Problem with Audio
**Describe the bug**
Hello I have an error when Audio is on with an v4l2 camera + alsa device.

**To Reproduce**
The problem appear everytime I start the Video visualization in Home app. if I disable audio, all works fine.

Here is my config file :
```
"cameras": [
                {
                    "name": "Rpicam",
                    "motion": true,
                    "motionTimeout": 60,
                    "unbridge": true,
                    "hsv": true,
                    "prebuffering": true,
                    "prebufferLength": 4,
                    "videoConfig": {
                        "source": "-f video4linux2 -input_format h264 -framerate 25 -video_size hd720 -i /dev/video0 -f alsa -i default:CARD=Device",
                        "vcodec": "copy",
                        "audio": true,
                        "debug": true
                    },
                    "videoanalysis": {
                        "active": true
                    }
                }
```

**Logs**
Here are the Homebridge logs in debug mode : 
```
[1/13/2022, 12:48:39 PM] Homebridge v1.4.0-beta.4 (HAP v0.10.0-beta.7) (Homebridge 34EB) is running on port 53540.
[1/13/2022, 12:48:40 PM] [CameraUI] Rpicam: Setting up camera, please be patient...
[1/13/2022, 12:48:40 PM] [CameraUI] Rpicam: Probe stream: ffmpeg -f video4linux2 -input_format h264 -framerate 25 -video_size hd720 -i /dev/video0 -f alsa -i default:CARD=Device
[1/13/2022, 12:48:40 PM] [CameraUI] Rpicam: {"probe":true,"timedout":false,"audio":["pcm_s16le","48000 Hz","stereo","s16","1536 kb/s"],"video":["h264 (High)","yuv420p(progressive)","1280x720","25 fps","25 tbr","1000k tbn","2000k tbc"]}
[1/13/2022, 12:48:40 PM] [CameraUI] Rpicam: Incoming ping request for: /dev/video0 -f alsa  - Timeout: 1s
[1/13/2022, 12:48:40 PM] [CameraUI] Rpicam: Pinging /dev/video0 -f alsa  - successfull
[1/13/2022, 12:48:40 PM] [CameraUI] Rpicam: Start prebuffering...
[1/13/2022, 12:48:40 PM] [CameraUI] Rpicam: Prebuffering command: ffmpeg -hide_banner -loglevel error -fflags +genpts -f video4linux2 -input_format h264 -framerate 25 -video_size hd720 -i /dev/video0 -f alsa -i default:CARD=Device -vcodec copy -bsf:a aac_adtstoasc -acodec libfdk_aac -profile:a aac_low -flags +global_header -ar 8k -b:a 100k -ac 1 -f tee -map 0:v? -map 0:a? [movflags=frag_keyframe+empty_moov+default_base_moof:f=mp4]tcp://127.0.0.1:31319|[f=mpegts]tcp://127.0.0.1:20080
[1/13/2022, 12:48:41 PM] [CameraUI] Rpicam: Prebuffering scheduled for restart at 2AM: 791 minutes
[1/13/2022, 12:48:41 PM] [CameraUI] Rpicam: Incoming ping request for: /dev/video0 -f alsa  - Timeout: 1s
[1/13/2022, 12:48:41 PM] [CameraUI] Rpicam: Pinging /dev/video0 -f alsa  - successfull
[1/13/2022, 12:48:41 PM] [CameraUI] Rpicam: Start videoanalysis...
[1/13/2022, 12:48:41 PM] [CameraUI] Rpicam: Videoanalysis command: ffmpeg -hide_banner -loglevel error -hwaccel auto -analyzeduration 0 -probesize 500000 -f mpegts -i tcp://127.0.0.1:27137 -an -vcodec pam -pix_fmt rgba -f image2pipe -vf fps=2,scale=640:360 pipe:1
[1/13/2022, 12:48:41 PM] [CameraUI] Rpicam: Videoanalysis: Currently active zones: []
[1/13/2022, 12:48:41 PM] [CameraUI] Rpicam: Videoanalysis scheduled for restart at 3AM: 851 minutes
[1/13/2022, 12:48:42 PM] [CameraUI] Rpicam: Configuring unbridged accessory...
[1/13/2022, 12:48:42 PM] [CameraUI] Rpicam: Setting up accessory...
[1/13/2022, 12:48:42 PM] [CameraUI] Rpicam: Adding motion sensor service
[1/13/2022, 12:48:42 PM] [CameraUI] Rpicam: Initializing HomeKit Secure Video
[1/13/2022, 12:48:42 PM] [CameraUI] camera.ui v5.0.5 is listening on port 8081 (http)
[1/13/2022, 12:48:42 PM] Rpicam 5BC7 is running on port 46199.
[1/13/2022, 12:48:42 PM] Please add [Rpicam 5BC7] manually in Home app. Setup Code: 031-45-154
[1/13/2022, 12:48:49 PM] [CameraUI] Rpicam: Start stream requested: 1920x1080, 30 fps, 802 kbps
[1/13/2022, 12:48:49 PM] [CameraUI] Rpicam: Incoming ping request for: /dev/video0 -f alsa  - Timeout: 1s
[1/13/2022, 12:48:49 PM] [CameraUI] Rpicam: Pinging /dev/video0 -f alsa  - successfull
[1/13/2022, 12:48:49 PM] [CameraUI] Rpicam: Setting prebuffer stream as input
[1/13/2022, 12:48:49 PM] [CameraUI] Rpicam: Starting video stream: native
[1/13/2022, 12:48:49 PM] [CameraUI] Rpicam: Stream command: ffmpeg -hide_banner -loglevel level+verbose -analyzeduration 0 -probesize 3100684 -f mpegts -i tcp://127.0.0.1:35830 -an -sn -dn -vcodec copy -pix_fmt yuv420p -color_range mpeg -f rawvideo -payload_type 99 -ssrc 13233275 -f rtp -srtp_out_suite AES_CM_128_HMAC_SHA1_80 -srtp_out_params olWC8D5/55LfjPg2dTckqgnV8nngwHnnIim7WcBF srtp://192.168.50.167:50190?rtcpport=50190&pkt_size=1318 -vn -sn -dn -acodec libfdk_aac -profile:a aac_eld -flags +global_header -f null -ar 16k -b:a 24k -ac 1 -payload_type 110 -ssrc 6957011 -f rtp -srtp_out_suite AES_CM_128_HMAC_SHA1_80 -srtp_out_params PsJ4fF8LPDGQb9aQHt9G95+QrlOtoSKDg8xuAri0 srtp://192.168.50.167:52863?rtcpport=52863&pkt_size=188 -progress pipe:1
[1/13/2022, 12:48:49 PM] [CameraUI] Rpicam: [tcp @ 0xb6f2f650] [verbose] Starting connection attempt to 127.0.0.1 port 35830
[1/13/2022, 12:48:49 PM] [CameraUI] Rpicam: [tcp @ 0xb6f2f650] [verbose] Successfully connected to 127.0.0.1 port 35830
[1/13/2022, 12:48:49 PM] [CameraUI] Rpicam: [h264 @ 0xb6f32870] [verbose] Reinit context to 1280x720, pix_fmt: yuv420p
[1/13/2022, 12:48:50 PM] [CameraUI] Rpicam: [mpegts @ 0xb6f2f010] [verbose] max_analyze_duration 5000000 reached at 5037411 microseconds st:0
[1/13/2022, 12:48:50 PM] [CameraUI] Rpicam: [info] Input #0, mpegts, from 'tcp://127.0.0.1:35830':
[1/13/2022, 12:48:50 PM] [CameraUI] Rpicam: [info]   Duration: N/A, start: 2.958478, bitrate: N/A
[1/13/2022, 12:48:50 PM] [CameraUI] Rpicam: [info]   Program 1 
[1/13/2022, 12:48:50 PM] [CameraUI] Rpicam: [info]     Metadata:
[1/13/2022, 12:48:50 PM] [CameraUI] Rpicam: [info]       service_name    : Service01
[1/13/2022, 12:48:50 PM] [CameraUI] Rpicam: [info]       service_provider: FFmpeg
[1/13/2022, 12:48:50 PM] [CameraUI] Rpicam: [info]     Stream #0:0[0x100]: Video: h264 (High), 1 reference frame ([27][0][0][0] / 0x001B), yuv420p(progressive, left), 1280x720, 25 tbr, 90k tbn, 180k tbc
[1/13/2022, 12:48:50 PM] [CameraUI] Rpicam: [info] Output #1, rtp, to 'srtp://192.168.50.167:52863?rtcpport=52863&pkt_size=188':
[1/13/2022, 12:48:50 PM] [CameraUI] Rpicam: [error] Output file #1 does not contain any stream
[1/13/2022, 12:48:50 PM] [CameraUI] Rpicam: [AVIOContext @ 0x2b23290] [verbose] Statistics: 0 seeks, 0 writeouts
[1/13/2022, 12:48:50 PM] [CameraUI] Rpicam: [AVIOContext @ 0xb6f2f7b0] [verbose] Statistics: 2785168 bytes read, 0 seeks
[1/13/2022, 12:48:50 PM] [CameraUI] Rpicam: Prebuffer request ended
[1/13/2022, 12:48:50 PM] [CameraUI] Rpicam: FFmpeg exited with code: 1 and signal: null - [error] Output file #1 does not contain any stream
[1/13/2022, 12:48:50 PM] [CameraUI] Rpicam: Stopped video stream.
[1/13/2022, 12:48:53 PM] [CameraUI] Rpicam: Snapshot requested: 1280 x 720
[1/13/2022, 12:48:53 PM] [CameraUI] Rpicam: Snapshot command: ffmpeg -hide_banner -loglevel error -analyzeduration 0 -probesize 3096736 -f mpegts -i tcp://127.0.0.1:17187 -frames:v 1 -f image2 -
[1/13/2022, 12:48:53 PM] [CameraUI] Rpicam: Prebuffer request ended
```

**Environment**
- Homebridge Version: v1.4.0-beta.4 in Docker
- Camera UI Version: v5.0.5 
- Operating System: Raspbian Bullseye on RPI v4
- Browser: Home App in iOS
