time to move on H.265
H.264 is Magic
161–170 of 230 posts
Re: H.264 is Magic
#162time to move on: h.265
Re: H.264 is Magic
#163Earlier 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…
Now I'm out of my depth, but I think motion compensation does okay at rotation and scaling. The motion vector varies throughout the frame, and I think codecs interpolate it, so all kinds of warping can be represented.
As evidence of this, sometimes when an I-frame is dropped from a stream or you jump around in a stream you can see the texture of what was previously on the screen wrapped convincingly around the 3D surface of what's now supposed to be on the screen, all accomplished with 2D motion vectors.
Re: H.264 is Magic
#164time to make move on: h.265
Re: H.264 is Magic
#165So what's the final car weight? It looks like you stopped at the Chroma subsampling section..
6.5 Ounces! or 0.4 lbs. Thanks for the feedback! I added the final weight into the conclusion.
Re: H.264 is Magic
#166Nice article! The motion compensation bit could be improved, though: > The only thing moving really is the ball. What if you could just have one static image of everything on the background, and then one moving image of just the ball. Wouldn't that save a lot of space? You see where I am going with this? Get it? See where I am going? Motion estimation? Reusing the background isn't motion compensation -- you get that…
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 morph. Any number of frames can be interpolated between keyframes, which allows for infinite slow motion without jerk.[1] You can also upgrade existing content to higher frame rates.
This was developed back in 2006 by the Kerner Optical spinoff of Lucasfilm.[2] It didn't catch on, partly because decompression and playback requires a reasonably good GPU, and partly because Kerner Optical went bust. The segment-into-layers technology was repurposed for making 3D movies out of 2D movies, and the compression product was dropped. There was a Windows application and a browser plug-in. The marketing was misdirected - somehow, it was targeted to digital signs with limited memory, a tiny niche.
It's an idea worth revisiting. Segmentation algorithms have improved since 2006. Everything down to midrange phones now has a GPU capable of warping a texture. And it provides a way to drive a 120FPS display from 24/30 FPS content.
[1] http://creativepro.com/framefree-technologies-launches-world... [2] https://web.archive.org/web/20081216024454/http://www.framef...
Re: H.264 is Magic
#167[deleted]
Excuse me, i would like my account back.
Re: H.264 is Magic
#168Absolutely love this: 'Suppose you have some strange coin - you've tossed it 10 times, and every time it lands on heads. How would you describe this information to someone? You wouldn't say HHHHHHHHH. You would just say "10 tosses, all heads" - bam! You've just compressed some data! Easy. I saved you hours of mindfuck lectures.' This is a really great, simple way to explain what is otherwise a fairly complex concept…
I would probably say I found a two headed coin. I also like how "HHHHHHHHHH" is shorter than "I tossed it 10 times, all heads"
Re: H.264 is Magic
#169Nice article! The motion compensation bit could be improved, though: > The only thing moving really is the ball. What if you could just have one static image of everything on the background, and then one moving image of just the ball. Wouldn't that save a lot of space? You see where I am going with this? Get it? See where I am going? Motion estimation? Reusing the background isn't motion compensation -- you get that…
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…
Yes, H.264 has brightness/fade compensation for past frames. It's called "weighted prediction".
The previous codec MPEG4 part 2 ASP (aka DivX&XviD) had "global motion compensation" which could encode scales and rotation, but like most things in that codec it was broken in practice. Most very clever ideas in compression either take too many bits to describe or can't be done in hardware.
Re: H.264 is Magic
#170> Chroma Subsampling. Sadly, this is what makes video encoders designed for photographic content unsuitable for transferring text or computer graphics. Fine edges, especially red-black contrasts start to color-bleed due to subsampling. While a 4:4:4 profile exists a lot of codecs either don't implement it or the software using them does not expose that option. This is especially bad when used for screencasting. Anoth…
It's easy to make a 4:2:0 upscaler that doesn't color bleed. Everyone just uses nearest-neighbor, which sucks, and then blames the other guy.