Video Analysis Workflow

Analysis Commands

CMJ analysis

uv run kinemotion cmj-analyze <video> [--output debug.mp4]

Drop Jump analysis

uv run kinemotion dropjump-analyze <video> [--output debug.mp4]

Batch processing

uv run kinemotion cmj-analyze videos/*.mp4 --batch --workers 4

Quality Presets

Preset Use Case Trade-off

fast

Quick preview, large batches Lower accuracy

balanced

Default, most use cases Good accuracy/speed

accurate

Validation, research Best accuracy, slower

uv run kinemotion cmj-analyze video.mp4 --quality accurate

Debug Output

Always use --output debug.mp4 when:

• Metrics seem incorrect

• Troubleshooting pose detection

• Validating new videos

• Training coaches on video quality

The debug video shows:

• Skeleton overlay with joint angles

• Phase markers (takeoff, landing, peak)

• Real-time metrics display

Camera Angle Recommendations

Angle Recommendation Reason

45° oblique Recommended Both legs clearly visible, accurate tracking

90° lateral Not recommended MediaPipe confuses left/right feet (occlusion)

Front/back Not recommended Depth ambiguity for sagittal plane motion

Troubleshooting

No Takeoff Detected

• Verify video contains complete jump (before, during, after)

• Check athlete is fully visible throughout

• Try --quality accurate for stricter detection

• Review debug video for landmark quality

Invalid Metrics

• Video may be too short (need full jump cycle)

• Athlete may be partially occluded

• Poor lighting affecting pose detection

• Camera shake causing landmark jitter

Jittery Landmarks

• Check lighting conditions (avoid backlighting)

• Ensure stable camera (tripod recommended)

• Verify athlete clothing contrast with background

• Try --quality accurate for better filtering

Rotation Issues (Mobile Videos)

• Mobile videos often have rotation metadata

• kinemotion handles this automatically via video_io.py

• If issues persist, pre-process with: ffmpeg -i input.mp4 -vf "transpose=1" output.mp4

Video Requirements

Requirement Specification

Frame rate 30+ fps (60+ preferred)

Resolution 720p minimum

Duration Full jump cycle visible

Lighting Even, front-lit preferred

Background Contrasting with athlete

Camera Stable, tripod recommended

Output Metrics

CMJ Metrics

• jump_height_cm : Calculated from flight time

• flight_time_ms : Time in air

• countermovement_depth_cm : Lowest point before takeoff

• takeoff_velocity_m_s : Velocity at ground leave

• triple_extension : Hip, knee, ankle angles at takeoff

Drop Jump Metrics

• ground_contact_time_ms : Time on ground after drop

• flight_time_ms : Time in air after contact

• reactive_strength_index : RSI = flight_time / contact_time

• drop_height_cm : Initial drop height (if detectable)

Python API Alternative

from kinemotion import process_cmj_video, process_dropjump_video

CMJ

metrics = process_cmj_video("video.mp4", quality="balanced")

Drop Jump

metrics = process_dropjump_video("video.mp4", quality="balanced")