This skill should be used when the user asks "compare these videos", "which source is better", "compare blu-ray vs web", "which release should I use", "compare video quality", or needs to evaluate multiple versions of the same content to determine which has better quality.
Compare multiple video sources to determine which has better quality. Higher bitrate or resolution does not automatically mean better quality.
Quality = how closely video resembles original master.
When comparing sources:
Run MediaInfo on both sources:
mediainfo source_a.mkv > source_a_info.txt
mediainfo source_b.mkv > source_b_info.txt
Compare:
Note: Higher numbers don't guarantee better quality.
Choose frames that reveal quality differences:
Good comparison frames:
Extract frames with ffmpeg:
# Extract frame at specific timestamp
ffmpeg -ss 00:15:30 -i source.mkv -frames:v 1 frame_15m30s.png
# Extract multiple frames
ffmpeg -ss 00:10:00 -i source.mkv -frames:v 1 frame1.png
ffmpeg -ss 00:25:00 -i source.mkv -frames:v 1 frame2.png
ffmpeg -ss 00:45:00 -i source.mkv -frames:v 1 frame3.png
Using SlowPics (https://slow.pics):
What to look for:
| Area | Better Source Shows |
|---|---|
| Dark gradients | Smoother transitions, less banding |
| Edges | Clean edges, no haloing/ringing |
| Textures | Preserved grain/detail, not smeared |
| Colors | Natural, not oversaturated or shifted |
| Compression | Less blocking, less mosquito noise |
Signs of harmful filtering:
Lowpassing (blur):
Sharpening:
Color manipulation:
Upscaling:
Blu-ray usually better when:
Web can be better when:
Different authoring studios, regions, or editions can have different quality:
HD version better when:
SD version better when:
Higher bitrate source might be worse if:
Higher resolution source might be worse if:
| Comparison | Check First | Likely Winner |
|---|---|---|
| Blu-ray vs Web | Filtering, authoring | Depends on studio |
| 4K vs 1080p | Native resolution | If native, 4K |
| HEVC vs AVC | Encoder, settings | Neither inherently |
| High vs low bitrate | Encoder efficiency | Higher if same encoder |
| HDR vs SDR | HDR legitimacy | SDR if HDR is fake |
${CLAUDE_PLUGIN_ROOT}/references/quality-myths.md - Why specs don't equal quality${CLAUDE_PLUGIN_ROOT}/references/artifacts.md - What quality issues look like