This is doc much required for archival, understanding what is a result of errors of recording onto media, physical damage on the media to errors of capture and software decoding visually knowing what your looking at is key to getting the best possible results out of any media preservation or analysis.

Inside ld-analyse do CTRL+S to save the current frame as a PNG file, this will save what's displayed, we use the luma channel only for error examples mostly, but errors are more variable for colour as it has to interact with the chroma-decoder, and a fully decoded to video file colour image should be made before calling it an actual error.

This is achieved there are little to no errors in the top VBI area or the active picture area, and the lines are consistent with each other.

(Inspector Gadget 1999 - With Macrovison & Closed Captions)

This is where the image is skewed, fields are miss-alined, and there is lots of grainy noise in the image.

This is a simulated image from a 40msps source, down-sampled RF data can result in loss of key signal information and result in issues like this.

When a heavy signal loss occurs this is called "snowing" as it's similar to looking at a snowstorm through a window.

Note the white line is harder than a normal dropout.

These are dropouts or hard information loss on the physical tape, assuming there is no video head damage.

Small

Medium

Large

LaserDisc

Dropouts are normally due to disc rot and are normally hard black.

More common on NTSC Media

This is a very fine pattern to notice in motion very apparent on digital displays.

Chroma-Decoded Colour

Luma TBC Image

Note: This capture has the head switch position moved into the H-Sync area.

ac3-mission00-sync-error.mp4

ac3-sample-level_detect_divisor6.mp4

Compendium Of Image Errors In Analouge Video / Kompendium Der Bildstorungen Beim Analogen Video 2012 - ISBN 978-3-85861-381-7

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