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killadark
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Encoding help for noob :P

Thu Dec 18, 2014 4:33 pm

So i recently found out that handbrake has the x265 so jus for trying it out i kept one of my raw anime episode for encoding over night....
I WAS AMAZED by how little size it took up while looking pretty much looking the same :D
Quality of the video was great i did notice it being a bit brighter as if the color tone had gotten saturated i think, any idea why that happens?

it went from 4.7gb to a mere 670mb

now there are a few option in handbrake i have no idea what they mean, i have looked around the web for tutorials for x265 but there are none and everything in x265 related is gibberish to me.

what does the x265 Tune do? psnr,ssim
What does the h.265 profile do? main,main10
Does encoding slower give better quality and size?

i use RF of 18 for Encoding
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meerkt
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Re: Encoding help for noob :P

Thu Dec 18, 2014 7:02 pm

Profiles in video encoders limit the encoding options/features that can be used. It's to assure compatibility with decoders that don't support all features or have other limitations. More here: http://en.wikipedia.org/wiki/High_Effic ... g#Profiles

Better encodes will usually take longer than lower-quality ones. But it depends on your settings, some compute intensive options matter more than others. And beyond a certain point it's diminishing returns.

But I'm not sure x265 gives better results yet than x264, and it's definitely less compatible for the time being.

One of the better forums for technical video discussion is Doom9. Here's a random related thread: http://forum.doom9.org/showthread.php?t=171201
 
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Re: Encoding help for noob :P

Thu Dec 18, 2014 7:32 pm

x265 and x264 settings that you asked about will be similar so i put in both (also because i wrote out x264 settings first and im leaving them in anyways in case someone wants to know)

x264 tune is to adjust the encoding for what type of video you are encoding

the "tune" option tunes the encode depending on what you are encoding
choosing grain will help smooth out filmgrain so it will be less noticable
choosing animation will make it recognize that the content will be more "simple" giving you the option to get better compression
psnr/ssim is used to compare one encode to another its like a benchmark for quality, it will give you a number of how close the encode is to the original - you really shouldnt worry about this one until you understand how everything else works

the "profile" option sets the encode settings depending on the device you want to play it on and also the quality of the final encode
devices like phones/tablets etc have a certain "profile" they are able to play videos at and if you go over the settings for the profile the device is capable of then you will experience problems like stuttering or it might even refuse to play it
, if you are using the encoded video on your pc only then you can go to the highest profile or go custom and max out all the settings the profile settin changes if you like - but if you are planning to use it on just about anything else its best to stick to the profile the device is capable of
for example the iphone 5 has a maximum profile of 4.1 high profile

decoding slower can give you a better image and file size but beyond a certain point its what they call a "placebo" setting and wont change the quality much if at all
on the "preset" slider i would recommend going "slower" or "very slow" if you want good file sizes and quality video - placebo is pretty much just that, a placebo - lower quality presets does make a noticeable difference in quality and file size imo


personally i go full custom settings that are close to placebo settings so i can "maybe" get better file size/quality


DAMN i got all the way through that and i just realized the settings are different for x265 but the explanation is still the same imo
psnr and ssim will be for giving you a number that relates to the quality of the video compared to the original (so it isnt really needed imo and i would go none)
profile will be to set certain profiles with "limits" for certain devices that are playing back the video, main seems to be the first profile released for the spec and main10 seems to be for 10bit color video - imo unless you have a 10bit source use main or none
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just brew it!
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Re: Encoding help for noob :P

Thu Dec 18, 2014 11:57 pm

Sorry for the semi-hijack, but speaking of noob encoding questions... does anyone know why a lot of compressed video streams exhibit really horrible pixelation in red areas of the image, even if other colors look decent? It's something I've been noticing for a few years, but I've never found a good explanation (in spite of searching for one).
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Chrispy_
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Re: Encoding help for noob :P

Fri Dec 19, 2014 7:20 am

just brew it! wrote:
Sorry for the semi-hijack, but speaking of noob encoding questions... does anyone know why a lot of compressed video streams exhibit really horrible pixelation in red areas of the image, even if other colors look decent? It's something I've been noticing for a few years, but I've never found a good explanation (in spite of searching for one).


I've never noticed this. Do you have any 16-232 -> 0-255 filters running, or is your monitor calibrated in such a way that red gradients are (by necessity) non-linear?
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killadark
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Re: Encoding help for noob :P

Fri Dec 19, 2014 8:30 am

well thanks for the replies i think i understand a bit more on how it works :)
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Re: Encoding help for noob :P

Fri Dec 19, 2014 5:22 pm

just brew it! wrote:
Sorry for the semi-hijack, but speaking of noob encoding questions... does anyone know why a lot of compressed video streams exhibit really horrible pixelation in red areas of the image, even if other colors look decent? It's something I've been noticing for a few years, but I've never found a good explanation (in spite of searching for one).

do you have an example screenshot of this?
its not something i have noticed myself and im very picky with my encodes
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meerkt
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Re: Encoding help for noob :P

Fri Dec 19, 2014 7:16 pm

just brew it! wrote:
does anyone know why a lot of compressed video streams exhibit really horrible pixelation in red areas of the image, even if other colors look decent?
It's also other colors, I believe. I'm not fully sure why red hues end up exhibiting it more (will have to check some samples in detail), but it has to do with the fact that common video codecs store colors not as RGB but as YCbCr (1 luminance channel + 2 color channels, sometimes also called YUV), and only the luminance channel is stored at full resolution. The two color channels are commonly stored at half the horizontal and half the vertical resolution (http://en.wikipedia.org/wiki/Chroma_subsampling#4:2:0). I guess reds end up having less energy in the luma channel, which is the only one with full resolution.

On a quick look at the info here, it seems to me pure blues should be the worse colors, as B contributes the least to Y. But maybe pure/mostly pure reds just happen to be more common in movies.

You can improve the situation by making sure the player uses some smoothening filtering (bilinear, bicubic, etc.) to upscale the chroma channels, instead of just point sampling. Depending on how exactly the video is decoded, it could also be up to the graphics drivers.
 
Chrispy_
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Re: Encoding help for noob :P

Sun Dec 21, 2014 9:08 am

Can't say I've noticed the blue issue much. I'm a deuteranopic dichromat with (in theory*) 50% higher density of blue and red sensitive cones in my retinas than 99.4% of the population - and I can't see anything beyond the usual blocking in huge areas of similar colour.

Can you upload a screenshot? A picture speaks a thousand words etc...


* - there are some papers that suggest deuteranopic dicrhomats don't suffer from retinal density loss like deuteranomalous dichromats. Deuteranopic being a mutation of "only red and blue cones" rather than deuteranomoly being "green cones are present but ineffective". Increased sensitivity to UV blacklight for me and another dichromat I know seems to reinforce this although I've never seen a study on the effects, and we seem to be the first to spot "blueness" or "redness" at very low intensities or saturations, if the office printer output is anything to go by.
Last edited by Chrispy_ on Sun Dec 21, 2014 9:31 am, edited 1 time in total.
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just brew it!
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Re: Encoding help for noob :P

Sun Dec 21, 2014 9:15 am

Next time I notice it I will post a screenshot.
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