Estou executando nosso aplicativo de jogos de hardware embarcado executando o Ubuntu 16.0.4 LTS.
Eu quero remover os módulos pulseaudio e usar o ALSA diretamente de nosso aplicativo.
Eu removi pulseaudio usando o seguinte comando:
sudo apt-get --purge remove pulseaudio
Depois disso, reiniciei o sistema para permitir que o ALSA assumisse o sistema de som padrão sem pulseaudio.
As placas de som listadas em /proc/asound/cards são:
0 [HDMI ]: HDA-Intel - HDA Intel HDMI
HDA Intel HDMI at 0xf7430000 irq 33
1 [NVidia ]: HDA-Intel - HDA NVidia
HDA NVidia at 0xf3080000 irq 17
2 [amplifier ]: USB-Audio - 4.1 amplifier
4.1 amplifier at usb-0000:00:14.0-5, full speed
A saída de aplay -l é:
**** List of PLAYBACK Hardware Devices ****
card 0: HDMI [HDA Intel HDMI], device 3: HDMI 0 [HDMI 0]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: HDMI [HDA Intel HDMI], device 7: HDMI 1 [HDMI 1]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: HDMI [HDA Intel HDMI], device 8: HDMI 2 [HDMI 2]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 3: HDMI 0 [HDMI 0]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 7: HDMI 1 [HDMI 1]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 2: amplifier [4.1 amplifier], device 0: USB Audio [USB Audio]
Subdevices: 1/1
Subdevice #0: subdevice #0
A saída de aplay -L é:
null
Discard all samples (playback) or generate zero samples (capture)
pulse
PulseAudio Sound Server
hdmi:CARD=HDMI,DEV=0
HDA Intel HDMI, HDMI 0
HDMI Audio Output
hdmi:CARD=HDMI,DEV=1
HDA Intel HDMI, HDMI 1
HDMI Audio Output
hdmi:CARD=HDMI,DEV=2
HDA Intel HDMI, HDMI 2
HDMI Audio Output
dmix:CARD=HDMI,DEV=3
HDA Intel HDMI, HDMI 0
Direct sample mixing device
dmix:CARD=HDMI,DEV=7
HDA Intel HDMI, HDMI 1
Direct sample mixing device
dmix:CARD=HDMI,DEV=8
HDA Intel HDMI, HDMI 2
Direct sample mixing device
dsnoop:CARD=HDMI,DEV=3
HDA Intel HDMI, HDMI 0
Direct sample snooping device
dsnoop:CARD=HDMI,DEV=7
HDA Intel HDMI, HDMI 1
Direct sample snooping device
dsnoop:CARD=HDMI,DEV=8
HDA Intel HDMI, HDMI 2
Direct sample snooping device
hw:CARD=HDMI,DEV=3
HDA Intel HDMI, HDMI 0
Direct hardware device without any conversions
hw:CARD=HDMI,DEV=7
HDA Intel HDMI, HDMI 1
Direct hardware device without any conversions
hw:CARD=HDMI,DEV=8
HDA Intel HDMI, HDMI 2
Direct hardware device without any conversions
plughw:CARD=HDMI,DEV=3
HDA Intel HDMI, HDMI 0
Hardware device with all software conversions
plughw:CARD=HDMI,DEV=7
HDA Intel HDMI, HDMI 1
Hardware device with all software conversions
plughw:CARD=HDMI,DEV=8
HDA Intel HDMI, HDMI 2
Hardware device with all software conversions
hdmi:CARD=NVidia,DEV=0
HDA NVidia, HDMI 0
HDMI Audio Output
hdmi:CARD=NVidia,DEV=1
HDA NVidia, HDMI 1
HDMI Audio Output
dmix:CARD=NVidia,DEV=3
HDA NVidia, HDMI 0
Direct sample mixing device
dmix:CARD=NVidia,DEV=7
HDA NVidia, HDMI 1
Direct sample mixing device
dsnoop:CARD=NVidia,DEV=3
HDA NVidia, HDMI 0
Direct sample snooping device
dsnoop:CARD=NVidia,DEV=7
HDA NVidia, HDMI 1
Direct sample snooping device
hw:CARD=NVidia,DEV=3
HDA NVidia, HDMI 0
Direct hardware device without any conversions
hw:CARD=NVidia,DEV=7
HDA NVidia, HDMI 1
Direct hardware device without any conversions
plughw:CARD=NVidia,DEV=3
HDA NVidia, HDMI 0
Hardware device with all software conversions
plughw:CARD=NVidia,DEV=7
HDA NVidia, HDMI 1
Hardware device with all software conversions
default:CARD=amplifier
4.1 amplifier, USB Audio
Default Audio Device
sysdefault:CARD=amplifier
4.1 amplifier, USB Audio
Default Audio Device
front:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
Front speakers
surround21:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
4.0 Surround output to Front and Rear speakers
surround41:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
IEC958 (S/PDIF) Digital Audio Output
dmix:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
Direct sample mixing device
dsnoop:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
Direct sample snooping device
hw:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
Direct hardware device without any conversions
plughw:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
Hardware device with all software conversions
Quando pulseaudio foi instalado e executado no sistema, selecionei 4.1 Amplifier device em sound settings para Output e pude ouvir sons no teste de som. Mesmo VLC Player também funcionou bem.
Mas agora, depois de desinstalar pulseaudio , estou tentando reproduzir sons em card 2 USB-Audio - 4.1 amplifier devices listados em aplay -L , mas o volume é tão baixo que posso ouvir qualquer som.
Certifiquei-me de que o volume não estava protegido e definido como 100% para a placa de som 4.1 Amplifier em alsamixer , mas ainda assim o volume é super baixo.
Não tem certeza do que está acontecendo aqui?