hugo/content/posts/judge_device.md
2022-04-04 15:59:13 +08:00

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title = "判断linux下音频输入对应的文件"
date = 2022-03-26
categories = ["bpf"]
draft = false
author = "Logic"
+++
## 判断音频输入 {#判断音频输入}
摄像头对应的设备属实是非常好找,但是麦克风对应的设备可就没那么容易了。本以为就应该是什么 `/dev/audio` 这样的东西,结果一看/dev文件夹看不出任何相关的存在。查找资料可以找到如下一张表格[^fn:1]
| ALSA設備 | OSS設備 | 次設備號 |
|----------------|------------------------|------|
| /dev/snd/pcmC0D0 | /dev/audio0/dev /audio | 4 |
| /dev/snd/pcmC0D0 | /dev/dsp0/dev/dsp | 3 |
| /dev/snd/pcmC0D1 | /dev/adsp/dev/adsp | 12 |
| /dev/snd/pcmC1D0 | /dev/audio1 | 20 |
| /dev/snd/pcmC1D0 | /dev/dsp1 | 19 |
| /dev/snd/pcmC1D1 | /dev/adsp1 | 28 |
| /dev/snd/pcmC2D0 | /dev/audio2 | 36 |
| /dev/snd/pcmC2D0 | /dev/dsp2 | 35 |
| /dev/snd/pcmC2D1 | /dev/adsp2 | 44 |
可见在使用alsa作为linux声音的驱动程序后alsa会创建一系列设备映射使用alsa设备就相当于使用对应的oss设备即麦克风。
[^fn:1]: The link is [理解和使用alsa配置](https://www.twblogs.net/a/5b7f76a12b717767c6afc8e2)