Wikipedia:Reference desk/Archives/Computing/2011 November 7

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November 7

VLC seek bar

Hi,

I'm running VLC player 1.1.11 and it seems that they've introduced a "feature" whereby the time seek bar now only has access at fixed intervals. In other words it does not let me select a specified time, but jumps to a seemingly arbitrary step position when I click. Sorry for the poorly worded question. Has anyone had the same problem/know how to fix it? I'm running Windows 7 Pro

Cheers, --58.175.32.245 (talk) 05:28, 7 November 2011 (UTC)

Actually after testing with other videos I think it was the video that was at fault (it was a video tutorial and the software must have thought it somehow useful to prevent you from continuous time seek! --58.175.32.245 (talk) 08:33, 7 November 2011 (UTC)

Just guessing, but the video in question might have very few key frames (I-frames), and VLC may jump to the nearest key frame when seeking to avoid a long delay. -- BenRG (talk) 04:14, 8 November 2011 (UTC)

3d model evolution simulator program

I've seen videos of 3d models (for thermal heating I think) where the shape of the model (a reflector in this case) was determined by an evolution algorithm that, as far as I know, made a huge number of small changes to the shape and basically "evolved" the shape until its efficiency was at a maximum. The shapes it was coming up with were really interesting, and obviously not something you would come up with if you were to just try a bunch of different shapes and simulate them yourself.

I'm wondering if there is any of this kind of software that is freely available, or even user-friendly, though I imagine that there's not much need for such software outside of the manufacturing industry, so there's not much need for the public to have access to it. I would like to try some designs in aerodynamics and with fan blades. Thanks! 99.199.59.120 (talk) 06:46, 7 November 2011 (UTC)

YouTube viewer statistics

Anyone here interested in how Youtube's insight data representation works? I have been attempting to work out the total number of different people that have seen anything I have done on the site, however I have a question regarding what some of the statistics mean in practice. I looked into the total number of unique users data, which is given as a 30 day running total, would I be right in thinking then that where the total for the first 30 days is 1200, and for the subsequent 30 days is 2300, there is no way of knowing how many of those original 1200 are within the second group? Or does it discount people continuously from their first visit in spite of being a running total? I thought what this data meant was that the total number of interested people could be anywhere between 2300 and 3500, with no way of knowing more precisely.

But then, being me, I looked up the numbers of views at various intervals across the 30 days, divided one by the other to find the average number of views per person, and found that after rising quickly, it remains around the same level for the last couple of weeks, so I divided the total number by that, and what did I get..? 3500. So, does this answer my above question? Anyone here know more about how they calculate this?

148.197.81.179 (talk) 10:57, 7 November 2011 (UTC)

About Software development process

Hi,

I'm Ranjan.. I'm beginner to software(PHP) development job.. I had many doubts to creating web pages interactively.but i searched many of the websites still i remains poor. so i need wikipedia help. how to work efficiently and learning all about PHP(Hypertext Preprocessor)... Please give some tutorials to my mail,...

Thanks & Regards,

RANJAN — Preceding unsigned comment added by Ranjan111 (talk • contribs) 12:18, 7 November 2011 (UTC)

There are millions (if not billions) of things you can do with PHP. Without knowing what you plan to do, it is very difficult to point you to a relevant tutorial. -- kainaw™ 13:52, 7 November 2011 (UTC)

Mozilla firefox

I have problem with my mozilla fifrfox browser. It is that I have re-install it every time or else if I try through my shortcut, web pages do not open. How do I solve this/ Sumalsn (talk) 12:33, 7 November 2011 (UTC)

What operating system is your computer running? What exactly happens when you launch Firefox? What changes if you reinstall it? Comet Tuttle (talk) 21:17, 7 November 2011 (UTC)

Editable -> non-editable PDF

I have an editable PDF document that I edited recently with FoxIt (on Windows) and Document Reader (on Linux). I need to print said document at a local Kinkos, which has only Windows machines. However, I just learned that Adobe allows someone to fill in the fields, but not to actually save them. Thus, when I pull up the document in Adobe Reader for Windows, it clears the fields I've already typed in.

How can I save this document on another Windows machine so that I can port it back to Kinkos and print it out? 68.232.119.30 (talk) 16:24, 7 November 2011 (UTC)

If I "save as" a PDF form in Okular or "save a copy" in Evince (that's Document Viewer), both on Linux, the form-fillings get stored in the document. At least that's true for a simple PDF form I create myself (in Scribus); it seems some forms can have a "submit by email, don't allow printing" protection. -- Finlay McWalterჷTalk 17:32, 7 November 2011 (UTC)

Character representations in ASCII and hexadecimal

I'm fairly sure I grasp how characters are represented in ASCII: it's a seven- or eight-bit code, with each binary string corresponding to a character. However, it is also possible (common?) to index these characters using decimal numbers within human to human communication. Is that right? I also need to know how characters can be represented using hexadecimal, and the differences between character representation in ASCII and hex, but it's not in either of the textbooks I'm using. Can someone fill me in? Thanks in advance. —Anonymous Dissident^Talk 22:14, 7 November 2011 (UTC)

ASCII is strictly a 7-bit code. Because computers work in bytes (now) character data was (at least until unicode became common) usually (in the west) sent with a tacit understanding (or sometimes an explicit declaration) of the extended alphabet that the 8th bit was used to support (often a code page definition). It's rare to see the character code spelled out except in technical discussions (mostly by computer or communication engineers), but when it is there's not much consistency - you might see it simply written in hex (13) where the base is implicit, with a prefix or suffix that denotes hex (0x13 or 13h) or a hex char (\x13), as the control code (^M) or as a textual description of what it is (carriage return). It's very rare to see characters described in octal (partially because octal is pretty rare in general, but mostly because we're not using some weird architecture like a PDP-1 where the number of bits in a machine word is a multiple of 3). As to which of these many representations is appropriate, I'm afraid it depends on context. -- Finlay McWalterჷTalk 22:53, 7 November 2011 (UTC)

Stuff I forgot to say: it's also rare to write it in decimal and (unless you're talking about how bits are stored or transmitted physically) very rare indeed to consider then in binary. Incidentally, once you've got your head wrapped around this, take a look at UTF-8 which extends ASCII to support the gazillions of alphabets in the unicode domain in what I personally think is a wonderfully clever way. -- Finlay McWalterჷTalk 23:03, 7 November 2011 (UTC)

Alas; what has happened to the hex notation of my youth? $200, $2000, $3D0. Comet Tuttle (talk) 23:49, 7 November 2011 (UTC)

The ASCII code maps each character to a number. The base used to write those numbers can be whatever you feel like using. Looie496 (talk) 23:18, 7 November 2011 (UTC)

(EC)I think you just haven't firmly grasped the concept of hexadecimal, by your uncertainty about representing characters in ASCII and hex. Let's start off with something you're probably more familiar with. Whether you use the Arabic numerals 0, or spelled it out as "zero", they are the same number, just represented in a different way. When you have a capital "A" in ASCII, this is represented by decimal 65, which is equal in value to hexadecimal 41 (41 hex is adding 65 ones to 0 in base 16, or that the absolute value of 41 hex is the same as the absolute value of 65 decimal). In other words, there is no difference between character representation in ASCII and hex, other than the base used. Hope that helps. --Wirbelwindヴィルヴェルヴィント (talk) 23:53, 7 November 2011 (UTC)

Thanks for your prompt help, all of you. The general consensus seems to be that there is only a superficial difference between the representations (Looie496 made this particularly clear). This is what I had always assumed, until I saw this question: Q 25 (a). Would it be appropriate to say something along the lines of what Looie said, or is there more detail to add? —Anonymous Dissident^Talk 00:05, 8 November 2011 (UTC)

(My consternation is due to the fact that a 3 mark question generally requires as much as 100 words of discussion, and I don't see how there is that much comparing and contrasting to be done.) —Anonymous Dissident^Talk 00:08, 8 November 2011 (UTC)

At best it's a poorly worded question, and doesn't really compare like for like. It's perfectly reasonable to talk about an ASCII carriage return as 0x13; that's both hex and ascii. -- Finlay McWalterჷTalk 00:26, 8 November 2011 (UTC)

If you're thinking of the carriage return (^M), then it's D or 0D in hex, not 13. So it would be 0x0D, 0Dh or \x0D. 13 in hex would be 19 in decimal, meaning ^S. JIP | Talk 06:58, 8 November 2011 (UTC)

The carriage return is 13 decimal. Finlay sometimes makes errors! I am shocked.  Card Zero  (talk) 18:58, 9 November 2011 (UTC)

Yes, what on earth do they have in mind? Searching around a context, I think perhaps you should see the question in the light of question 23. There I see a story about doctors sending messages over a network, using a particular syntax definition which can include hexadecimal numbers and ASCII characters - for instance it says <space>:: = ASCII character 32. Presumably ASCII here just means "a character as typed" and hexadecimal means "the ASCII number of the character". (These are usually written in hex, as Finlay says.) So the most obvious thing to say - the only thing I can think of - is that in hex you can enter non-printing characters like space and carriage return, which if entered in raw form (apparently "ASCII" in the parlance of the question) would cause problems since they have syntactical meaning (separating items or entries).  Card Zero  (talk) 19:08, 9 November 2011 (UTC)

Excel question

Is there a way to specify in an Excel formula "everything in the column from *cell such-and-such* down"? Suppose that I want this "summing cell" to sum everything in column B starting at row 15. The formula "=sum(B:B)-sum(B1:B14)" only works if this summing cell is not in column B ... and what I'm trying to do is put a sum row up in row 10. I could do "=sum(B15:B999)" but that strikes me as inelegant. Comet Tuttle (talk) 23:54, 7 November 2011 (UTC)

I think in Excel, you're stuck with "=sum(B15:B999)". In Google spreadsheet, this was solved with "=sum(B15:B)". --Wirbelwindヴィルヴェルヴィント (talk) 00:15, 8 November 2011 (UTC)

I don't know if you'd call this "elegant", but you can use =SUM(INDIRECT("B15:B"&ROWS(B:B))). AndrewWTaylor (talk) 17:50, 8 November 2011 (UTC)

Hm, I'd call it educational rather than inelegant, personally. B999 it is! Thank you. Comet Tuttle (talk) 18:47, 8 November 2011 (UTC)

You could use a named range; that would look a bit more elegant, but really is just a different way to achieve the same thing. --jjron (talk) 10:20, 9 November 2011 (UTC)