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Video Creation from Simulation Plots

This document describes how to create videos from saved FLORIDyn simulation plots.

Overview

FLORIDyn.jl now includes functionality to automatically convert series of PNG plot files into MP4 videos. This is particularly useful for creating animations of flow field evolution over time.

Prerequisites

  • FFmpeg: Must be installed and available in your system PATH
    • Ubuntu/Debian: sudo apt install ffmpeg
    • MacOS: brew install ffmpeg
    • Windows: Download from https://ffmpeg.org/

Basic Usage

1. Generate Plot Frames

First, run your simulation with vis.save=true to save plot frames:

using FLORIDyn

# Enable plot saving
vis = Vis(online=true, save=true, rel_v_min=20.0, up_int=12)

# Run simulation - this will save frames to the 'video/' folder
wf, md, mi = runFLORIDyn(plt, set, wf, wind, sim, con, vis, floridyn, floris)

2. Create Videos

Create videos from the saved frames:

# Create video from velocity reduction frames
video_path = createVideo("velocity_reduction"; fps=4)

# Custom video creation with options
custom_video = createVideo("wind_speed"; 
                          video_dir="video", 
                          output_dir="animations", 
                          fps=8, 
                          delete_frames=true)

Functions

createVideo(prefix; kwargs...)

Convert PNG files starting with a given prefix into an MP4 video.

Arguments:

  • prefix::String: Prefix of PNG files to include (e.g., "velocity_reduction")
  • video_dir::String: Input directory (default: "video")
  • output_dir::String: Output directory (default: "video")
  • fps::Int: Frames per second (default: 2)
  • delete_frames::Bool: Delete PNG files after creating video (default: false)

Returns: Path to created video file, or empty string if failed

Supported prefixes:

  • "velocity_reduction" - Velocity reduction animations
  • "added_turbulence" - Added turbulence animations
  • "wind_speed" - Wind speed animations

File Naming Convention

The video creation functions expect PNG files to follow this naming pattern:

  • velocity_reduction_t0000s.png
  • velocity_reduction_t0012s.png
  • wind_speed_t0024s.png
  • etc.

Output videos are named:

  • velocity_reduction_animation.mp4
  • added_turbulence_animation.mp4
  • wind_speed_animation.mp4

Tips

  1. Frame Rate: Start with low FPS (2-4) for overview videos, use higher FPS (8-12) for detailed analysis
  2. Storage: Use delete_frames=true to save disk space after video creation
  3. Quality: Videos are created with good quality settings (CRF 23) suitable for presentations
  4. Troubleshooting: If video creation fails, check that FFmpeg is installed and PNG files exist

Integration with main.jl

The example main.jl includes video creation as PLT option 7:

# Set PLT=7 to create videos from saved frames
PLT = 7
include("examples/main.jl")