| 18 | | == Devices == |
| 19 | | The following commands are useful when dealing with multiple audio devices (These commands are done on a GW5400 which has multiple sources of audio in/out - different boards will have different devices at varied locations): |
| 20 | | * see a list of all audio cards: |
| 21 | | {{{ |
| 22 | | $ cat /proc/asound/cards |
| 23 | | 0 [sgtl5000audio ]: sgtl5000-audio - sgtl5000-audio |
| 24 | | sgtl5000-audio |
| 25 | | 1 [tda1997xaudio ]: tda1997x-audio - tda1997x-audio |
| 26 | | tda1997x-audio |
| 27 | | 2 [imxhdmisoc ]: imx-hdmi-soc - imx-hdmi-soc |
| 28 | | imx-hdmi-soc |
| 29 | | }}} |
| 30 | | * There are 3 audio cards in the system: |
| 31 | | * 0: sgtl5000audio (Analog Audio in/out) |
| 32 | | * 1: tda1997xaudio (HDMI Audio in) |
| 33 | | * 2: imxhdmisoc (HDMI Audio out) |
| 34 | | * Note that this is only available for playback if the framebuffer is not blanked |
| 35 | | * see a list of all playback devices: |
| 36 | | {{{ |
| 37 | | $ aplay -l |
| 38 | | **** List of PLAYBACK Hardware Devices **** |
| 39 | | card 0: sgtl5000audio [sgtl5000-audio], device 0: HiFi sgtl5000-0 [] |
| 40 | | Subdevices: 1/1 |
| 41 | | Subdevice #0: subdevice #0 |
| 42 | | card 2: imxhdmisoc [imx-hdmi-soc], device 0: IMX HDMI TX mxc-hdmi-soc-0 [] |
| 43 | | Subdevices: 1/1 |
| 44 | | Subdevice #0: subdevice #0 |
| 45 | | }}} |
| 46 | | * the above shows 2 playback capable devices: |
| 47 | | * card 0: the sgtl5000audio device which has one subdevice (0) - this can be represented as 'hw:0,0' |
| 48 | | * card 2: the imxhdmisoc device which has one subdevice (0) - this can be represented as 'hw:2,0' |
| 49 | | * Note that card 1 is not listed as it is an HDMI Audio input only and not capable of playback |
| 50 | | * see a list of all playback device 'names' |
| 51 | | {{{ |
| 52 | | $ aplay -L |
| 53 | | null |
| 54 | | Discard all samples (playback) or generate zero samples (capture) |
| 55 | | sysdefault:CARD=sgtl5000audio |
| 56 | | sgtl5000-audio, |
| 57 | | Default Audio Device |
| 58 | | sysdefault:CARD=imxhdmisoc |
| 59 | | imx-hdmi-soc, |
| 60 | | Default Audio Device |
| 61 | | }}} |
| 62 | | * the above shows 3 playback devices shown by name (Note that this is the name what can be used with 'aplay -D <devicename>' to specify playback device): |
| 63 | | * null - a null device |
| 64 | | * sysdefault:CARD=sgtl5000audio - Analog audio out |
| 65 | | * sysdefault:CARD=imxhdmisoc - HDMI audio out |
| 66 | | * see a list of all capture devices: |
| 67 | | {{{ |
| 68 | | root@ventana:~# arecord -l |
| 69 | | **** List of CAPTURE Hardware Devices **** |
| 70 | | card 0: sgtl5000audio [sgtl5000-audio], device 0: HiFi sgtl5000-0 [] |
| 71 | | Subdevices: 1/1 |
| 72 | | Subdevice #0: subdevice #0 |
| 73 | | card 1: tda1997xaudio [tda1997x-audio], device 0: IMX HDMI RX tda1997x-0 [] |
| 74 | | Subdevices: 1/1 |
| 75 | | Subdevice #0: subdevice #0 |
| 76 | | }}} |
| 77 | | * the above shows 2 capture capable devices: |
| 78 | | * card 0: the sgtl5000audio device which has one subdevice (0) - this can be represented as 'hw:0,0' |
| 79 | | * card 1: the tda1997xaudio device which has one subdevice (0) - this can be represented as 'hw:1,0' |
| 80 | | * Note that card 2 is not listed as it is an HDMI Audio output only and not capable of capture |
| 81 | | * see a list of all record device 'names': |
| 82 | | {{{ |
| 83 | | $ arecord -L |
| 84 | | null |
| 85 | | Discard all samples (playback) or generate zero samples (capture) |
| 86 | | sysdefault:CARD=sgtl5000audio |
| 87 | | sgtl5000-audio, |
| 88 | | Default Audio Device |
| 89 | | sysdefault:CARD=tda1997xaudio |
| 90 | | tda1997x-audio, |
| 91 | | Default Audio Device |
| 92 | | }}} |
| 93 | | * the above shows 3 capture devices shown by name (Note that this is the name what can be used with 'arecord -D <devicename>' to specify capture device): |
| 94 | | * 'null' - a null device |
| 95 | | * 'sysdefault:CARD=sgtl5000audio' - Analog audio in |
| 96 | | * 'sysdefault:CARD=tda1997xaudio' - HDMI audio in |
| 97 | | * display audio controls: |
| 98 | | {{{ |
| 99 | | amixer |
| 100 | | }}} |
| 101 | | * you can use the '-c <cardno>' parameter to amixer to specify a specific card (card number for /proc/asound/cards such as 'amixer -c 0' for the first card) |
| 102 | | * see 'amixer -h' for details on setting/getting various controls |
| 103 | | |
| 104 | | |
| 105 | | [=#amixer] |
| 106 | | == Mixer (mux/gain/volume) == |
| 107 | | The ALSA mixer controls the muxing of inputs to outputs, capture gains, and volume levels. The settings vary per card. |
| 108 | | |
| 109 | | You can use the amixer command to get/set/list available controls per card: |
| 110 | | * list controls for card0: |
| 111 | | {{{ |
| 112 | | amixer -c0 |
| 113 | | }}} |
| 114 | | |
| 115 | | |
