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Diffstat (limited to 'README.md')
| -rw-r--r-- | README.md | 48 |
1 files changed, 30 insertions, 18 deletions
@@ -1,10 +1,16 @@ Softmixer controller for 4A (AGL Advance Audio Architecture). ------------------------------------------------------------ - * Object: Simulate a hardware mixer through and Alsa-Loop driver and a user space mixer + * Object: Simulate a hardware mixer through and snd-aloop driver and a user space mixer * Status: In Progress * Author: Fulup Ar Foll fulup@iot.bzh - * Date : April-2018 + * Author: Thierry Bultel thierry.bultel@iot.bzh + * Date : July-2018 + +## Features + * Definition of multiple audio zones, and multiple audio cards + * Usage of streams to access audio zones + * Direct read from HW capture devices (eg radio chips & microphones) ## Compile ``` @@ -14,10 +20,10 @@ Softmixer controller for 4A (AGL Advance Audio Architecture). make ``` -## Install Alsa Loopback +## Install Alsa Loopback Driver ``` - sudo modprobe alsa-aloop + sudo modprobe snd-aloop ``` ## Assert LUA config file match your config @@ -46,28 +52,31 @@ Softmixer controller for 4A (AGL Advance Audio Architecture). # volid: volume alsa control you may change it from 'alsamixer -Dhw:Loppback' or with 'amixer -D hw:Loopback cset numid=103 NN (o-100%) ``` - - - Retrieve audio-stream alsa endpoint from response to 'L2C:snd_streams' command. Depending on your config 'hw:XXX' will change. Alsa snd-aloop impose '0' as playback device. Soft mixer will start from last subdevice and allocates one subdev for each audio-stream. ## Play some music -Current version does not handle audio rate conversion, using gstreamer or equivalent to match with audio hardware params is mandatory. -``` - export PROJECT_ROOT=`pwd` - gst123 --audio-output alsa=hw:Loopback,0,0 $PROJECT_ROOT/conf.d/project/sounds/trio-divi-alkazabach.mp3 +snd-aloop only supports these audio formats: - gst123 --audio-output alsa=hw:XXX,0,??? other sound file +S16_LE +S16_BE +S32_LE +S32_BE +FLOAT_LE +FLOAT_BE + +Using gstreamer is a simple way to perform the conversion, if your audio file is not of one of these. + +``` + gst-launch-1.0 filesrc location=insane.wav ! wavparse ! audioconvert ! audioresample ! alsasink device=hw:Loopback,0,2 - speaker-test -D hw:XXX:0:??? -twav -c!! 'cc' is the number of channel and depends on the audio stream zone target. ``` ## Warning -Alsa try top automatically store current state into /var/lib/alsa/asound.state when developing/testing this may create impossible +Alsa tries to automatically store current state into /var/lib/alsa/asound.state when developing/testing this may create impossible situation. In order to clean up your Alsa snd-aloop config, a simple "rmmod" might not be enough in some case you may have to delete /var/lib/alsa/asound.state before applying "modprobe". @@ -77,8 +86,11 @@ rmmod snd-aloop && modprobe --first-time snd-aloop && amixer -D hw:Loopback con ``` -Work in Progress +## Work in Progress + * Support capture from bluez + +## Known issues + * From times to times, playing an audio file make the sound output with higher pitch + * The playback loop could be improved, using direct access to the ring buffer instead + of copies to stack (could save some CPU time) - mise en place control pour master sur la carte playback/source - integration du cas d'un stream avec source non loop - test du rate converter
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