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To: enumerated
said, "soft borders (blurry edges) and non-homogenous textures can cause an area to be selectively compressed - causing it to be temporarily “disappear”"

As I pointed out earlier. This is done with MRI brain scans which the MRI program needs to be modified for this layered effect. There is no case like this on normal cameras.

290 posted on 03/18/2021 1:32:14 PM PDT by Steve Van Doorn (*in my best Eric Cartman voice* 'I love you, guys')
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To: Steve Van Doorn

MRI? Brain-scans? I’m not talking about any of that - I’m talking about normal video recordings.

I’m talking about temporal compression artifacts from normal video recordings.

In simple terms, in order to reduce the amount of image data stored for each frame, the compression software attempts to take areas of uniform or near uniform rgb color value - say a large area of white - and rather than store the rgb color value of 10k individual pixels for that area, it will define the area’s pixel range by rows and columns, and assign one rgb color value (white) to the entire range.

The compression software then decides whether there is enough of a change from frame to frame in a given pixel area to justify re-testing and assigning new color value to pixels and pixel areas.

The larger the bandwidth, the larger the data file is allowed to be, and the less compression there is - and the more accurate the playback.

The more limited the bandwidth, the smaller the data file is allowed to be, and the more compression there is - the less accurate the playback - you start to get weird artifacts - background pixels being left for the next frame when they should have been replaced by new pixels.

Pixels not being refreshed can create all sorts of spacial and temporal artifacts that make an object that was supposed to be covered by another object still visible.

Everything about that first video can be explained by data compression.


291 posted on 03/18/2021 2:37:13 PM PDT by enumerated
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