H.264 is Magic

Post by danieltillett » Sat, Nov 05, 2016, 5:34 AM UTC

Animats wrote: post #166

erydo wrote: post #91

Earlier quoted context omitted.

Your example seems to assume translation only. I wonder how difficult/useful it would be to identify other kinds of time-varying characteristics (translation, rotation, scale, hue, saturation, brightness, etc) of partial scene elements in an automated way. Along the same lines, it would be interesting to figure out an automated time-varying-feature detection algorithm to determine which kinds of transforms are the ri…

I wonder how difficult/useful it would be to identify other kinds of time-varying characteristics (translation, rotation, scale, hue, saturation, brightness, etc) of partial scene elements in an automated way. That's how Framefree worked. It segments the image into layers, computes a full morph, including movement of the boundary, between successive frames for each layer, and transmits the before and after for each m…

Post by rahkiin » Sat, Nov 05, 2016, 8:12 AM UTC

noisem4ker wrote: post #30

logicallee wrote: post #24

Earlier quoted context omitted.

This is really interesting and the imgur picture you linked (with your explanation) explains it really clearly! But when seeking, why wouldn't any local media playback seek backwards and reconstruct the full frame? It's not like the partial frame after seeking is useful - I'd rather wait 2 seconds while it scrambles (i mean "hurries up") to show me a proper seek, wouldn't everyone? What was your Internet search for f…

>why wouldn't any local media playback seek backwards and reconstruct the full frame? Most codecs/players do. VLC used to be criticized for being different in that regard. One possible advantage is istantaneous seeking, as there's no need to decode all the needed frames (which could amount to several seconds of video) between the nearest I-frames[1] (the complete reference pictures) and the desired one. [1]: plural,…

Post by amelius » Sat, Nov 05, 2016, 10:04 AM UTC

LordDragonfang wrote: post #137

amelius wrote: post #4

> discard information which will contain the information with high frequency components. Now if you convert back to your regular x-y coordinates, you'll find that the resulting image looks similar to the original but has lost some of the fine details. I would expect also the edges in the image to become more blurred, as edges correspond to high-frequency content. However, this only seems to be slightly the case in th…

You can see exactly that with the speaker grill and the text (This type of transformation is notoriously bad at compressing images of text, and is why you shouldn't use jpg for pictures of text) In this context, the edges of, say, the macbook are not "high frequency" content, since they only feature one change (low to high luminosity) in a given block rather than several (high-low-high-low-high) like for the grill.

Post by umbs » Sat, Nov 05, 2016, 11:53 AM UTC

Post by xyproto » Sat, Nov 05, 2016, 12:44 PM UTC