Posted: 12/15/2010 9:55 PM
Post subject: Question about HD encodes: Why?
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fruitbane
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Joined: 3/28/2005
Posts: 216
This may seem obvious to some, but not to me. Why do we do HD encodes at high resolutions for games with very low resolutions? If some kind of filter is applied I understand (like PSX, Sat, and N64 encodes), but if there's no filtering of the output the pixels just get larger. To me, it seems like an encode at the closest resolution equal to or higher than the original output would be best. Maybe someone can offer me a perspective on this that will open my eyes a little.
Posted: 12/15/2010 9:59 PM
(Edited: 12/15/2010 10:26 PM)
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GabCM
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Joined: 5/5/2009
Posts: 901
Location: QC, Canada
YouTube and a lot of video players can't resize videos properly. In fact, they are only able to make them smaller. When they are trying to make them bigger, it looks blurry, which is bad. So, we make HD encodes to make sure that even if you watch the video in full screen, it still looks sharp! Personnaly, I only do these encodes for YouTube. I've made a comparison picture to show you what I mean. And it's only when using the big YouTube player! Imagine that SD mess in fullscreen.
Posted: 12/15/2010 10:11 PM
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mmarks
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Joined: 8/30/2010
Posts: 500
Location: Argentina Bs. As.
Yes, I agree with Mister Epic, if make we encodings in SD, are useful and required to do. But coding in HD the image or video, is of great quality and great resolution. What made this page, since such year, be make this encodings of good resolution and quality
[18:51] <scrimpy> Oh, nothing [18:51] <mmarks> oh [18:51] <Nach> I think scrimpy is just jealous of you mmarks
Posted: 12/15/2010 10:12 PM
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Aktan
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Joined: 4/23/2009
Posts: 1283
As Mister Epic said, that's only his personal preference. The real reason that HD videos popped up was due to YouTube being very crappy in quality. Upping the resolution was so that the video gets more bitrate and hence less quality loss. The other minor reason is there is less loss of colors due to the YV12 colorspace. Basically, due to the codec we use, the color information is lost (around 1/4th the original). Since this is pixel art, it is usually very noticeable. A simple fix to this would be a 2x resize, but obviously a bigger than 2x resize can also fix this. On a side note, I've noticed YouTube has up the quality on lower resolutions recently, maybe HD encoding isn't needed anymore. Also, I personally see HD encoding as useless.
Posted: 12/15/2010 10:20 PM
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GabCM
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Joined: 5/5/2009
Posts: 901
Location: QC, Canada
Aktan wrote:
On a side note, I've noticed YouTube has up the quality on lower resolutions recently, maybe HD encoding isn't needed anymore.
That would be something to check, since those screenshots were made a couple weeks ago.
Posted: 12/16/2010 10:32 AM
Post subject: Re: Question about HD encodes: Why?
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Warp
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Joined: 3/10/2004
Posts: 7698
Location: Finland
fruitbane wrote:
Maybe someone can offer me a perspective on this that will open my eyes a little.
Don't listen to them. The real reason is this.
Posted: 12/16/2010 8:46 PM
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feos
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When we encode with cromoresample we get 1-pixel-thick artefacts. If the picture was not resized, they make a certain % of picture destroyed. But when we resample AFTER resizing - the % of picture destroyed lessens. Also, as 1 or 2 pixel wide objects look like crap in SD, in HD only a small part of them is destroyed.
Warning: When making decisions, I try to collect as much data as possible before actually deciding. I try to abstract away and see the principles behind real world events and people's opinions. I try to generalize them and turn into something clear and reusable. I hate depending on unpredictable and having to make lottery guesses. Any problem can be solved by systems thinking and acting.
Posted: 12/16/2010 8:48 PM
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Aktan
Publisher
Joined: 4/23/2009
Posts: 1283
feos wrote:
When we encode with cromoresample we get 1-pixel-thick artefacts. If the picture was not resized, they make a certain % of picture destroyed. But when we resample AFTER resizing - the % of picture destroyed lessens. Also, as 1 or 2 pixel wide objects look like crap in SD, in HD only a small part of them is destroyed.
That's what I explained above, but you don't need HD resolution to fix this. Just a resize of 2x in both directions already fixes the chroma problem.
Posted: 12/17/2010 3:06 AM
Post subject: Re: Question about HD encodes: Why?
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Flygon
Joined: 11/4/2007
Posts: 1772
Location: Australia, Victoria
Warp wrote:
fruitbane wrote:
Maybe someone can offer me a perspective on this that will open my eyes a little.
Don't listen to them. The real reason is this.
I'll work on surround sound when YouTube supports it.
Posted: 12/17/2010 10:10 AM
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feos
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Flygon Even for games that output only 1 channel? ;)
Warning: When making decisions, I try to collect as much data as possible before actually deciding. I try to abstract away and see the principles behind real world events and people's opinions. I try to generalize them and turn into something clear and reusable. I hate depending on unpredictable and having to make lottery guesses. Any problem can be solved by systems thinking and acting.
Posted: 12/17/2010 11:54 AM
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Flygon
Joined: 11/4/2007
Posts: 1772
Location: Australia, Victoria
feos wrote:
Flygon Even for games that output only 1 channel? ;)
Especially games with only one channel of output.
Posted: 12/17/2010 4:07 PM
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nfq
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Joined: 5/10/2005
Posts: 1204
I think the SD quality looks better because it's blurrier... it's like an interpolation filter.
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