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== Article purpose == | == Article purpose == | ||
This article explains how to play audio through the [[ALSA overview|ALSA]] audio framework in '''Linux<sup>®</sup> OS''' context. | This article explains how to play audio through the [[ALSA overview|ALSA]] audio framework in '''Linux<sup>®</sup> OS''' context. | ||
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The [[ALSA overview|ALSA]] framework exposes audio devices associated to the board audio hardware interfaces. | The [[ALSA overview|ALSA]] framework exposes audio devices associated to the board audio hardware interfaces. | ||
The application audio streams are routed by default through the | The application audio streams are routed by default through the PulseAudio sound server. PulseAudio exposes audio profiles which are mapped on the ALSA sound card audio devices. The PulseAudio server provides a command line interface which allows to list audio profiles and to select a profile, to play on a specific audio interface. | ||
The audio playback examples in following sections are given for [[ALSA_overview#How_to_use|ALSA utilities]]. However, the audio playbacks can be launched by other applications, such as [[Gst-play|gstreamer]] multimedia framework. | The audio playback examples in following sections are given for [[ALSA_overview#How_to_use|ALSA utilities]]. However, the audio playbacks can be launched by other applications, such as [[Gst-play|gstreamer]] multimedia framework. | ||
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=== Audio playback on headset output === | === Audio playback on headset output === | ||
==== Playback on ALSA device ==== | |||
Run audio playback on 'playback_codec' ALSA device: | Run audio playback on 'playback_codec' ALSA device: | ||
{{Info|'playback_codec' is an alias defined in /etc/asound.conf, for headset output device.}} | {{Info|'playback_codec' is an alias defined in /etc/asound.conf, for headset output device.}} | ||
{{Board$}} aplay -D playback_codec /usr/share/sounds/alsa/Front_Left.wav | {{Board$}} aplay -D playback_codec /usr/share/sounds/alsa/Front_Left.wav | ||
* ''' | ==== Playback via PulseAudio ==== | ||
* '''Configure Pulseaudio''' | |||
Change the Pulseaudio active profile of the sound card, to 'analog-stereo' profile: | Change the Pulseaudio active profile of the sound card, to 'analog-stereo' profile: | ||
{{Info|The Pulseaudio analog-stereo profile is the default profile. So next command is not required after boot.}} | {{Info|The Pulseaudio analog-stereo profile is the default profile. So next command is not required after boot.}} | ||
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{{Board$}} pacmd set-card-profile 0 output:analog-stereo+input:analog-stereo | {{Board$}} pacmd set-card-profile 0 output:analog-stereo+input:analog-stereo | ||
Run audio playback: | * '''Run audio playback:''' | ||
{{Board$}} aplay /usr/share/sounds/alsa/Front_Left.wav | {{Board$}} aplay /usr/share/sounds/alsa/Front_Left.wav | ||
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{{Warning|The support of HDMI output is board dependent. Please, check available outputs with "''aplay -l''" command.}} | {{Warning|The support of HDMI output is board dependent. Please, check available outputs with "''aplay -l''" command.}} | ||
==== Playback on ALSA device ==== | |||
Run audio playback on 'playback_hdmi' ALSA device: | Run audio playback on 'playback_hdmi' ALSA device: | ||
{{Info|'playback_hdmi' is an alias defined in /etc/asound.conf, for hdmi output device.}} | {{Info|'playback_hdmi' is an alias defined in /etc/asound.conf, for hdmi output device.}} | ||
{{Board$}} aplay -D playback_hdmi /usr/share/sounds/alsa/Front_Left.wav | {{Board$}} aplay -D playback_hdmi /usr/share/sounds/alsa/Front_Left.wav | ||
* ''' | ==== Playback via PulseAudio ==== | ||
* '''Configure Pulseaudio''' | |||
Change the Pulseaudio active profile of the sound card, to 'hdmi-stereo' profile: | Change the Pulseaudio active profile of the sound card, to 'hdmi-stereo' profile: | ||
{{Info|Example below is given for {{highlight|sound card index 0}}. Check sound card index with "''pactl list cards short''" command.}} | {{Info|Example below is given for {{highlight|sound card index 0}}. Check sound card index with "''pactl list cards short''" command.}} | ||
{{Board$}} pacmd set-card-profile 0 output:hdmi-stereo | {{Board$}} pacmd set-card-profile 0 output:hdmi-stereo | ||
Run audio playback: | * '''Run audio playback:''' | ||
{{Board$}} aplay /usr/share/sounds/alsa/Front_Left.wav | {{Board$}} aplay /usr/share/sounds/alsa/Front_Left.wav | ||
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{{Info|S/PDIF ALSA device supports only {{highlight|32-bit audio streams}}. As 32-bit wave files are not provided in sample sound files, speaker-test is used instead of aplay, for convenience, here. Speaker-test generates a 440Hz sine wave in following examples.}} | {{Info|S/PDIF ALSA device supports only {{highlight|32-bit audio streams}}. As 32-bit wave files are not provided in sample sound files, speaker-test is used instead of aplay, for convenience, here. Speaker-test generates a 440Hz sine wave in following examples.}} | ||
==== Set IEC958 status bits ==== | |||
Example: set IEC958 mode bit. | |||
{{Board$}} iecset -c STM32MP1EV -n device=0 pro on | |||
==== Playback on ALSA device ==== | |||
Run audio playback on 'playback_spdif' ALSA device: | Run audio playback on 'playback_spdif' ALSA device: | ||
{{Info|'playback_spdif' is an alias defined in /etc/asound.conf, for S/PDIF output device.}} | {{Info|'playback_spdif' is an alias defined in /etc/asound.conf, for S/PDIF output device.}} | ||
{{Board$}} speaker-test -D playback_spdif -c 2 -F S32_LE -f 440 -t sine -l 1 | {{Board$}} speaker-test -D playback_spdif -c 2 -F S32_LE -f 440 -t sine -l 1 | ||
* ''' | ==== Playback via PulseAudio ==== | ||
* '''Configure Pulseaudio''' | |||
Change the sound card active profile, to S/PDIF 'iec958-stereo' profile. | Change the sound card active profile, to S/PDIF 'iec958-stereo' profile. | ||
{{Info|Example below is given for {{highlight|sound card index 0}}. Check sound card index with "''pactl list cards short''" command.}} | {{Info|Example below is given for {{highlight|sound card index 0}}. Check sound card index with "''pactl list cards short''" command.}} | ||
{{Board$}} pacmd set-card-profile 0 output:iec958-stereo | {{Board$}} pacmd set-card-profile 0 output:iec958-stereo | ||
Run audio playback: | * '''Run audio playback:''' | ||
{{Board$}} speaker-test -c 2 -F S32_LE -f 440 -t sine -l 1 | {{Board$}} speaker-test -c 2 -F S32_LE -f 440 -t sine -l 1 | ||
<noinclude> | |||
{{PublicationRequestId | 10391 | 2019-01-21}} | |||
[[Category:How to run use cases]] | |||
[[Category:ALSA]] | |||
</noinclude> | |||
Latest revision as of 19:17, 4 January 2021
1. Article purpose[edit source]
This article explains how to play audio through the ALSA audio framework in Linux® OS context. The examples below, show how to play audio on the different audio hardware interfaces of the STM32MPU boards.
2. Audio playback overview[edit source]
The ALSA framework exposes audio devices associated to the board audio hardware interfaces.
The application audio streams are routed by default through the PulseAudio sound server. PulseAudio exposes audio profiles which are mapped on the ALSA sound card audio devices. The PulseAudio server provides a command line interface which allows to list audio profiles and to select a profile, to play on a specific audio interface.
The audio playback examples in following sections are given for ALSA utilities. However, the audio playbacks can be launched by other applications, such as gstreamer multimedia framework.
3. Examples[edit source]
3.1. Audio playback on headset output[edit source]
3.1.1. Playback on ALSA device[edit source]
Run audio playback on 'playback_codec' ALSA device: Template:Info
Template:Board$ aplay -D playback_codec /usr/share/sounds/alsa/Front_Left.wav
3.1.2. Playback via PulseAudio[edit source]
- Configure Pulseaudio
Change the Pulseaudio active profile of the sound card, to 'analog-stereo' profile: Template:Info Template:Info
Template:Board$ pacmd set-card-profile 0 output:analog-stereo+input:analog-stereo
- Run audio playback:
Template:Board$ aplay /usr/share/sounds/alsa/Front_Left.wav
3.2. Audio playback on HDMI output[edit source]
3.2.1. Playback on ALSA device[edit source]
Run audio playback on 'playback_hdmi' ALSA device: Template:Info
Template:Board$ aplay -D playback_hdmi /usr/share/sounds/alsa/Front_Left.wav
3.2.2. Playback via PulseAudio[edit source]
- Configure Pulseaudio
Change the Pulseaudio active profile of the sound card, to 'hdmi-stereo' profile: Template:Info
Template:Board$ pacmd set-card-profile 0 output:hdmi-stereo
- Run audio playback:
Template:Board$ aplay /usr/share/sounds/alsa/Front_Left.wav
3.3. Audio playback on S/PDIF output[edit source]
Template:Warning Template:Info
3.3.1. Set IEC958 status bits[edit source]
Example: set IEC958 mode bit.
Template:Board$ iecset -c STM32MP1EV -n device=0 pro on
3.3.2. Playback on ALSA device[edit source]
Run audio playback on 'playback_spdif' ALSA device: Template:Info
Template:Board$ speaker-test -D playback_spdif -c 2 -F S32_LE -f 440 -t sine -l 1
3.3.3. Playback via PulseAudio[edit source]
- Configure Pulseaudio
Change the sound card active profile, to S/PDIF 'iec958-stereo' profile. Template:Info
Template:Board$ pacmd set-card-profile 0 output:iec958-stereo
- Run audio playback:
Template:Board$ speaker-test -c 2 -F S32_LE -f 440 -t sine -l 1