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name: "video-and-tracking" description: "Run 3DDFA_V2 video, smoothing, and manual webcam tracking workflows." metadata: disco-role: operating disable-model-invocation: true license: MIT

Video and tracking

Use this sub-skill for 3DDFA_V2 video-file processing and smoothing. Webcam support exists in the source repo but remains a manual, hardware-dependent workflow.

When to read

Read this sub-skill when the task asks to:

• Run demo_video.py or demo_video_smooth.py on an AVI/MP4 file.
• Produce tracked 2d_sparse, 2d_dense, or 3d video outputs.
• Tune n_pre, n_next, start, or end frame-window settings.
• Diagnose imageio, ffmpeg, tracking drift, or webcam/display issues.

Before running

1. Build and smoke-test the checkout with ../setup-and-assets/.
2. Confirm imageio and imageio-ffmpeg are installed.
3. Start with the sample clip if the user's input format is uncertain.

Basic video wrapper

The basic wrapper preserves the original demo_video.py CLI. Put original arguments after --:

python <skill-root>/sub-skills/video-and-tracking/scripts/run-video.py \
  --repo-root <checkout> -- \
  -f <video-path> -o 3d --onnx

Smoothed video wrapper

The smoothed wrapper preserves the original demo_video_smooth.py CLI:

python <skill-root>/sub-skills/video-and-tracking/scripts/run-video-smooth.py \
  --repo-root <checkout> -- \
  -f <video-path> -o 2d_sparse -n_pre 1 -n_next 1 --onnx

Tracking behavior

• The first frame uses detection; later frames track from the previous landmark state.
• If the ROI area becomes too small, the demo re-runs face detection.
• Motion that is too fast or head pose beyond roughly 90 degrees can make the lightweight tracker fail.
• Smoothing uses a simple average over n_pre + n_next + 1 frames and drops or pads boundary frames.

Webcam boundary

The repo has a webcam script that uses imageio.get_reader("<video0>") and cv2.imshow. This skill documents the workflow in references/workflows.md, but does not provide an automated webcam wrapper because it needs live camera hardware, GUI display access, and manual quit handling.

Troubleshooting

Read references/troubleshooting.md for video-specific failure recovery and ../../references/troubleshooting.md for shared build/import failures.