# Fern RTSP Timelapse

## What

`fern_timelapse.py` is a small Linux-first Python 3.10+ CLI for two jobs:

- `capture`: take one JPEG from an RTSP camera, but only inside a configured daily window.
- `compile`: turn the saved JPEG sequence into a high-quality H.264 MP4.

It uses `ffmpeg` through `subprocess`, keeps timestamp-based filenames, writes rotating logs to disk, and retries failed captures with exponential backoff.

## Why

The design is intentionally cron-friendly. Each `capture` run is single-shot and idempotent enough for scheduled execution, which keeps the runtime simple and easy to recover after reboots or network drops. The `compile` path builds a temporary numbered sequence from symlinks so you can keep human-readable timestamp filenames without fighting ffmpeg's numeric-image input rules.

## Capture behavior

- Default window: `10:00` to `16:00`
- End of window is exclusive, so the default window captures from `10:00` through `15:50`
- Default quality: high-quality JPEG via `-q:v 2`
- Default output path shape: `captures/YYYY/MM/DD/YYYY-MM-DD_HH-MM-SS_ferngrowth.jpg`
- Default log file: `logs/fern_timelapse.log`

## Usage

Show command help:

```bash
python3 fern_timelapse.py --help
python3 fern_timelapse.py capture --help
python3 fern_timelapse.py compile --help
```

Capture one frame:

```bash
python3 fern_timelapse.py capture \
  --camera-host 192.168.1.50 \
  --camera-user user \
  --camera-password 'password' \
  --camera-path /stream1 \
  --output-dir /srv/fern-timelapse/captures \
  --window-start 10:00 \
  --window-end 16:00
```

Capture one frame even outside the allowed window:

```bash
python3 fern_timelapse.py capture \
  --camera-host 10.1.1.33 \
  --camera-user admin \
  --camera-password 'mirekadmin' \
  --camera-path /stream1 \
  --output-dir /mnt/main-pool/Mirek/kamera \
  --ignore-window
```

Your current camera parameters, assuming the RTSP path is `/stream1`:

```bash
python3 fern_timelapse.py capture \
  --camera-host 10.1.1.33 \
  --camera-user admin \
  --camera-password 'mirekadmin' \
  --camera-path /stream1 \
  --output-dir /srv/fern-timelapse/captures \
  --window-start 10:00 \
  --window-end 16:00
```

Compile the final MP4 at 30 FPS:

```bash
python3 fern_timelapse.py compile \
  --input-dir /srv/fern-timelapse/captures \
  --output-file /srv/fern-timelapse/output/ferngrowth_timelapse.mp4 \
  --fps 30 \
  --crf 17 \
  --preset slow
```

## Cron

This entry runs every 10 minutes during the 6-hour daylight window and should produce about 36 frames per day:

```cron
*/10 10-15 * * * /usr/bin/python3 /home/ms/projekty/paproc-rt/fern_timelapse.py capture --camera-host 10.1.1.33 --camera-user admin --camera-password 'mirekadmin' --camera-path /stream1 --output-dir /srv/fern-timelapse/captures --window-start 10:00 --window-end 16:00 >> /srv/fern-timelapse/cron.log 2>&1
```

If you prefer a simpler cron expression, you can also run it more broadly and let the script self-skip outside the window.

If your camera does not expose RTSP on `/stream1`, adjust `--camera-path`. Common alternatives include `/Streaming/Channels/101`, `/h264Preview_01_main`, or vendor-specific paths.

## Notes on exposure and white balance

There is no reliable generic ffmpeg flag that can force an RTSP camera to lock sensor-side auto-exposure or auto white balance. In practice, the cleanest fix for color flicker is:

1. Lock exposure and white balance in the camera's own web UI, ONVIF controls, or vendor app.
2. Keep lighting stable and avoid direct sun shifts.
3. Use `--ffmpeg-input-arg` or `--ffmpeg-output-arg` only for camera- or workflow-specific ffmpeg flags that your device actually supports.

Examples:

```bash
python3 fern_timelapse.py capture \
  --camera-host 192.168.1.50 \
  --camera-user user \
  --camera-password 'password' \
  --camera-path /stream1 \
  --ffmpeg-input-arg=-fflags \
  --ffmpeg-input-arg=+discardcorrupt
```