Raspberry Pi2での音声配信「USB Audio Device + FFserver」

前提:Raspberry Pi2にUSB Sound Deviceを接続し、音声ストリーミングを配信

Raspberry Pi2にて検証を行いましたが、基本的にはRaspberry Pi3/4でも同じ手順で動作すると思います。

lsusbにてデバイスの認識状況を確認。

「C-Media Electronics, Inc. CM108 Audio Controller」として認識。

$ lsusb
Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.
Bus 001 Device 004: ID 0d8c:013c C-Media Electronics, Inc. CM108 Audio Controller
Bus 001 Device 005: ID 0bda:2838 Realtek Semiconductor Corp. RTL2838 DVB-T

# 音声デバイスの優先度は以下のコマンドで確認ができます。
$ cat /proc/asound/modules
 0 snd_usb_audio
 1 snd_bcm2835

参考にさせていただきました。ありがとうございます。

RaspberryPI3にUSBマイクを接続して音声入力の設定を少しいじって録音しましたネットの情報を参考にしながら、最終的には、USBマイクでflac形式のファイルで録音するようにしました。USBマイクの優先順位のあげ方、soxのrecで

FFserver導入(release/2.8が一番安定)

FFserverは最新のffmpegにてサポート外となったので、FFserver対応のreleaseを git から取得(release/2.8 release/3.4はうまく動作せず)

# git "-b バージョン"にて、特定のバージョンをclone
git clone git://source.ffmpeg.org/ffmpeg.git -b release/2.8
Cloning into 'ffmpeg'...
remote: Enumerating objects: 614118, done.
remote: Counting objects: 100% (614118/614118), done.
remote: Compressing objects: 100% (124386/124386), done.
remote: Total 614118 (delta 493889), reused 607415 (delta 488483)
Receiving objects: 100% (614118/614118), 120.29 MiB | 336.00 KiB/s, done.
Resolving deltas: 100% (493889/493889), done.
Checking out files: 100% (6584/6584), done.


# makeには時間がかかるため、screenを起動 @2021/01/20 11:40

screen -R FFSERVER
cd ./ffmpeg
./configure

make && sudo make install

# 数時間後に、ffserverが作成されるので、confファイルを/etcにcopy
sudo cp ./ffserver.conf /etc/

cat /etc/ffserver.conf

http://server-ip:8090/ にてステータス表示

cat ./ffserver.conf

# Port on which the server is listening. You must select a different
# port from your standard HTTP web server if it is running on the same
# computer.
Port 8090

# Address on which the server is bound. Only useful if you have
# several network interfaces.
BindAddress 0.0.0.0

# Number of simultaneous HTTP connections that can be handled. It has
# to be defined *before* the MaxClients parameter, since it defines the
# MaxClients maximum limit.
MaxHTTPConnections 2000

# Number of simultaneous requests that can be handled. Since FFServer
# is very fast, it is more likely that you will want to leave this high
# and use MaxBandwidth, below.
MaxClients 1000

# This the maximum amount of kbit/sec that you are prepared to
# consume when streaming to clients.
MaxBandwidth 300
#MaxBandwidth 1000
#MaxBandwidth 50

# Access log file (uses standard Apache log file format)
# '-' is the standard output.
#CustomLog -
CustomLog /var/log/ffserver.log

# Suppress that if you want to launch ffserver as a daemon.
NoDaemon


##################################################################
# Definition of the live feeds. Each live feed contains one video
# and/or audio sequence coming from an ffmpeg encoder or another
# ffserver. This sequence may be encoded simultaneously with several
# codecs at several resolutions.

<Feed feed1.ffm>

# You must use 'ffmpeg' to send a live feed to ffserver. In this
# example, you can type:
#
# ffmpeg http://localhost:8090/feed1.ffm

# ffserver can also do time shifting. It means that it can stream any
# previously recorded live stream. The request should contain:
# "http://xxxx?date=[YYYY-MM-DDT][[HH:]MM:]SS[.m...]".You must specify
# a path where the feed is stored on disk. You also specify the
# maximum size of the feed, where zero means unlimited. Default:
# File=/tmp/feed_name.ffm FileMaxSize=5M
File /tmp/feed1.ffm
#FileMaxSize 200K
FileMaxSize 10000K

# You could specify
# ReadOnlyFile /saved/specialvideo.ffm
# This marks the file as readonly and it will not be deleted or updated.

# Specify launch in order to start ffmpeg automatically.
# First ffmpeg must be defined with an appropriate path if needed,
# after that options can follow, but avoid adding the http:// field
#Launch ffmpeg

# Only allow connections from localhost to the feed.
ACL allow 127.0.0.1

</Feed>


##################################################################
# Now you can define each stream which will be generated from the
# original audio and video stream. Each format has a filename (here
# 'test1.mpg'). FFServer will send this stream when answering a
# request containing this filename.

<Stream rpi2.mpg>

# coming from live feed 'feed1'
Feed feed1.ffm

# Format of the stream : you can choose among:
# mpeg       : MPEG-1 multiplexed video and audio
# mpegvideo  : only MPEG-1 video
# mp2        : MPEG-2 audio (use AudioCodec to select layer 2 and 3 codec)
# ogg        : Ogg format (Vorbis audio codec)
# rm         : RealNetworks-compatible stream. Multiplexed audio and video.
# ra         : RealNetworks-compatible stream. Audio only.
# mpjpeg     : Multipart JPEG (works with Netscape without any plugin)
# jpeg       : Generate a single JPEG image.
# asf        : ASF compatible streaming (Windows Media Player format).
# swf        : Macromedia Flash compatible stream
# avi        : AVI format (MPEG-4 video, MPEG audio sound)
#Format mpeg
Format mp2
#Format ogg -> NG
#Format swf -> NG

# Bitrate for the audio stream. Codecs usually support only a few
# different bitrates.
AudioBitRate 32
#AudioBitRate 16

# Number of audio channels: 1 = mono, 2 = stereo
AudioChannels 1

# Sampling frequency for audio. When using low bitrates, you should
# lower this frequency to 22050 or 11025. The supported frequencies
# depend on the selected audio codec.
#AudioSampleRate 44100
AudioSampleRate 22050

# Bitrate for the video stream
#VideoBitRate 64

# Ratecontrol buffer size
#VideoBufferSize 40

# Number of frames per second
#VideoFrameRate 3

# Size of the video frame: WxH (default: 160x128)
# The following abbreviations are defined: sqcif, qcif, cif, 4cif, qqvga,
# qvga, vga, svga, xga, uxga, qxga, sxga, qsxga, hsxga, wvga, wxga, wsxga,
# wuxga, woxga, wqsxga, wquxga, whsxga, whuxga, cga, ega, hd480, hd720,
# hd1080
#VideoSize 160x128

# Transmit only intra frames (useful for low bitrates, but kills frame rate).
#VideoIntraOnly

# If non-intra only, an intra frame is transmitted every VideoGopSize
# frames. Video synchronization can only begin at an intra frame.
#VideoGopSize 12

# More MPEG-4 parameters
# VideoHighQuality
# Video4MotionVector

# Choose your codecs:
AudioCodec mp2
#VideoCodec mpeg1video

# Suppress audio
#NoAudio

# Suppress video
NoVideo

#VideoQMin 3
#VideoQMax 31

# Set this to the number of seconds backwards in time to start. Note that
# most players will buffer 5-10 seconds of video, and also you need to allow
# for a keyframe to appear in the data stream.
Preroll 30

# ACL:

# You can allow ranges of addresses (or single addresses)
#ACL ALLOW <first address>

# You can deny ranges of addresses (or single addresses)
#ACL DENY <first address>

# You can repeat the ACL allow/deny as often as you like. It is on a per
# stream basis. The first match defines the action. If there are no matches,
# then the default is the inverse of the last ACL statement.
#
# Thus 'ACL allow localhost' only allows access from localhost.
# 'ACL deny 1.0.0.0 1.255.255.255' would deny the whole of network 1 and
# allow everybody else.

</Stream>


##################################################################
# Example streams


# Multipart JPEG

#<Stream test.mjpg>
#Feed feed1.ffm
#Format mpjpeg
#VideoFrameRate 2
#VideoIntraOnly
#NoAudio
#Strict -1
#</Stream>


# Single JPEG

#<Stream test.jpg>
#Feed feed1.ffm
#Format jpeg
#VideoFrameRate 2
#VideoIntraOnly
##VideoSize 352x240
#NoAudio
#Strict -1
#</Stream>


# Flash -> NG

#<Stream live.swf>
#Feed feed1.ffm
#Format swf
#VideoFrameRate 2
#VideoIntraOnly
#NoAudio
#NoVideo
#</Stream>


# ASF compatible

<Stream rpi2.asf>
Feed feed1.ffm
Format asf
VideoFrameRate 15
VideoSize 352x240
VideoBitRate 256
VideoBufferSize 40
VideoGopSize 30
AudioBitRate 64
StartSendOnKey
</Stream>


# MP3 audio

<Stream rpi2.mp3>
Feed feed1.ffm
Format mp2
AudioCodec mp2
#AudioBitRate 64
AudioBitRate 32
#AudioBitRate 16
AudioChannels 1
AudioSampleRate 44100
#AudioSampleRate 22050
PreRoll 500

NoVideo
</Stream>


# Ogg Vorbis audio

<Stream rpi2.ogg>
Feed feed1.ffm
Title "Stream title"
AudioBitRate 64
AudioChannels 2
AudioSampleRate 44100
NoVideo
</Stream>


# Real with audio only at 32 kbits

<Stream rpi2.ra>
Feed feed1.ffm
#Format rm
Format mp2
AudioBitRate 32
NoVideo
#PreRoll 50
PreRoll 5000
#NoAudio
</Stream>


# Real with audio and video at 64 kbits

#<Stream test.rm>
#Feed feed1.ffm
#Format rm
#AudioBitRate 32
#VideoBitRate 128
#VideoFrameRate 25
#VideoGopSize 25
#NoAudio
#</Stream>


##################################################################
# A stream coming from a file: you only need to set the input
# filename and optionally a new format. Supported conversions:
#    AVI -> ASF

#<Stream file.rm>
#File "/usr/local/httpd/htdocs/tlive.rm"
#NoAudio
#</Stream>

#<Stream file.asf>
#File "/usr/local/httpd/htdocs/test.asf"
#NoAudio
#Author "Me"
#Copyright "Super MegaCorp"
#Title "Test stream from disk"
#Comment "Test comment"
#</Stream>


##################################################################
# RTSP examples
#
# You can access this stream with the RTSP URL:
#   rtsp://localhost:5454/test1-rtsp.mpg
#
# A non-standard RTSP redirector is also created. Its URL is:
#   http://localhost:8090/test1-rtsp.rtsp

#<Stream test1-rtsp.mpg>
#Format rtp
#File "/usr/local/httpd/htdocs/test1.mpg"
#</Stream>


# Transcode an incoming live feed to another live feed,
# using libx264 and video presets

#<Stream live.h264>
#Format rtp
#Feed feed1.ffm
#VideoCodec libx264
#VideoFrameRate 24
#VideoBitRate 100
#VideoSize 480x272
#AVPresetVideo default
#AVPresetVideo baseline
#AVOptionVideo flags +global_header
#
#AudioCodec libfaac
#AudioBitRate 32
#AudioChannels 2
#AudioSampleRate 22050
#AVOptionAudio flags +global_header
#</Stream>

##################################################################
# SDP/multicast examples
#
# If you want to send your stream in multicast, you must set the
# multicast address with MulticastAddress. The port and the TTL can
# also be set.
#
# An SDP file is automatically generated by ffserver by adding the
# 'sdp' extension to the stream name (here
# http://localhost:8090/test1-sdp.sdp). You should usually give this
# file to your player to play the stream.
#
# The 'NoLoop' option can be used to avoid looping when the stream is
# terminated.

#<Stream test1-sdp.mpg>
#Format rtp
#File "/usr/local/httpd/htdocs/test1.mpg"
#MulticastAddress 224.124.0.1
#MulticastPort 5000
#MulticastTTL 16
#NoLoop
#</Stream>


##################################################################
# Special streams

# Server status

<Stream stat.html>
Format status

# Only allow local people to get the status
ACL allow localhost
ACL allow 192.168.0.0 192.168.255.255

#FaviconURL http://pond1.gladstonefamily.net:8080/favicon.ico
</Stream>


# Redirect index.html to the appropriate site

<Redirect index.html>
 URL http://www.ffmpeg.org/
</Redirect>

FFServer実行

/usr/local/bin/ffserver -f /etc/ffserver/ffserver.conf >> /tmp/FFserver_streaming.log

FFmpeg実行1 → NG alsaデバイスの不足

Starting ffmpeg
ffmpeg version n3.4.8-5-g8f5e16b5f1 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 8 (Raspbian 8.3.0-6+rpi1)
  configuration:
  libavutil      55. 78.100 / 55. 78.100
  libavcodec     57.107.100 / 57.107.100
  libavformat    57. 83.100 / 57. 83.100
  libavdevice    57. 10.100 / 57. 10.100
  libavfilter     6.107.100 /  6.107.100
  libswscale      4.  8.100 /  4.  8.100
  libswresample   2.  9.100 /  2.  9.100
Unknown input format: 'alsa'

不足ライブラリインストール(alsa)

sudo apt-get install libasound2-dev
cd ~/ffmpeg

./configure
 ... alsa! ..

make
./ffmpeg -formats |grep alsa
 ...  DE alsa! .. (the D/E columns indicate both directions are working

sudo make install

参考にしたページ

I have a Raspberry Pi 3 and I keep trying to install FFMPEG, but whenever I try to record audio through my USB webcam's mic with sudo ffmpeg -f alsa -i hw:1 -t...

FFmpeg実行2回目 → NG USB Sound Deviceの指定間違い

Starting ffmpeg
ffmpeg version n2.8.17 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 8 (Raspbian 8.3.0-6+rpi1)
  configuration:
  libavutil      55. 78.100 / 55. 78.100
  libavcodec     57.107.100 / 57.107.100
  libavformat    57. 83.100 / 57. 83.100
  libavdevice    57. 10.100 / 57. 10.100
  libavfilter     6.107.100 /  6.107.100
  libswscale      4.  8.100 /  4.  8.100
  libswresample   2.  9.100 /  2.  9.100
[alsa @ 0x2a32390] cannot open audio device hw:0,0 (No such file or directory)
hw:0,0: Input/output error

USB Sound Deviceの確認

書式:hw:card番号,device番号

「Card 1, device 0」 として認識されているので「hw:1,0」がSound Device

sudo aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: Headphones [bcm2835 Headphones], device 0: bcm2835 Headphones [bcm2835 Headphones]
  Subdevices: 8/8
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
  Subdevice #4: subdevice #4
  Subdevice #5: subdevice #5
  Subdevice #6: subdevice #6
  Subdevice #7: subdevice #7
card 1: Set [C-Media USB Headphone Set], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

FFmpeg実行3回目 -> OK!

# FFmpeg実行 
sudo /usr/local/bin/ffmpeg -ac 1 -f alsa -ar 4000 -i "hw:1,0" -acodec mp2 -ab 32k -ac 1 http://localhost:8090/feed1.ffm

ffmpeg version n2.8.17 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 8 (Raspbian 8.3.0-6+rpi1)
  configuration:
  libavutil      54. 31.100 / 54. 31.100
  libavcodec     56. 60.100 / 56. 60.100
  libavformat    56. 40.101 / 56. 40.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 40.101 /  5. 40.101
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.101 /  1.  2.101
Guessed Channel Layout for  Input Stream #0.0 : mono
Input #0, alsa, from 'hw:1,0':
  Duration: N/A, start: 1611211271.855956, bitrate: 705 kb/s
    Stream #0:0: Audio: pcm_s16le, 44100 Hz, 1 channels, s16, 705 kb/s
Output #0, ffm, to 'http://127.0.0.1:8090/feed1.ffm':
  Metadata:
    creation_time   : 2021-01-21 15:41:11
    encoder         : Lavf56.40.101
    Stream #0:0: Audio: mp2, 22050 Hz, mono, s16, 32 kb/s
    Metadata:
      encoder         : Lavc56.60.100 mp2
    Stream #0:1: Audio: wmav2, 22050 Hz, mono, fltp, 64 kb/s
    Metadata:
      encoder         : Lavc56.60.100 wmav2
    Stream #0:2: Audio: mp2, 44100 Hz, mono, s16, 32 kb/s
    Metadata:
      encoder         : Lavc56.60.100 mp2
    Stream #0:3: Audio: flac, 44100 Hz, stereo, s16, 64 kb/s
    Metadata:
      encoder         : Lavc56.60.100 flac
Stream mapping:
  Stream #0:0 -> #0:0 (pcm_s16le (native) -> mp2 (native))
  Stream #0:0 -> #0:1 (pcm_s16le (native) -> wmav2 (native))
  Stream #0:0 -> #0:2 (pcm_s16le (native) -> mp2 (native))
  Stream #0:0 -> #0:3 (pcm_s16le (native) -> flac (native))
Press [q] to stop, [?] for help
size=     984kB time=00:00:16.96 bitrate= 475.1kbits/s

配信状況の確認 http://server-ip:8090/

この時点でVLCなどでアドレス「http://server-ip:8090/rpi2.mpg」にて音声配信を受信できます。

入力音量の調整 sudo alsamixer

F6でデバイスを選択。ESCで終了。

参考:FFserver_FFmpeg_start-daemon.sh

#!/bin/bash

#prgfile=<Program Script filepath>

# FFserver
prgfile="/usr/local/bin/ffserver -f /etc/ffserver.conf > /dev/null 2>&1"
prgfile="/usr/local/bin/ffserver -loglevel quiet -f /etc/ffserver.conf > /dev/null 2>&1"
curdir="/home/knight/ffserver/"
prgtitle=ffserver
#pidfile=<PID filepath>
pidfile=/tmp/$prgtitle.pid

# FFmpeg
# x201
prgfile2="/usr/local/bin/ffmpeg -ac 2 -f alsa -ar 16000 -i default -loglevel quiet -acodec mp2 -ab 64k -ac 1 http://127.0.0.1:8090/feed1.ffm "
# Raspberry Pi
prgfile2="sudo /usr/local/bin/ffmpeg -ac 1 -f alsa -ar 4000 -i "hw:1,0" -loglevel quiet -acodec mp2 -ab 32k -ac 1 http://localhost:8090/feed1.ffm "
prgtitle2=ffmpeg
pidfile2=/tmp/$prgtitle2.pid

start() {
    if [ -f $pidfile ]; then
        pid=`cat $pidfile`
        kill -0 $pid >& /dev/null
        if [ $? -eq 0 ]; then
            echo "Daemon has started."
            return 1
        fi
    fi

    cd $curdir
    # Starting FFserver
    echo "Starting $prgfile"
    $prgfile &
    #pgrep -fl ffserver | awk '{print $1}' > $pidfile
    pgrep -fl $prgtitle | awk '{print $1}' > $pidfile

    # Starting FFmpeg
    sleep 1
    echo "Starting $prgfile2"
    $prgfile2 > /tmp/ffmpeg.log &
    #pgrep -fl ffserver | awk '{print $1}' > $pidfile2
    #pgrep -fl ffmpeg | awk '{print $1}' > $pidfile2
    pgrep -fl $prgtitle2 | awk '{print $1}' > $pidfile2

    if [ $? -eq 0 ]; then
        echo "Daemon started."
	pid=`cat $pidfile`
	pid2=`cat $pidfile2`
	echo "Daemon $prgtitle is started. (PID: ${pid})"
	echo "Daemon $prgtitle2 is started. (PID: ${pid2})"
        return 0
    else
        echo "Failed to start daemon."
        return 1
    fi
}

stop() {
    if [ ! -f $pidfile ]; then
        echo "Daemon not started."
        return 1
    fi

    pid=`cat $pidfile`
    pid2=`cat $pidfile2`
    kill $pid >& /dev/null
    if [ $? -ne 0 ]; then
        echo "Operation not permitted."
        return 1
    fi

    echo -n "Stopping daemon..."
    while true
    do
        kill -0 $pid >& /dev/null
        kill -0 $pid2 >& /dev/null
        if [ $? -ne 0 ]; then
            break
        fi

        sleep 2
        echo -n "."
    done

    rm -rf $pidfile
    rm -rf $pidfile2

    echo -e "\nDaemon stopped."
    return 0
}

status() {

    # FFserver
    if [ -f $pidfile ]; then
        pid=`cat $pidfile`
        pid2=`cat $pidfile2`
        kill -0 $pid >& /dev/null
        if [ $? -eq 0 ]; then
            echo "Daemon $prgtitle is running. (PID: ${pid})"
            echo "Daemon $prgtitle2 is running. (PID: ${pid2})"
            return 0
        else
            echo "Daemon might crash. (PID: ${pid} file remains)"
            return 1
        fi
    else
        echo "Daemon not started."
        return 0
    fi
}

restart() {
    stop
    if [ $? -ne 0 ]; then
        return 1
    fi

    sleep 2

    start
    return $?
}

case "$1" in
    start | stop | status | restart)
        $1
        ;;
    *)
        echo "Usage: $0 {start|stop|status|restart}"
        exit 2
esac

#exit $
exit 0