1 is set, the driver will show the stack trace additionally. This may help the debugging.

    Since 2.6.30, this option can enable the hwptr check using jiffies. This detects spontaneous invalid pointer callback values, but can be lead to too much corrections for a (mostly buggy) hardware that doesn’t give smooth pointer updates. This feature is enabled via the bit 2.

    card*/pcm*/sub*/info
    The general information of this PCM sub-stream.
    card*/pcm*/sub*/status
    The current status of this PCM sub-stream, elapsed time, H/W position, etc.
    card*/pcm*/sub*/hw_params
    The hardware parameters set for this sub-stream.
    card*/pcm*/sub*/sw_params
    The soft parameters set for this sub-stream.
    card*/pcm*/sub*/prealloc
    The buffer pre-allocation information.
    card*/pcm*/sub*/xrun_injection
    Triggers an XRUN to the running stream when any value is written to this proc file. Used for fault injection. This entry is write-only.
     
  • 相关阅读:
    学习笔记-Python基础19-结构化文件存储-xml
    学习笔记-Python基础18-asyncio异步、aiohttp、concurrent并发
    学习笔记-Python基础17-迭代器、生成器、协成
    学习笔记-Python基础16-多进程
    学习笔记-Python基础16-多线程
    Java中BigDecimal的一个除法异常
    JUnit单元测试入门
    Location search 属性
    struts2表单提交的乱码的问题的解决
    出现java.lang.NoSuchFieldException resourceEntries错误的解决方法
  • 原文地址:https://www.cnblogs.com/fellow1988/p/12397629.html
Copyright © 2011-2022 走看看