Unknown encoder 'libfdk_aac'
**Describe the bug**
Everytime recording initiates, even with audio disabled, it tries to use an audio codec not in my ffmpeg installation. It appears the audio selection is unchangeable. As a result, I think it's erroring out my recording.

[1/17/2022, 1:12:50 AM] [CameraUI] Front Camera: Motion ON
[1/17/2022, 1:12:51 AM] [CameraUI] Front Camera: Video fragments requested from HSV
[1/17/2022, 1:12:51 AM] [CameraUI] Front Camera: Setting prebuffer stream as input
[1/17/2022, 1:12:51 AM] [CameraUI] Front Camera: Can not access prebuffer stream, skipping: Error: Prebuffer process not started!
[1/17/2022, 1:12:51 AM] [CameraUI] Front Camera: Replacing audio with a dummy track, audio source not found or timed out during probe stream (recording)
[1/17/2022, 1:12:51 AM] [CameraUI] Front Camera: Start recording...
[1/17/2022, 1:12:51 AM] [CameraUI] Front Camera: Recording command: ffmpeg -hide_banner -rtsp_transport tcp -re -i rtsp://admin:xxxx@xxxxx/cam/realmonitor?channel=1&subtype=0 -f lavfi -i anullsrc=cl=1 -shortest -f mp4 -sn -dn -vcodec libx264 -pix_fmt yuv420p -profile:v baseline -level:v 3.1 -b:v 2000k -force_key_frames expr:eq(t,n_forced*4) -r 30 -vf scale=w=1920:h=1080:force_original_aspect_ratio=1,pad=1920:1080:(ow-iw)/2:(oh-ih)/2 -bsf:a aac_adtstoasc -acodec libfdk_aac -profile:a aac_low -ar 32k -b:a 64k -ac 1 -movflags frag_keyframe+empty_moov+default_base_moof -max_muxing_queue_size 1024 tcp://127.0.0.1:26394
[1/17/2022, 1:12:55 AM] [CameraUI] Front Camera: Input #0, rtsp, from 'rtsp://admin:xxxx@xxxxx/cam/realmonitor?channel=1&subtype=0':
  Metadata:
    title           : Server
  Duration: N/A, start: 0.400000, bitrate: N/A

[1/17/2022, 1:12:55 AM] [CameraUI] Front Camera:   Stream #0:0: Video: hevc (Main), yuvj420p(pc, bt709), 2688x1520 [SAR 1:1 DAR 168:95], 5 fps, 5 tbr, 90k tbn, 5 tbc

[1/17/2022, 1:12:55 AM] [CameraUI] Front Camera: Input #1, lavfi, from 'anullsrc=cl=1':
  Duration: N/A, start: 0.000000, bitrate: 352 kb/s
  Stream #1:0: Audio: pcm_u8, 44100 Hz, 1 channels (FL), u8, 352 kb/s
[1/17/2022, 1:12:55 AM] [CameraUI] Front Camera: 

[1/17/2022, 1:12:55 AM] [CameraUI] Front Camera: Unknown encoder 'libfdk_aac'

[1/17/2022, 1:12:55 AM] [CameraUI] Front Camera: FFmpeg recording process exited with error! (null)
[1/17/2022, 1:13:00 AM] [CameraUI] Front Camera: Closing recording process
[1/17/2022, 1:13:00 AM] [CameraUI] Resetting motion state because HSV closed recording with reason "3"
[1/17/2022, 1:13:00 AM] [CameraUI] Front Camera: Motion OFF - Motion handler timeout.

==> /root/.pm2/logs/homebridge-error.log <==
[HDS ::ffff:192.168.1.28] Recording download stream 1 is still awaiting generator although stream was closed 10s ago!

**Environment**
- Node.js Version	v16.13.0
- Npm Version	v8.3.1
- Homebridge Version: v1.4.0-beta.7
- Camera UI Version: v5.0.8
- Operating System: Truenas
