gource-visualizer

Gource Visualizer

Gource is an open-source software version control visualization tool that renders repository history as an animated tree. This skill orchestrates the full pipeline from installation through rendering, producing MP4 or WebM video files, PNG thumbnails, and render summary reports. It activates when a user wants to visualize repository history, create a code evolution video, generate a Gource animation, see project timelines, or says "show me what we built."

All script paths below are relative to skills/gource-visualizer/.

Quick Start

The 80% case: a single git repository, one video output.

1. Install dependencies (idempotent -- skips if already present):

``bash bash scripts/install-gource.sh ``

1. Detect repository metrics -- captures commit count, contributors, date range as JSON:

``bash bash scripts/detect-repo.sh <repo-path> ``

1. Select a preset based on user intent (default: standard):
2. "quick look" / "preview" --> quick
3. "presentation" / "demo" --> standard
4. "publication" / "YouTube" / "portfolio" --> cinematic
5. "thumbnail" / "screenshot" --> thumbnail

1. Render the video:

``bash bash scripts/render-video.sh --repo <repo-path> --preset standard --output <output-dir>/video.mp4 ` The render script auto-calculates --seconds-per-day from repository metrics and preset target duration. It auto-detects headless environments and delegates to scripts/render-headless.sh` when no display is available.

1. Deliver output to the user with a summary: video file path, duration, resolution, file size, repository metrics (commits, contributors, date range).

Decision Tree

Route user intent through this tree to select the right workflow path.

User wants a visualization
  |
  +-- Single repo in current directory?
  |   +-- Yes --> Quick Start path (above)
  |   +-- No  --> Ask which repo, or detect workspace repos
  |
  +-- Multiple repos mentioned?
  |   +-- Yes --> Multi-Repository Workflow (below)
  |
  +-- Specific time range mentioned?
  |   +-- Yes --> Add --start-date YYYY-MM-DD --stop-date YYYY-MM-DD
  |
  +-- Quality or purpose mentioned?
  |   +-- "quick look" / "preview"              --> preset: quick
  |   +-- "presentation" / "demo"               --> preset: standard
  |   +-- "publication" / "YouTube" / "portfolio" --> preset: cinematic
  |   +-- "thumbnail" / "screenshot"            --> preset: thumbnail
  |
  +-- No display / CI / server environment?
      +-- Auto-detected by render-video.sh; --headless flag added automatically

Multi-Repository Workflow

Combine multiple repositories into a single visualization with namespace prefixing and optional per-repo color coding.

1. Collect repository paths from the user.
2. Merge logs with color coding:

``bash bash scripts/merge-repos.sh --color --output combined.log <repo1> <repo2> ... ``

1. Render the combined log:

``bash bash scripts/render-video.sh --repo combined.log --preset <preset> --output <output-dir>/video.mp4 ``

For detailed multi-repo configuration (namespace prefixing, color palette, chronological sorting), see references/multi-repo-guide.md.

Enhancement Options

Optional enhancements to add to any render command:

• Captions (milestone markers from git tags):

``bash bash scripts/generate-captions.sh <repo-path> captions.txt ` Then pass --caption-file captions.txt to render-video.sh`.

• Avatars (GitHub profile pictures for contributors):

``bash bash scripts/resolve-avatars.sh <repo-path> avatars/ ` Then pass --avatar-dir avatars/ to render-video.sh`.

• Logo overlay: --logo path/to/logo.png

• Title overlay: --title "Project Name"

• Custom time range: --start-date YYYY-MM-DD --stop-date YYYY-MM-DD

• WebM format: --format webm (VP9 codec instead of H.264)

• Audio track: Post-process with ffmpeg to add music (see references/ffmpeg-pipeline.md).

Preset Reference

| Preset | Resolution | FPS | Use Case | Target Duration | |--------|-----------|-----|----------|-----------------| | quick | 720p (1280x720) | 30 | Fast preview, iteration | ~30s | | standard | 1080p (1920x1080) | 60 | Presentations, demos | ~3 min | | cinematic | 1080p (1920x1080) | 60 | YouTube, portfolio, publication | ~4 min | | thumbnail | 1080p (1920x1080) | -- | Single frame capture | < 10s |

Preset configs are at configs/preset-<name>.conf. The render script auto-calculates --seconds-per-day to hit the target duration based on repository date range.

For preset customization and parameter details, see references/presets.md.

Reference Documents

| Reference | When to Read | Purpose | |-----------|-------------|---------| | references/installation-guide.md | Installation fails or platform-specific issues | Detailed platform install procedures (apt, brew, manual) | | references/presets.md | User wants to understand or customize presets | Preset breakdown, parameter tuning, config format | | references/ffmpeg-pipeline.md | Video encoding issues, format conversion, audio | Complete ffmpeg recipe book for post-processing | | references/multi-repo-guide.md | Combining multiple repositories | Step-by-step multi-repo workflow with examples | | references/custom-log-format.md | Non-git sources, manual log creation | Gource custom log format specification | | references/option-reference.md | Advanced customization beyond presets | Curated Gource option guide with examples |

Troubleshooting

| Symptom | Cause | Fix | |---------|-------|-----| | "could not initialize SDL" | No display / headless environment | Use --headless flag or scripts/render-headless.sh | | "Xvfb failed to start" | Xvfb not installed | sudo apt-get install xvfb | | Black or corrupt video | ffmpeg framerate mismatch | Ensure ffmpeg -r matches Gource --output-framerate in preset config | | No users visible | No commits in selected date range | Widen --start-date / --stop-date range | | Very fast or slow video | Auto-timing miscalculation | Override with explicit --seconds-per-day value | | "libx264 not found" | ffmpeg missing H.264 codec | sudo apt-get install libx264-dev or reinstall ffmpeg from package |

GSD Integration

When running under a GSD workflow, output files go to the GSD output directory. The render summary includes: video path, duration, resolution, repo metrics, and contributor count.

For post-milestone visualization, read the milestone's git tag range to set --start-date and --stop-date, producing a video that covers exactly that milestone's development period.

The skill works with the gource-visualizer agent pipeline (see agents/ directory) for fully automated multi-step workflows including installation, detection, rendering, and delivery.

Script Inventory

| Script | Purpose | |--------|---------| | scripts/install-gource.sh | Idempotent installer for Gource, ffmpeg, Xvfb | | scripts/detect-repo.sh | VCS detection and metrics extraction (JSON output) | | scripts/generate-log.sh | Single-repo Gource custom log generation | | scripts/merge-repos.sh | Multi-repo log merge with namespacing and color | | scripts/generate-captions.sh | Git tags to Gource caption format | | scripts/resolve-avatars.sh | GitHub API avatar fetcher with caching | | scripts/render-video.sh | Gource-to-ffmpeg render pipeline orchestrator | | scripts/render-headless.sh | Xvfb wrapper for headless environments |