I have a 9.5 GB MKV file, and I want to convert it a mpg or avi file using AVConv.  How can I accomplish this?
I tried to install ffmpeg in trusty/Ubuntu 14.04 and got the following message:  $sudo apt-get install ffmpeg  Reading package lists... Done Building dependency tree        Reading state information... Done Package ffmpeg is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'ffmpeg' has no installation candidate   Why isn't the package available?
As I have heard people did not trust Euler when he first discovered the formula (solution of the ) $$\zeta(2)=\sum_{k=1}^\infty \frac{1}{k^2}=\frac{\pi^2}{6}.$$ However, Euler was Euler and he gave other proofs.   I believe many of you know some nice proofs of this, can you please share it with us? What does the "static" modifier after "import" mean? I have installed Ubuntu on my laptop and now I want to remove it and the Grub Loader. How I can do it without the Windows installation disk (I cannot use the Recovery Console). How to run scripts without typing the full path? Understanding psql prompts "Above"/"below" before/after a noun Hyperref "enquotes" metadata No icons for automounted volumes on GNOME / Nautilius desktop on Ubuntu 19.04 Up to Ubuntu 18.04, using default GNOME/Nautilius desktop, when I inserted a (data file) USB stick it would automount and put a USB icon onto the desktop.  I find this very useful, especially for quick eject via context menu.  Now at 19.04, on USB insertion I do see a "banner" appear for a few seconds, but I no longer get any desktop icon .  I run under VirtualBox on Windows, but that has not changed and I do not think is at issue.  Ubuntu does still automount the stick at /media/&lt;username&gt;.  I found .  I checked in dconf-editor and both keys, including org.gnome.desktop.media-handling.automount-open, are set. The three lengths \textwidth, \linewidth and \hsize seem to all hold the width of the current line. At least I never saw some real difference between \textwidth and \linewidth in my code. Both seem to be identical even when changed, e.g. by a minipage environment.  Could someone give me an elaborate explanation of the differences between these lengths? I like to understand them in detail. I know that the first two are from LaTeX and the latter one from plainTeX.  There is also \columnwidth which seems to be identical to \linewidth or \textwidth in one-column mode, right? Except when the line is reduced by a minipage or quote etc. environment. What is the path of an MTP device in Windows? I am running Windows XP and have a phone mounted through USB by MTP.  In Explorer, its address is:  My Computer\SAMSUNG-SGH-I547\Phone\DCIM   I would like to execute a command line command such as  explorer "My Computer\SAMSUNG-SGH-I547\Phone\DCIM\Camera"   so as to quickly go to the Camera folder. (Right-clicking the device or anything in it does NOT provide a "Create Shortcut" dialog.)  But "My Computer" is not a valid PATH in Windows. Unlike USB flash drives, it seems the phone mounted by MTP does not get a letter drive name.  So, what is the path of an MTP device in Windows?  If the answer is there is no command line path, is there workaround? Second-order non-linear ODE $2tx'-x=lnx'$  I differentiated both sides with respect to x:  $x'+2tx''=\frac {x''}{x'}$  Substituting $p=x'$,  $p+2tp'=\frac{p'}{p}$  But I have no clue what can I do from here on.  EDIT: $t$ is the non-dependent variable. Prove that $|f''(\xi)|\geqslant\frac{4|f(a)-f(b)|}{(b-a)^2}$ Evaluate $\lim\limits_{n\to\infty}\frac{\sum_{k=1}^n k^m}{n^{m+1}}$ "Abusing" bounties for unlimited profit Six days ago I put a +50 bounty on  which wasn't asked by me, but to which I'd previously posted a pretty decent answer. Since then I've earned 130 reputation from upvotes on my answer, netting me +80 reputation and a bronze badge from no work.  It seems possible to slowly generate free reputation by "investing" in your answers like this. I expect I could repeat this perpetually and continue to profit from it.  This strikes me as an abuse of the bounty system. Should anything be done to prevent it?  EDIT: For more concrete questions:   If I put another bounty on this question after this one expired, would that be considered abuse? What if I did it several times? ( the answer was  "yes", but the author was doing so to promote his own project.) What if I didn't do it to the same question, but was constantly promoting questions I'd answered, in order to promote my answers? Kernel did not upgrade between 14.04 LTS to 16.04 LTS Disable sleep on laptop lid close in tty1 I'm using Ubuntu Desktop 15.10 on a laptop and it runs an Apache server with SSH as well. When using a GUI, I have the power options set to not sleep at all even when the laptop lid is closed, but recently I stopped the X-System and am now using TTY1 instead to save resources. However, in TTY1, if I close the laptop lid, the computer goes to sleep and prevents the SSH and Apache server from working. Any way to prevent this easily? The realistic answer I bet is to use Ubuntu Server instead (unless I'm mistaken and Ubuntu Server will also sleep on lid close) but I don't exactly want to switch yet unless there's an easy way to switch to it like you can switch from ubuntu-desktop to lubuntu-desktop? Any advice is welcome to prevent the computer from sleeping How can faces be rotated around their individual normals? In edit mode with these settings:   Face selection Pivot point: individual origins Transformation orientation: Normal   The faces don't rotate around the normals, is there another required setting that I overlooked? let q be an odd prime and p a prime dividing $1+n+\dots+n^{q-1}$. Prove that $p = 1 \mod q$ or $p = q$.  I don't actually know how to start, i thought of using fermat's little theorem or an application of eulers formula, but it didn't really give me any insights.   Any hints? While we know that every finite set is compact, how to prove that every infinite subset of $\mathbf{R}$, the set of all real numbers, is also compact in the finite-complement topology (also called the co-finite topology)?   What is the situation in the case of an arbitrary infinite set $X$ with the finite-complement topology? Can I use a 23 W CFL in a fixture that's rated for a 60 W incandescent? I have a lamp that is rated at 60 Watts for an incandescent bulb with a disclaimer to use a 13 Watt bulb instead when using a CFL replacement. Do I really need to respect that disclaimer? Would not a 23 Watt CFL be just as safe to use? It still draws less power than a 60 Watt incandescent, right?