Importance of Downscaling

Elegant · 1st June 2015, 02:58

Hi, I have some anime blurays that are clearly upscaled. I've seen many posts comment about how upscales are bad all around, intended resolution of 540p (or less sometimes!), etc., but the real question comes down to what does downscaling get you? Is it just about the smaller file size? Is there some real reason I should be trying to to resize these videos down from 1080p to 720p or whatever resolution they were intended for? Or is it just the eyes of the beholder?

stax76 · 1st June 2015, 03:11

As with everything there are different requirements and opinions, an easy way to compare is StaxRip's comparison tool, it can be found in StaxRip's main menu at Tools/Advanced/Codec Comparison. It's a tool designed to compare video files with different codec and filter settings.

colours · 1st June 2015, 10:09

Quote:

Originally Posted by Elegant

Hi, I have some anime blurays that are clearly upscaled. I've seen many posts comment about how upscales are bad all around, intended resolution of 540p (or less sometimes!), etc., but the real question comes down to what does downscaling get you? Is it just about the smaller file size? Is there some real reason I should be trying to to resize these videos down from 1080p to 720p or whatever resolution they were intended for? Or is it just the eyes of the beholder?

Many posts where, and what are you making encodes of the Blu-rays for?

The primary advantage of downscaling things that were "clearly upscaled" is that, if the source was thoroughly damaged in the upscaling process (e.g. anything touched by Q-TEC), downscaling would help to conceal the upscaling artifacts, and in some cases, it also makes filtering said artifacts easier.

foxyshadis · 1st June 2015, 13:41

If you're using x264, it's a significant advantage just scaling down, because the DCT is so small (4x4 and 8x8) that fake information still needs real bits to encode. It's not nearly as useful for x265, where blocks have up to 4 times the size and the redundant information is more easily ignored. If it's been over-sharpened, though, all bets are off.

Some upscales are done well enough that they hold up for at least 720p; you'll have to do some comparisons of various downscales to figure out what the real resolution of the Blu-ray is. A script where you interleave the original with multiple downscale->upscale versions should quickly give you an idea of where the limit is, and from there you can decide how to encode it.

Elegant · 2nd June 2015, 15:23

@stax76 I'll have to check your tools out; I've been a user of MeGUI so far.

@colours I'm making encodes for a personal collection. These posts are from reviews of the blurays (Shakugan no Shana, Tsubasa Reservoir Chronicles) as well as common posts about how most early to mid 2000s anime are upscales on bluray and done poorly.

@foxyshadis I'll be sticking to x264 this go around I think since I'm not too familiar with x265 (that and MeGUI hated it so maybe I should try it with stax76's tool?). By sticking with x264 though you're saying it's best to downscale in this scenario. I'll look at stax76's tools real quick before I make an interleave script and find the "optimal" resolution.

colours · 2nd June 2015, 17:26

I've seen some screenshots comparing the Blu-ray and DVD releases of the first season of Shana, and the DVD release had far better video quality because of all the horrible postprocessing done for the BD masters. I don't know how good/bad the BDs for the second season of Shana or Tsubasa Reservoir Chronicles look, though.

In general, the downscale-upscale method of determining the "native" resolution of a source only really works when it's been upscaled with a simple resizer, which is not the case with the botched BD releases done by Q-TEC et al. In your case, it's (probably) safe to guess that the shows were produced in standard definition, so if getting the DVDs is not an option, you should resize to 480p.

foxyshadis · 3rd June 2015, 11:41

I wonder if the masters were just thrown away when production finished? I've come across so many early digitally produced anime where the DVDs were significantly better than the Blu-ray.

/Still hoping for a Kimagure Orange Road BD, hoping the film stock still exists.

Motenai Yoda · 3rd June 2015, 21:22

As I experienced often "original" resolution isn't 540p or 960p but also non-standard resolutions ie like 1366x680 or 1600x900...
The only way is to try until artefacts as aliasing or gibbs disappear.

1st June 2015, 02:58	#1 \| Link
Elegant Registered User Join Date: Jul 2014 Posts: 55	Importance of Downscaling Hi, I have some anime blurays that are clearly upscaled. I've seen many posts comment about how upscales are bad all around, intended resolution of 540p (or less sometimes!), etc., but the real question comes down to what does downscaling get you? Is it just about the smaller file size? Is there some real reason I should be trying to to resize these videos down from 1080p to 720p or whatever resolution they were intended for? Or is it just the eyes of the beholder?

2nd June 2015, 17:26	#6 \| Link
colours Registered User Join Date: Mar 2014 Posts: 308	I've seen some screenshots comparing the Blu-ray and DVD releases of the first season of Shana, and the DVD release had far better video quality because of all the horrible postprocessing done for the BD masters. I don't know how good/bad the BDs for the second season of Shana or Tsubasa Reservoir Chronicles look, though. In general, the downscale-upscale method of determining the "native" resolution of a source only really works when it's been upscaled with a simple resizer, which is not the case with the botched BD releases done by Q-TEC et al. In your case, it's (probably) safe to guess that the shows were produced in standard definition, so if getting the DVDs is not an option, you should resize to 480p. __________________ Say no to AviSynth 2.5.8 and DirectShowSource! Last edited by colours; 2nd June 2015 at 19:24.

3rd June 2015, 21:22	#8 \| Link
Motenai Yoda Registered User Join Date: Jan 2010 Posts: 709	As I experienced often "original" resolution isn't 540p or 960p but also non-standard resolutions ie like 1366x680 or 1600x900... The only way is to try until artefacts as aliasing or gibbs disappear. __________________ powered by Google Translator

1st June 2015, 03:11	#2 \| Link
stax76 Registered User Join Date: Jun 2002 Location: On thin ice Posts: 6,837	As with everything there are different requirements and opinions, an easy way to compare is StaxRip's comparison tool, it can be found in StaxRip's main menu at Tools/Advanced/Codec Comparison. It's a tool designed to compare video files with different codec and filter settings.

1st June 2015, 13:41	#4 \| Link
foxyshadis Angel of Night Join Date: Nov 2004 Location: Tangled in the silks Posts: 9,559	If you're using x264, it's a significant advantage just scaling down, because the DCT is so small (4x4 and 8x8) that fake information still needs real bits to encode. It's not nearly as useful for x265, where blocks have up to 4 times the size and the redundant information is more easily ignored. If it's been over-sharpened, though, all bets are off. Some upscales are done well enough that they hold up for at least 720p; you'll have to do some comparisons of various downscales to figure out what the real resolution of the Blu-ray is. A script where you interleave the original with multiple downscale->upscale versions should quickly give you an idea of where the limit is, and from there you can decide how to encode it.

2nd June 2015, 15:23	#5 \| Link
Elegant Registered User Join Date: Jul 2014 Posts: 55	@stax76 I'll have to check your tools out; I've been a user of MeGUI so far. @colours I'm making encodes for a personal collection. These posts are from reviews of the blurays (Shakugan no Shana, Tsubasa Reservoir Chronicles) as well as common posts about how most early to mid 2000s anime are upscales on bluray and done poorly. @foxyshadis I'll be sticking to x264 this go around I think since I'm not too familiar with x265 (that and MeGUI hated it so maybe I should try it with stax76's tool?). By sticking with x264 though you're saying it's best to downscale in this scenario. I'll look at stax76's tools real quick before I make an interleave script and find the "optimal" resolution.

3rd June 2015, 11:41	#7 \| Link
foxyshadis Angel of Night Join Date: Nov 2004 Location: Tangled in the silks Posts: 9,559	I wonder if the masters were just thrown away when production finished? I've come across so many early digitally produced anime where the DVDs were significantly better than the Blu-ray. /Still hoping for a Kimagure Orange Road BD, hoping the film stock still exists.