Data source: SingleRecordings/<id>/{hr.csv, rr.csv, timestamps.csv}
Scripts:
- plot_meditation_data.py: per-recording plots (raw + moving averages + segment boxplots)
- aggregate_segments_analysis.py: aggregate metrics/plots across recordings with exactly 4 marks (conditions)

How calculations are done

HR and RR loading
- Read timestamp (ms) → convert to datetime; set as index.
- HR column: hr (beats per minute). RR column: rr_ms (milliseconds).
Moving averages (per recording)
- Time-based rolling means over irregular timestamps using windows: 5 s, 10 s, 30 s, 60 s.
- X-axis is seconds from each recording’s start.
Mark handling (per recording)
- Vertical lines at marks from timestamps.csv.
- Segment boxplots use values in: each interval between consecutive marks and the final interval (last mark → end).
RMSSD (HRV)
- Definition: RMSSD = sqrt(mean(diff(RR_ms)^2)) using successive RR intervals (ms).
- Aggregate per-condition RMSSD: computed over all RR samples within each condition’s time window (recording-level); requires ≥2 RR samples.
- Aligned time-series RMSSD: first compute a 30 s time-based rolling RMSSD per recording, then align and average across recordings (see below).
Aggregate metrics across recordings (exactly 4 marks)
- Conditions (English labels):
  - Breathing Scene 1 (pre-first mark)
  - Spring Scene (1st–2nd mark)
  - Summer Scene (2nd–3rd mark)
  - Autumn Scene (3rd–4th mark)
  - Breathing Scene 2 (post-last mark)
- Per recording: compute medians for HR and RR within each condition; compute RMSSD within each condition.
- Summary CSV aggregates these per-recording values; boxplots show distributions. The mean of each condition is marked by a black dot on the boxplots.
Aligned average curves (HR, RR, RMSSD)
- Only recordings with exactly 4 marks are used.
- For each recording, durations of the five segments are measured; median segment proportions across recordings define a normalized 0–1 time axis with aligned boundaries.
- Each recording’s series is piecewise-linearly time-normalized to this axis, interpolated to a common grid, and then averaged (mean ± 1 SD). For RMSSD, a 30 s rolling RMSSD is used before alignment.

Results

Condition	HR (bpm)	RR (ms)	RMSSD (ms)
Breathing Scene 1	72.61	843.33	52.70
Spring Scene	72.33	860.78	56.95
Summer Scene	72.50	862.00	41.15
Autumn Scene	72.89	850.44	41.89
Breathing Scene 2	73.78	839.94	42.59