BPI-R1 MIC
thank chaos.dennis do this test:
i write about this, because i found very few sources and had to tumble a lot around to get it working. This is a quick walk through to give you a hint where to start. I asume for simplicity that you stay always in /root directory as root user. If something fails, look if the files are written and paths are right. It is adressed for more advanced users who know what they are basically doing.
This is done with bananian 15.08 on Kernel 3.4. Other kernels < 4.4 do not work. It is a headless server with no HDMI pluged in.
A. Basic Setup
- Install alsa (renove pulseaudio if present):
# apt-get install alsa-base alsa-utils - Configure asound.conf
# nano /etc/asound.conf - Should look like:1pcm.!default {2type hw3card 0 # for headphone, turn 1 to 04device 05}6ctl.!default {7type hw8card 0 # for headphone, turn 1 to 09}Copied!
- Shutdown, make a cold boot
- Call the alsamixer
# alsamixerPress F5. Your channels should be setup like the attached file at the bottom of this post, or compare it to amixer output:1# amixer2Simple mixer control 'Master',03Capabilities: pvolume pvolume-joined4Playback channels: Mono5Limits: Playback 0 - 636Mono: Playback 45 [71%]7Simple mixer control 'Master Capture Mute',08Capabilities: pswitch pswitch-joined9Playback channels: Mono10Mono: Playback [off]11Simple mixer control 'LineL',012Capabilities: pswitch pswitch-joined13Playback channels: Mono14Mono: Playback [on]15Simple mixer control 'LineR',016Capabilities: pswitch pswitch-joined17Playback channels: Mono18Mono: Playback [on]19Simple mixer control 'Linein Pre-AMP',020Capabilities: volume volume-joined21Playback channels: Mono22Capture channels: Mono23Limits: 0 - 724Mono: 7 [100%]25Simple mixer control 'Mic Input Mux',026Capabilities: volume volume-joined27Playback channels: Mono28Capture channels: Mono29Limits: 0 - 1530Mono: 15 [100%]31Simple mixer control 'Mic Power',032Capabilities: pswitch pswitch-joined33Playback channels: Mono34Mono: Playback [on]35Simple mixer control 'Mic1 Boost',036Capabilities: pswitch pswitch-joined37Playback channels: Mono38Mono: Playback [on]39Simple mixer control 'Mic1 gain',040Capabilities: volume volume-joined41Playback channels: Mono42Capture channels: Mono43Limits: 0 - 344Mono: 3 [100%]45Simple mixer control 'Mic2 Boost',046Capabilities: pswitch pswitch-joined47Playback channels: Mono48Mono: Playback [on]49Simple mixer control 'Mic2 gain',050Capabilities: volume volume-joined51Playback channels: Mono52Capture channels: Mono53Limits: 0 - 754Mono: 0 [0%]55Simple mixer control 'MicL',056Capabilities: volume volume-joined57Playback channels: Mono58Capture channels: Mono59Limits: 0 - 360Mono: 1 [33%]61Simple mixer control 'MicR',062Capabilities: volume volume-joined63Playback channels: Mono64Capture channels: Mono65Limits: 0 - 366Mono: 3 [100%]67Simple mixer control 'Playback',068Capabilities: pswitch pswitch-joined69Playback channels: Mono70Mono: Playback [on]71Simple mixer control 'Capture',072Capabilities: cvolume cvolume-joined73Capture channels: Mono74Limits: Capture 0 - 775Mono: Capture 7 [100%]76Simple mixer control 'ADC Input Mux',077Capabilities: volume volume-joined78Playback channels: Mono79Capture channels: Mono80Limits: 0 - 781Mono: 7 [100%]82Simple mixer control 'Fm output',083Capabilities: volume volume-joined84Playback channels: Mono85Capture channels: Mono86Limits: 0 - 787Mono: 7 [100%]88Simple mixer control 'FmL',089Capabilities: pswitch pswitch-joined90Playback channels: Mono91Mono: Playback [on]92Simple mixer control 'FmR',093Capabilities: pswitch pswitch-joined94Playback channels: Mono95Mono: Playback [on]96Simple mixer control 'LINEIN APM',097Capabilities: volume volume-joined98Playback channels: Mono99Capture channels: Mono100Limits: 0 - 7101Mono: 7 [100%]102Simple mixer control 'Ldac Left Mixer',0103Capabilities: pswitch pswitch-joined104Playback channels: Mono105Mono: Playback [on]106Simple mixer control 'Ldac Right Mixer',0107Capabilities: pswitch pswitch-joined108Playback channels: Mono109Mono: Playback [on]110Simple mixer control 'Left Capture Mute',0111Capabilities: pswitch pswitch-joined112Playback channels: Mono113Mono: Playback [on]114Simple mixer control 'MIC output volume',0115Capabilities: volume volume-joined116Playback channels: Mono117Capture channels: Mono118Limits: 0 - 7119Mono: 7 [100%]120Simple mixer control 'Rdac Right Mixer',0121Capabilities: pswitch pswitch-joined122Playback channels: Mono123Mono: Playback [on]124Simple mixer control 'Right Capture Mute',0125Capabilities: pswitch pswitch-joined126Playback channels: Mono127Mono: Playback [on]Copied!This step is critical. One false muted channel and you are out of the game. - Test recording.
# arecord -LShould show a device.# arecord -f S16_LE -r 44100 -t wav test.wavShould make kind of Sound. Stop it with ctr-c and check the file.
B. SoX Recording / Streaming
- Install SoX
# apt-get install sox libsox-fmt-allSox gives you tools like: sox, rec and play. I would suggest you install it on the client pc too. - Record striaght to mp31# rec -c 2 -C 64 test.mp3Copied!-c 2 two channels-C 64 tell the encoder to produce a 64kbit/s mp3Stop it with ctr-c, check the output.
- Listen to it live over LANBanana:
# rec -c 2 -C 64 -t mp3 - | netcat -l -p 9000-t mp3 - produce mp3 stream to stdoutClient:# netcat <banana ip> 9000 | vlcWorks? Great! Live listening is important to play around and test the mic. - Listen and record at same time
# rec -c 2 -C 64 -t mp3 - | tee test.mp3 | netcat -l -p 9000 - Poor man's streaming server1# apt-get install openbsd-inetd tcpdCopied!Edit config file:1# nano /etc/inetd.confCopied!Insert this at the end:19000 stream tcp nowait nobody /usr/bin/tail tail -f /test.mp3Copied!Restart service1# service openbsd-inetd restartCopied!Start recording on banana:1# rec -c 2 -C 64 /test.mp3Copied!Connect via client:1# netcat <banana ip> 9000 | vlc -Copied!
C. Advanced Recording
- Devide recording and postprocessing in two parts1# rec -t raw - remix - | sox -t raw -r 48000 -c 1 -b 16 -e signed-integer - -t mp3 -c 1 -C 32 test.mp3Copied!
Recording:
-t raw - forward raw input to pipe
remix - Mix the two channels to one
Encoding:
-t raw -r 48000 -c 1 -b 16 -e signed-integer - tell sox what kind of strean comes from stdin
-t mp3 -c 1 -C 32 test.mp3 and what goes out
Note that it is switched to mono from here with -c 1 and the mp3 bitrate is cut in half. Live listening to the strean does not work anymore, i asume it is because of the non regulare output from pipeing and processing in a second step.
- Reduce noiseThe mic input is pretty bad, lot of white noise. Sox can deal with it.Make a sample "silent" file:1# rec -t raw test.raw remix - trim 0 10Copied!trim 0 10 record 10 secondsTest it at client pc:1# play -r 48000 -c 1 -b 16 -e signed-integer test.rawCopied!Create profile file:1# sox -r 48000 -c 1 -b 16 -e signed-integer test.raw -n trim 0 2 noiseprof raw-profileCopied!Record with noise canceld1# rec -t raw - remix - noisered raw-profile 0.2 | sox -t raw -r 48000 -c 1 -b 16 -e signed-integer - -t mp3 -c 1 -C 32 test.mp3Copied!Play with the factor of 0.2 to regulate the intensity of cancellation.
D. Record 24/7
My goal of this....
Create a script:
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# nano /root/record.sh
Copied!
Insert the following:
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#!/bin/bash
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​
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# send sigterm and wait for exit of the process
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function stop() { kill [email protected]; while kill -0 [email protected]; do sleep 1; done; }
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function log() { echo $(date +%T) [email protected]; }
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​
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log "Stopping previus recording"
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stop `pidof rec` &> /dev/null
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​
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DATE=`date "+%Y.%m.%d"`
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log "Recording $DATE.mp3"
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rec -q -t raw - remix - noisered /root/raw-profile 0.2 | \
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sox -v 2.0 -t raw -r 48000 -c 1 -b 16 -e signed-integer - \
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-t mp3 -r 22050 -c 1 -C -9.2 /root/$DATE.mp3
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log "Done $DATE.mp3"
Copied!
Recording:
-q less output
Encoding: -v 2.0 Make the input stream louder
-r 22050 encode to a lower sample rate
-C -9.2 Create a low quality VBR mp3
Fileszie ~100mb per day. If you want smaller files, a 8000 sanple rate gives you a gsm grade quality.
Make it executable
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# chmod +x record.sh
Copied!
Edit crontab:
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# env EDITOR=nano crontab -e
Copied!
Insert at the end the following:
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PATH=/usr/local/bin:/usr/local/sbin:/sbin:/usr/sbin:/bin:/usr/bin
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0 0 * * * /root/record.sh >> /root/re cord-mic.log
Copied!
A new recording should start every day at midnight.
Last modified 2yr ago
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