Wikipedia:Reference desk/Archives/Computing/2011 March 24

= March 24 =

Projector light
I'm writing up some guidelines on making slides, but I wanted to check a factual matter here. On a typical LCD projector (where "pure white" is an absence of added color from the lamp, and "pure black" is the absence of light projected), does "pure red" (R:255, G:0, B:0) correspond to approximately 1/3rd the projected luminosity of pure white light? I know that the actual reflected luminosity depends on the screen surface, but I'm trying to come up with a basic generalization here. --Mr.98 (talk) 00:40, 24 March 2011 (UTC)
 * The response of human eyes to different wavelengths of light is variable (Eye provides some scant information), as is the reflectivity of the surface on which you project the image. On the other hand, the makers of LCD projectors and the associated drivers may have compensated for the eye's colour perception.  Sorry, I've not been able to fully answer your question.  Astronaut (talk) 03:41, 24 March 2011 (UTC)


 * If the projector is correctly calibrated (to sRGB) then the perceptual brightness will be around 0.299 R + 0.587 G + 0.114 B (these numbers are from the CCIR 601 standard; see YCbCr). -- BenRG (talk) 08:04, 24 March 2011 (UTC)


 * That is quite interesting. Does that mean, then, that pure green is some 2X the luminosity of red, and over 5X the luminosity of blue, or the other way around? --Mr.98 (talk) 12:07, 24 March 2011 (UTC)


 * Pure green is perceived as brighter then other colours. Take a look at Luminous efficacy and File:CIE 1931 Luminosity.png Nil Einne (talk) 12:25, 24 March 2011 (UTC)


 * In my experience, every projector has each color channel randomly mucked with on its way out of the factory, because LCD projector manufacturers loathe color, and want to convince everyone to do their presentations in black-and-white. From the people around me, I've picked up the practice of making the very first slide display all of the colors I use, so that I can diagnose any color-related problems ahead of time.  This is only useful if you have a way to globally change all uses of each color, of course.  If this isn't an option, I'd just be extremely conservative; don't count on two colors being distinguishable unless they differ by close to 255 in at least two channels.  I've seen pure red (255,0,0) be utterly illegible against black (0,0,0), but I bet it'd be readable against white (255,255,255).  (On the other hand, in light of what was said above, I'd be cautious about using pure green on a white background.)  Paul (Stansifer) 12:54, 24 March 2011 (UTC)


 * I agree, and this is essentially my point in bringing it up -- to discourage things like red text on a black background, which is unreadable. I've been trying to come up with a simple way of explaining it, and had thought about it in terms of luminosity, but maybe a better way to think about it is in terms of contrasts. Hmm. Again, this isn't for scientific consumption, just trying to give people a practical way of thinking about it. --Mr.98 (talk) 12:56, 24 March 2011 (UTC)

Help with Android Code
Hi, I'm going through some example code online. I'd like to preserve all of its functionality, except change it so it uses an arraylist to populate the list instead of a database.

https://github.com/findup/Android_Sample_TodoApp/blob/master/src/jp/co/example/testapp/MainActivity.java

Around line 127, it chooses to use a database connection to fetch content from the database.

Instead of fetching data from the database, I'd like to use an ArrayList to hold the data. Could anyone help me? Thanks! — Preceding unsigned comment added by Legolas52 (talk • contribs) 00:58, 24 March 2011 (UTC)

playstation 3 music mood
Life with Playstation requires music to be categorized by "mood". I have music on my PS3. How do I categorize it by mood? I can set a Genre, but even if I set it with one of the mood choices, it doesn't show up. I made a playlist for a mood, but that didn't work. I played some music, but it won't automatically get categorized. All I can find is that if I get the original CD out of my garage and re-rip it on the PS3, then it will categorize the mood. I don't want to do that. -- k a i n a w &trade; 02:04, 24 March 2011 (UTC)


 * Is this music that you've ripped on another machine (e.g. a PC) and then moved to the PS3? If so, it sounds like the PS3 ripper ap is setting the ID3 TMOO (mood) tag and your external ripper isn't. In the worst case, try (with a few sample mp3s) setting the ID3 TMOO with an ID3 editor on the PC, move them to PS3, and see if LwPS honours that "mood". -- Finlay McWalter ☻ Talk 13:05, 24 March 2011 (UTC)

Severe Virus/Malware Problem
I got one .exe file on mail and opened it. Result is disastrous.What shall I do. I had anti-maleware on my PC but this new virus has even made it ineffective. Please help  Jon Ascton    (talk)  03:34, 24 March 2011 (UTC)


 * If you recall the title of the e-mail, go onto another computer and look it up in Google, you might find advice there. StuRat (talk) 04:16, 24 March 2011 (UTC)


 * It really depends on exactly what damage the file has caused, hence the good advice from StuRat above. In the worst case, you will have to reformat your hard drive and reinstall everything, and restore your data files from backups.  In the best case, you can download a fix from a trusted site (using another computer), run this on your computer, and all will be well.    D b f i r s   13:03, 24 March 2011 (UTC)


 * Excuse me. It is dangerously irresponsible for you to claim to the querent that "all will be well".  There is plenty of malware that damages files such that a malware cleaner cannot repair them, and the querent will have to restore from a backup for the files to be usable again.  Any particular malware cleaner is also not 100% guaranteed to remove all computer viruses or other malware from any particular system.  That said, Dbfirs is correct that you should download antimalware software, such as the offering from Malwarebytes, using a different computer, then bring it over to your infected PC with a flash drive or by burning it to a disc.  See Reference desk/Computing/Viruses for more details.  Comet Tuttle (talk) 17:21, 24 March 2011 (UTC)


 * I don't Dbfirs is intended to say if a fix exists it's a guarantee all will be well. After all their first comment was 'It really depends on exactly what damage the file has caused'. Instead they were simply pointing out that there are two extremes where there is no hope for recovery, and where recovery is simple (and of course a lot in between). Nil Einne (talk) 20:00, 24 March 2011 (UTC)


 * Yes, sorry if I didn't make my comment clear. I was emphasising the two extremes, but the fact that the exe file disabled the anti-malware suggests that this might be a worst-case scenario.  StuRat's advice was good, as is Comet Tuttle's, and the link (above and below) gives much more detail.    D b f i r s   22:07, 24 March 2011 (UTC)

We have a whole subpage for this topic at Reference desk/Computing/Viruses. ---— Gadget850 (Ed)  talk 17:47, 24 March 2011 (UTC)

Firefox 4 and the disappearing bottom toolbar
I had been using a vital add-on called Gmail Manager for Firefox, but upon updating to Firefox 4.0, the location of the feature - the bottom right corner of the lower toolbar - seems to have been done away with. The add-on says it is compatible with FF4, so how does it work?

I tried asking at the mozilla help stations but they were no use. Appreciate any assistance! Thanks —Preceding unsigned comment added by 83.70.253.21 (talk) 14:04, 24 March 2011 (UTC)


 * I think they call that the "addon bar". Try checking firefox->options->addonbar. -- Finlay McWalter ☻ Talk 14:17, 24 March 2011 (UTC)
 * Comfirm, it's the addon bar. Nanonic (talk) 14:19, 24 March 2011 (UTC)


 * Thanks guys! —Preceding unsigned comment added by 83.70.253.21 (talk) 14:32, 24 March 2011 (UTC)

This addon attempts to restore the functionality of the status bar 82.43.90.38 (talk) 15:11, 24 March 2011 (UTC)

Video Editing Software with Timeline View of Audio
I'm looking for preferably free software that I can edit video with and see the audio timeline a la Audacity. I currently use both Windows 7 and Linux platforms. I'd prefer to do this on Windows, but Linux is ok too. I just want to be able to edit my video while being able to see the audio levels along with the timeline. The audio need not be multichannel (stereo or higher), it can be mono. Also, I'm editing mpg-2 mostly, but i can do it in just about any format. Windows Live Movie Maker doesn't have an audio timeline as far as I can tell (although the XP version did). Any recommendations? Thank you very much. -Rajah (talk) 18:00, 24 March 2011 (UTC)


 * For notes on video editing software in general, see the thread from a couple of weeks ago at Reference desk/Archives/Computing/2011 March 18 I use Adobe Premiere for video editing and it does show the video along with the audio timeline ... but it's not free.  Comet Tuttle (talk) 18:26, 24 March 2011 (UTC)
 * Thanks, I found Windows Movie Maker 2.6 and that works. --Rajah (talk) 21:51, 24 March 2011 (UTC)

Forcing registry re-read in Windows 7
I have a special mouse driver from my mouse manufacturer. It works fine, and I need it, except that it resets some mouse settings on each login/boot. I know how to change these in the registry. For a simple workaround I am trying to just rewrite that portion of the registry on each boot, which should fix it. However, I don't know how to force Windows 7 to reload the new settings without going into control panel and doing it manually. How can I essentially HUP windows so it reloads my new settings? Is it possible alternatively for me to directly change these settings in a scriptable way? Peasandsoup (talk) 18:47, 24 March 2011 (UTC)


 * You can create a regedit script (FOO.REG) and run that in autoexec.bat (which should happen after the driver has done its mischief). This page has some info about how to do that. -- Finlay McWalter ☻ Talk 19:10, 24 March 2011 (UTC)


 * That's the method I am using, however changing the registry doesn't appear to update the mouse settings themselves unless you somehow force windows to re-read those settings. It's this that I'm having issues with. I also need the script to be run after the mouse driver/program makes its changes, which might require putting it in the startup folder rather than in the autoexec.bat Peasandsoup (talk) 19:20, 24 March 2011 (UTC)


 * I'm off out in a minute (so I can't test this) but it's my understanding that what Windows programs and drivers should do is to register for registry-change events and respond accordingly (which often means immediately). That's a paradigm closer to inotify than the reread-on-sighup you're thinking of. If my memory serves, the Microsoft bog-standard mouse driver does this, and responds immediately when you change its registry entries (for stuff like pointer-trails etc.)  So if the mouse driver in your case isn't, that would suggest it's not registered for the events (presumably because its authors don't anticipate, or aren't interested in, changes done by others). In that case I don't know of a way to force it. -- Finlay McWalter ☻ Talk 19:37, 24 March 2011 (UTC)
 * Thank you for the help, but the registry changes aren't immediately reflected in the mouse behavior. In fact, changes to the registry aren't reflected when the right panel's opened up in Control Panel either. Maybe what I need to do is write a program that does the appropriate calls to change the value. I don't have any experience programming for Windows though. Does someone know what calls I need to use to change ControlPanel registry values? The specific key by the way is HKCU\Control Panel\Desktop (Although \Mouse works the same way). Peasandsoup (talk) 20:40, 24 March 2011 (UTC)


 * This can't be a driver—the values in HKCU\Control Panel\Desktop have no meaning to drivers. It must be some user-mode application. The solution to your problem depends on what application it is and how it runs. What is the name of it? Why would it reset registry settings in the first place? Is it a "feature"? What is supposed to be the benefit? Are you 100% sure that this behavior can't be turned off? Are you sure that this software is to blame at all?


 * Windows supports logon and logoff scripts (which can be .bat files) that run just after login or just before logout (before/after everything else). You can add logon/logoff scripts with the group policy editor (Win+R, "gpedit.msc"), in User Configuration → Windows Settings → Scripts. But, again, whether this will work depends on what sort of program you're fighting against.


 * You could also make the offending registry key read-only by editing the access control list. Unfortunately, this is nightmarishly complicated, but bear with me. Select the Desktop key in Registry Editor, go to Edit → Permissions, click "Advanced", uncheck "Include inheritable permissions...", choose "Add" in the dialog box that pops up, and for every line that says "Full Control" in the "Permission" column, select it, click "Edit...", and uncheck the Allow" box of the "Set value" row. Then okay your way out of the dialog boxes. If you ever want to write-enable the key again, repeat everything up through clicking "Advanced", then select all the permissions lines and click "Remove", then re-check "Include inheritable permissions...", then okay your way out. -- BenRG (talk) 02:46, 25 March 2011 (UTC)