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我使用rpi dac在Raspberry Pi計算模塊(Linux)上運行良好的PCM音頻。該「aplay -l」命令的輸出顯示以下內容:ALSA配置如何在asound.conf中合併MMAP仿真和Ladspa插件
>> aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: sndrpirpidac [snd_rpi_rpi_dac], device 0: RPi-DAC HiFi pcm1794a-hifi-0 []
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: ALSA [bcm2835 ALSA], device 0: bcm2835 ALSA [bcm2835 ALSA]
Subdevices: 8/8
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
Subdevice #2: subdevice #2
Subdevice #3: subdevice #3
Subdevice #4: subdevice #4
Subdevice #5: subdevice #5
Subdevice #6: subdevice #6
Subdevice #7: subdevice #7
card 1: ALSA [bcm2835 ALSA], device 1: bcm2835 ALSA [bcm2835 IEC958/HDMI]
Subdevices: 1/1
Subdevice #0: subdevice #0
爲了讓聲音在所有的工作,我不得不改變我/etc/asound.conf文件,如下所示:
pcm.mmap0 {
type mmap_emul
slave {
pcm "hw:0,0"
}
}
pcm.!default {
type plug
slave {
pcm mmap0
}
}
當我播放.wav文件時,輸出聽起來不錯,但它有點安靜,alsamixer不允許使用此驅動程序進行音量控制。
我想要得到更多的音量,所以我研究了Ladspa項目軟件放大器插件。下面的示例代碼增強對正常皮3.5毫米插孔音量:
pcm.radio {
type plug
slave.pcm "ladspa"
hint {
show on
description "in -> equal -> declip -> compressor -> limiter -> dmix -> out"
}
}
# LADSPA plugins:
# "listplugins" to see the list of installed plugins
# "analyseplugin <filename>" to see plugin controls
# Use "ardour2" to experiment with plugin settings
pcm.ladspa {
type ladspa
slave.pcm "plughw:0,0"
path "/usr/lib/ladspa"
plugins {
0 {
# Limiter
label amp
input {
controls [ 10 ]
}
}
}
}
我一直在這裏閱讀文檔:http://alsa.opensrc.org/Asoundrc,但我有了解如何結合2掙扎 - 我想要的MMAP仿真以及放大。我怎樣才能做到這一點?謝謝。
你嘗試軟卷ALSA插件?似乎也放大了(有關詳細信息,請參閱http://www.alsa-project.org/alsa-doc/alsa-lib/pcm_plugins.html) –