480p for 16:9 is 853.33x480. right?
Since a pixel should be a whole number, ppl use 854 or 852 or 848 for width.
Ppl use 852x480 to get the width dividable by 4.
And 848x480 to it dividable by 16.
I would like to know how HEVC behaves among those 3 resolution. (854x480, 852x480, 848x480)
Sure it supports all 3... But what are the impacts of encoding...
Regarding the resolution factors and image stretch and A/R deviations when resizing, what could be the optimal for HEVC
In HEVC, is that, dividable by 4 and 16 factors are less important than in AVC?
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There should be no "humanly-perceivable" differences between 852x480 and 854x480.
Aa for the mod16 restrictions... they should be regarded as 'outdated' stuff.
I would not buy a standalone player whose firmware cannot deal with mod8, mod4 and mod2 videos.
Strictly speaking, even MPEG-1 and MPEG-2 *encoding* requires only mod8 frame dimensions.
MPEG-4 ASP requires just mod2 (or mod4, if the content is interlaced). Same rule applies to AVC.
Last edited by El Heggunte; 27th Sep 2015 at 22:14. Reason: grammar
- My sister Ann's brother
In fact, usually encoders expand the video to the next supported modulo dimension by mirroring or repeating content at a border, and store a "crop area" to tell the decoder to omit encoded material beyond this rectangle. A famous example is 1080 video which is usually encoded with a height of 1088 lines. Speedwise it may be only a small penalty, but the efficiency won't be optimal here.
There are some Android TV boxes that can hardware decode HEVC, and I know some 2015 model Samsung smart TVs can play HEVC. (My mother's new TV does, but I have only tested it with one file so far.)
However, I'm not sure playback with something other than a computer is much of a consideration at present. I think at this point, most people who a own stand-alone or built-in media player (in a TV, or Blu-Ray player) have one that doesn't play HEVC.
As for the encoders... please name them.
Mainconcept Reference, DivX VfW, Xvid, x264, x265, HCenc, TMPGenc, wvc1enc, are the ones that I use.
None of them refuses to encode to non-mod16 dimensions
You could be right all around, but maybe you should keep your day job for now and hold off on looking for those professional video processing jobs until later.
iTunes video. Much of it has dimensions such as 1276x718 etc. If mod restrictions were a common playback problem, I imagine iTunes would make sure they're not constantly receiving complaints.
If a DVD is exactly 16:9 and there's no cropping required, the resizing which produces the least aspect ratio distortion is 852x480, although it does require the cropping of a single pixel from one side. Which you can do with Avisynth's resizers:
I did some x264 encoding testing at one stage, encoding using different mods, with and without black borders etc, and it all makes so little difference to the bitrate it's not really a factor there. Playback isn't an issue. I've not met a player that won't play h264 video because it's mod4 or mod2. I can't imagine h265 being any different. Personally I stick to mod4 widths and mod2 heights, mod4 widths being mainly due to Windows and DirectShow sometimes having problems with mod2 widths, but that's just a case of paranoia on my part. Modern software players don't care, and likewise neither do hardware players, in my experience.
Below Thread Says that it is better if the mod 2 is just below the upper mod16.
[Not related to this, but it says that 862x480 will be better than others like 852x480. (Here it makes A/R related issues). Mod2 closer to the below mod16 is the worst]
It might help when cropping blu-rays... 1038 mod2 will be better than 1036 mod4. Since it is height, mod2 will be safe.
But the question is with widths!