Configuration File

DTrack has defaults that are designed to function adequately on a Raspberry Pi 5, although these make very poor monitoring devices. If your Selected Hardware provides a hardware video enconder, then it is important to modify record_save_options (below).

config.json

Configuration is stored in a JSON file, called config.json.

Important JSON Tips:

1. Format:

{
  "OPTION": VALUE,
  "OPTION": VALUE,
  "OPTION": VALUE
}

2. All VALUEs are one of:

string: "anythin inside of quotes"
list: ["like", "a", "string", "broken", "into", "parts"]
number: 5 or 3.1415
boolean: true for Yes or false for No

3. Every VALUE must have a trailing comma (,), except the last must not.

Test-Driven Defaults

Defaults were selected based on tests using lowest-recommended hardware.

Encoder Documentation (Upstream Defaults)

Value	Purpose
`-t <time>`	Must be set on each input device
`-tune zerolatency`	This is required for software encoding on low-end cpu
`-bufsize 64M`	Very large buffer to helps avoid processing spikes
`-crf 23`	Default is best; 25 reduces size by 30%, but 24 creates movement
`-maxrate 3M`	Hard quality limit, based on NO hardware encoding
	* 1080p recordings will see quality improvement up to about `7M`
	* Larger value creates larger files and XBUF for CPU-only encoding
`-preset fast`	Yield fewest XRUN errors
`-framerate 15`	Fast enough to catch most movement

Baseline Command:

ffmpeg -y -loglevel warning -nostdin -nostats \
    -t 00:10:00 -f alsa -i plughw \
    -t 00:10:00 -f v4l2 -i /dev/video0 \
    -map 0:a -c:a pcm_s16le -ar 48000 -ac 1 -f wav - \
    -filter_complex [1:v]...[dtstamp] -map 0:a -map [dtstamp] \
    -c:a pcm_s16le -ar 48000 -ac 1 -c:v libx264 baseline.mkv \
    >/dev/null