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January 27

Technical name for Video editing effect

In some parts of this Video, there are wavy screen cornering effect is done , is there any technical term for it? Rizosome (talk) 12:00, 27 January 2021 (UTC)[reply]

Could you link - or at least mention - a time frame? A watched a few seconds and clicked around a bit but didn't see anything. Watching en entire 13-minute copyright violated wrestling video is a bit of a large ask. Matt Deres (talk) 18:57, 27 January 2021 (UTC)[reply]

Around @1:16, @1:42, @2:12 of the video, right side of and @2:30 of the left side got deviated. Is there any technical term for this deviation? Rizosome (talk) 13:38, 28 January 2021 (UTC)[reply]

Radiojon Jeremy Butler TomCat4680 Mrschimpf Rizosome (talk) 14:41, 28 January 2021 (UTC)[reply]

I think it is an unintended artifact of digital image stabilization, performed in post-production to reduce the shakiness of the image, apparently taken with a handheld camera. To stabilize the image, the individual frames need to be shifted, which means some border pixels have to be sacrificed. In case of an extreme excursion, there is a choice: allow a bad image shake to remain, sacrifice an extreme number of border pixels in the adjacent frames, or shift without such sacrifice, but then fill in the missing pixels. In this case the software used the third option, but instead of using some combination of interpolating and extrapolating, it used black pixels as fillers. I expect that the digital image stabilization community has names for the most common approaches to this issue, but I don't know what they are. --Lambiam 14:55, 28 January 2021 (UTC)[reply]

January 28

Windows 10: Screen stays displayed all night

This is about Windows 10 on a desktop computer. The screen has stayed displayed all night for the last two nights. That is, if I leave the system alone, the display is still on eight hours later. I have the Power and Sleep options set for when plugged in, turn screen off after 5 minutes, and, when plugged in, PC goes to sleep after 2 hours. But it isn't turning the screen off and it isn't going to sleep. (Well, I am going to sleep, and I could theorize that it does turn the screen off when I am asleep, and then turns it back on when it sees me. But we won't engage in that speculation right now.) Until a few days ago it was behaving as expected. This behavior, staying on all night, is new. What might have happened to cause this? Robert McClenon (talk) 15:00, 28 January 2021 (UTC)[reply]

It depends a lot on the species of screen and also on the cable you use. Check that the screen itself is set to auto-sleep. You should have a menu option to set a specific delay and also to turn the overall function on/off — GhostInTheMachine ^{talk to me} 15:14, 28 January 2021 (UTC)[reply]

Do you have any tasks running that might tend to inhibit sleep? A video player, for example? Updates or a dialog box displayed? Elizium23 (talk) 16:50, 28 January 2021 (UTC)[reply]

Since this is new behaviour, my recommendation is to force it to restart once and see if that corrects the behaviour going forward. Matt Deres (talk) 14:51, 29 January 2021 (UTC)[reply]

I didn't do anything to change things, but it went to sleep last night, and the screen is switching off after 5 minutes. So whatever it was seems to have cleared up or resolved itself. Thank you. Robert McClenon (talk) 19:21, 29 January 2021 (UTC)[reply]

Do softwares cause screen flickering?

Lambiam RunningToMars Hohum I Uninstalled cracked IDM software in my laptop few days back. From then laptop runs smoothly without screen flickering. I thought screen flickering related to hardware problem.

Do softwares make screen flickering? Rizosome (talk) 15:59, 28 January 2021 (UTC)[reply]

While running, apps can make your screen do about anything. Since IDM runs in the background, it is theoretically possible. In particular, without mucking with the screen, it might interfere with the smooth display of streamed video if background downloads consume too much capacity of a strained Internet connection, leading to local congestion. Or it interposes itself between the receipt and the displaying of the media. Whether there is indeed a causal connection or the problem vanishing together with the uninstalling is merely a coincidence, is impossible to tell, but I saw a possibly related complaint here. --Lambiam 16:54, 28 January 2021 (UTC)[reply]

January 29

What devices really needed to solve P versus NP ?

I took interest in one of the open question: P versus NP problem. What devices really needed to solve it ? Rizosome (talk) 05:00, 29 January 2021 (UTC)[reply]

A quantum computer. Here is a nice easily understandable article: https://www.quantamagazine.org/finally-a-problem-that-only-quantum-computers-will-ever-be-able-to-solve-20180621/ 41.165.67.114 (talk) 07:24, 29 January 2021 (UTC)[reply]

P = NP is a purely mathematical statement, just like the Mertens conjecture, Fermat's Last Theorem and Goldbach's conjecture. The Mertens conjecture and Fermat's Last Theorem have lost their conjectural status: the former has been settled in the negative (the conjecture is false) and the latter has been solved in the positive (the conjecture is true, and it is indeed a theorem). The status of Goldbach's conjecture is still open; most mathematicians who have looked at, starting with Euler, think it is true, but the question may keep evading the combined ingenuity of all minds and remain unsettled forever. Precisely the same holds for the question whether the two complexity classes P and NP coincide or not. Most theorists think they differ, since no one has found a polynomial-time algorithm for any NP-complete problem, but that does not necessarily mean no such algorithm exists, and no one has found a proof that no such algorithm can exist. To settle the question requires a bright mathematical mind – whether human, an AI, or a hivemind – to come up with a mathematical proof of either the statement P = NP or the statement P ≠ NP. Neither more nor less is required. The devices needed are mathematicians. --Lambiam 09:07, 29 January 2021 (UTC)[reply]

What does "fillers" mean in video editing software?

From here , I want to know "fillers" mean in video editing context? Google didn't help me much. Rizosome (talk) 15:20, 29 January 2021 (UTC)[reply]

It's not a technical term. Sometimes the stabilization software will need to create a portion of the screen where there is no original video (because things have shifted during the stabilization process) and something needs to go there. "Filler" is a generic English term for anything that covers up or over gaps or holes in something, so that's the term that got used. It's the second sense listed here. Matt Deres (talk) 16:43, 29 January 2021 (UTC)[reply]

The filler, using technical terms, is a black matte. The original video is transformed to steady it and then superimposed on a black matte. 97.82.165.112 (talk) 15:57, 31 January 2021 (UTC)[reply]

Specifying a file for both StdIn and StdOut in Java using Windows cmd

I have written the following Java class called Test.java:

import java.util.Scanner;

public class Test {
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int value = in.nextInt();
		System.out.println(2 * value);
	}
}

I can run the compiled class file from the command line on Windows and have it use an arbitrary file for standard input by using:

java Test < file.txt

and I can do the same for standard output by using:

java Test > file.txt

How do I specify both an input file and an output file? --Puzzledvegetable^{Is it teatime already?} 15:53, 29 January 2021 (UTC)[reply]

Fairly certain that's just going to be this: java Test < input.txt > output.txt. Don't have ready access to a Windows machine, so I can't confirm. Jdphenix (talk) 19:09, 29 January 2021 (UTC)[reply]

SQL question - using MAX of a different field to find something else.

Let's say I have a dataset with customers, stores, products, sale dates, and prices. If I wanted to find the last sale date for an item I could do this:
select product, max(sales_date) from sales group by product
But what if I want to find the last sale price for each product from each store (and not include the sales date in the return)? It seems like I should be able to use a case statement including a MAX function, but that does not parse (as an aggregate; I thought maybe it would work as an analytic function, but it doesn't seem to be what I want. Basically what I want to be able to see is one product per one line and use CASE statements to split up the different stores into columns. Example:
PRODUCT NYC CHI TOR Carrots $15 $14 $18 Bananas $12 $10 $15
That doesn't seem crazy, but I can't seem to figure it out. Any help? Matt Deres (talk) 17:04, 29 January 2021 (UTC)[reply]

Assuming Oracle based on the link, but you're looking for PIVOT. If you don't know how many columns you'll have, you'll have to resort to dynamic SQL or having application code process the rows into columns. Jdphenix (talk) 20:37, 29 January 2021 (UTC)[reply]

Yes, sorry, it is Oracle, but my issue isn't with the pivoting (I use CASE statements to split that stuff up), it's with returning the price associated with the latest sell date. I might have a thousand sales on the carrots in Toronto; I want to find the last one and return the price on it. Matt Deres (talk) 20:49, 29 January 2021 (UTC)[reply]

This is postgresql, but everything here is as far as I know ANSI SQL,

insert into products values
('Bananas', '01-21-2021', 'CHI', 13),
('Bananas', '01-20-2021', 'CHI', 14),
('Bananas', '01-21-2021', 'TOR', 18),
('Bananas', '01-20-2021', 'TOR', 16),
('Carrots', '01-21-2021', 'CHI', 9),
('Carrots', '01-20-2021', 'CHI', 10),
('Carrots', '01-20-2021', 'TOR', 9);

with sale_dates_by_location as
(
select 
	product, 
    location, 
    max(sale_date) as sale_date
from products
group by product, location
)

select 
  products.product, 
  products.location, 
  products.price
from products
join sale_dates_by_location cte on 
  cte.sale_date = products.sale_date and
  cte.product = products.product and 
  cte.location = products.location

This result set will show price by product and location. Jdphenix (talk) 21:01, 29 January 2021 (UTC)[reply]

@Jdphenix Thank you very much - I'll give it a shot as soon as I can access that stuff again. Matt Deres (talk) 20:29, 1 February 2021 (UTC)[reply]

February 2

Delete a file in Git and add another file with the same name

At work I am using Git for source control. I found that one file had become useless so I used git rm to delete it and git commit to confirm the changes. Now I have later found out that I will probably need to add a different file under the exact same name. Is it OK if I simply use git add and git commit to add it, or will I somehow mess up the version history? JIP | Talk 02:02, 2 February 2021 (UTC)[reply]

It should work just fine. WhoAteMyButter (📨│📝) 05:01, 2 February 2021 (UTC)[reply]

Question about working from home

Because of the COVID-19 pandemic, I have been forced to work from home for almost a year. I quite like the situation because I can avoid spending time for the trips to get to the office and back. But there is a fundamental question here.

I have two separate computers. My personal computer, a HP Z420 workstation running Fedora 32 Linux, and my work computer, a Thinkpad laptop running Windows 10. Every single weekday I have to switch between the two, because I only have one monitor and one Internet connection. This has become a burden.

At my previous job I worked briefly from home, using my boss's computer in his office, connecting to it via TeamViewer, which runs both on Linux and on Windows. I'd like to take my work computer back to the office and connect to it via TeamViewer like I was doing in my previous job, but there's a problem. In my previous job, my boss initiated a TeamViewer session every day and invited me to join it. Now I would have to either travel to the office myself, which defeats the point of working from home, or ask someone at the office to initiate a TeamViewer session for me from my work computer.

Is there some way to have a TeamViewer session permanently open, or is there a different way to connect to a Windows 10 computer remotely from a Fedora 32 Linux computer? JIP | Talk 02:11, 2 February 2021 (UTC)[reply]

@JIP: It looks like it is possible if you enable Remote Desktop on your Windows system and use an RDP client on your Linux system. See [1]. It may depend on which version of Windows you are using. RudolfRed (talk) 03:14, 2 February 2021 (UTC)[reply]

JIP, while I have not used it personally, I have it on good authority that Synergy might be able to do what you want. Unless you are married to TeamViewer. Elizium23 (talk) 04:08, 2 February 2021 (UTC)[reply]

Is https://www.teamviewer.com/en/info/unattended-remote-access/ any help? I have used Teamviewer without setting up a call on the remote machine - although it does need to be left on permanently. Another option you might explore is a KVM switch and a router or Ethernet switch for your internet access.

Sorry, I can't help with your technical question, but could I ask what the burden is? I'm in broadly the same boat and saved myself some time by getting extra cables so that, for example, changing my monitor over doesn't require physical hot swapping, just switching of inputs via the settings buttons on the monitor. Time for work? Switch the input to HDMI. Time for fun? Switch to mDP. Maybe that's a simpler option? Matt Deres (talk) 19:53, 2 February 2021 (UTC)[reply]

How are you connecting to the Internet? If you have a broadband router, then they generally have several network sockets. Buy an extra cable and connect both machines to the router. If not, buy a simple router to act as a splitter. Or, can one of the machines use wi-fi?
As Matt says, most reasonably modern screens will accept multiple inputs and allow you to switch between them. So, get a second video cable and all should be well. All the remote access stuff seems rather vulnerable to me — GhostInTheMachine ^{talk to me} 21:02, 2 February 2021 (UTC)[reply]

Teamviewer allows you to set up a password for unattended access. This will work limited in the free version, but the commercial version does offer this. The alternative is mentioned above, Remote desktop access usually gives better performance but, for security reasons, should only be done from an internal network, so you should have a VPN connection to your work for this. This is not required for Teamviewer, where the only requirement is an internet connection. Rmvandijk (talk) 08:39, 3 February 2021 (UTC)[reply]

How would I use 4chan in China?

4chan is a popular imageboard website. The website is not blocked in China at the moment, but to submit a post, you need to complete the reCAPTCHA, which does not work in China. However, 4chan does not let you submit a post from a VPN. Is it possible to complete the CAPTCHA while connected to the VPN, disconnect the VPN, and quickly submit while the green check mark is displayed? Félix An (talk) 02:54, 2 February 2021 (UTC)[reply]

4chan does have a "pass" system, (see here). It does cost money, but VPNs cost money regardless. WhoAteMyButter (📨│📝) 02:57, 2 February 2021 (UTC)[reply]

I was trying to figure out a possible way to get it to work without paying extra. Oh well, if it I guess I might just not post there then while I'm off studying in China (lots of annoying stuff there anyways). I'm just figuring out how I would use many of my favourite websites while I am off to study in China for the next 4 years. Thanks! Félix An (talk) 03:03, 2 February 2021 (UTC)[reply]

February 3

Why do power percentage in Bluetooth devices always show in multiples of 10?

In my mobile and laptop, power percentage of my Bluetooth headphones always starts with 100%, 90%, 80%.....so on.

Why do power percentage in Bluetooth devices always show in multiples of 10? Rizosome (talk) 13:43, 3 February 2021 (UTC)[reply]

Likely because they don't need to be polled much. See the specification document here, (Battery Service, v1.0) under the heading "3.1 - BATTERY LEVEL".

For many devices, the battery level value will not change frequently; therefore it is recommended not to poll this characteristic value at a high frequency

Some devices do send 1% intervals, others 5%, 10%, or anything else. The specification says nothing about what levels they must poll at. WhoAteMyButter (📨│📝) 21:04, 3 February 2021 (UTC)[reply]

I don't know much about the specifics of Bluetooth, but I can provide an educated guess. A major chipset vendor likely only supports reporting battery status in 10% increments. Jdphenix (talk) 21:56, 3 February 2021 (UTC)[reply]

@@ Line 177: / Line 177: @@
 :Likely because they don't need to be polled much. [https://www.bluetooth.com/specifications/specs/battery-service-1-0/ See the specification document here], (Battery Service, v1.0) under the heading "3.1 - BATTERY LEVEL". {{Quote frame|For many devices, the battery level value will not change frequently; therefore it is recommended not to poll this characteristic value at a high frequency}}
 : Some devices '''do''' send 1% intervals, others 5%, 10%, or anything else. The specification says nothing about what levels they ''must'' poll at. [[User:WhoAteMyButter|<span style="color:#ffb300;text-shadow:1px 1px 6px rgba(255,153,0,0.6)">WhoAteMyButter</span>]] ([[User talk:WhoAteMyButter|<span title="Talk Page">📨</span>]]│[[Special:Contributions/WhoAteMyButter|<span title="Contribs">📝</span>]]) 21:04, 3 February 2021 (UTC)
+::I don't know much about the specifics of Bluetooth, but I can provide an educated guess. A major chipset vendor likely only supports reporting battery status in 10% increments. [[User:Jdphenix|Jdphenix]] ([[User talk:Jdphenix|talk]]) 21:56, 3 February 2021 (UTC)