I would've tried MKVMerge or MakeMKV but they won't work on MP4 files. Does anyone have a way to just add the track? Cause adding it via Handbrake or something would take too much time.  Thanks.
I've got an MP4 video file and I want to add another AAC audio track to it. I've tried YAMB and MeGUI (frontends for MP4Box) and it plays correctly in Zoom Player, but it picks the wrong track in WMP and plays both at once in Quicktime. I think this might have to do with designating the default audio track somehow.  Does anyone know how to specify the default audio track with YAMB/MeGUI or know of another way of adding a track to an MP4 file?
80's Animated movie: An old man joins mission to save a boy stranded on a hostile world Formal basis for variable substitution in limits So we do a lot of variable substitution in limits at school. Stuff like $\lim\limits_{x\to5}\ (x+1)^2\ =\ \lim\limits_{y\to6}\ y^2$, where we define the substitution $y = x + 1$.  But I've never been clear on what exactly the theoretical basis for this is. What is the formula that you're actually applying when you do variable substitution? What are the formal conditions under which it is possible?  My conjecture would be the following:  For all continuous $f$, and all real $a$: $\lim\limits_{x\to a}\ (f\circ g)(x)\ =\lim\limits_{x\to g(a)}\ f(x)$, where $g$ is a continuous function  So to take my first example, $f$ would be $x^2$, $g$ would be $x + 1$, and $a$ would be $5$.  Am I in the right area? If this is correct, can it be proven using $\epsilon$-$\delta$? I had a half-hearted shot at it the other night and didn't get anywhere. When A and B are positively related variables, can they have opposite effect on their outcome variable C? A is positively related to B.  C is the outcome of A and B, but the effect of A on C is negative and the effect of B on C is positive.  Can this happen? Elliptical orbits of planets As we know, the velocity of the planet changes as it orbits around the sun, both in its magnitude and direction. The centripetal acceleration causes the change in the direction of velocity but I want to know what is the tangential force that acts on the planet to change the velocity by its $magnitude$. The answer normally as to why the speed changes is: If  the  force  that  the  Sun  exerts  on  the  planet increases  (as  the  planet moves closer),  then  the acceleration   of  the  planet must  increase,  resulting  in a  higher  orbital  speed,  and vice  versa. But this force is not along the body but towards the sun. So such a force should only change its direction. Render not showing UV texture I have added a texture to a cube in the UV editor and it shows up fine in textured view  But when I render it there is no texture  What have I done wrong? Need to get logfile smaller Is there an algorithm for N body simulations in General Relativity I am new to general relativity but have a background in computer science.  Why is it so hard to do n-body simulations in GR?  For example, there could be a program which takes the properties (mass, position, velocity, etc.) of each particle as input and numerically integrates the evolution of the system using discrete but very small time steps.  If we throw enough memory and computing power at it, we can get arbitrarily close to the 'real' solution.  I assume the entire histories of the worldlines would need to be known, in order to calculate things like gravitational waves.  I have downloaded programs which show the evolution of the Schrodinger equation, so I am surprised they are so hard to find for GR.  Some responses I've heard elsewhere are 'the equations are nonlinear,' but from what I hear numerical algorithms are great for these types of problems.  What types of numerical algorithms are out there for GR? I am a US citizen and have recently visted the UK  with simply a passport which allowed me to vist for 6months I have heard rumors that I am obligated to stay in the US for a Equal amount of time that I have visited the UK before I am able to return, but I am struggling tour no any proof of this obligation .. Am I missing somthing or is it simply not true In Visual Studio, we've all had "baadf00d", have seen seen "CC" and "CD" when inspecting variables in the debugger in C++ during run-time.  From what I understand, "CC" is in DEBUG mode only to indicate when a memory has been new() or alloc() and unitilialized.  While "CD" represents delete'd or free'd memory.  I've only seen "baadf00d" in RELEASE build (but I may be wrong).  Once in a while, we get into a situation of tacking memory leaks, buffer overflows, etc and these kind of information comes in handy.  Would somebody be kind enough to point out when and in what modes the memory are set to recognizable byte patterns for debugging purpose? How can I merge properties of two JavaScript objects dynamically? Windows 7 sleeping during operations I've got Windows 7 set up on my media box.  It's set to sleep after 30 mins of inactivity, but it doesn't seem to work as advertised. In the last two weeks it's gone to sleep during a file copy operation and again while encoding an MP4 file.  Is there any way to get Windows to realise that it's actually busy? Why and how is the speed of light in vacuum constant, i.e., independent of reference frame? How to create a Wi-Fi Hotspot (in Access Point mode)? How to setup an Access Point (AP) mode Wi-Fi Hotspot?  Point to be noted: Wireless access points aren't the same as ad hoc networks. They differ significantly. In short, ad hoc networks aren't supported on newer devices and most Android, Windows Phone and Blackberry devices (and maybe iOS devices too), whereas AP mode Wi-Fi hotspots are. To get an idea about AP mode hotspots, ad hoc networks and their difference, refer to . How can I download a distribution? Am I right in thinking that the Drupal distributions that I can download from  are a standard Drupal core download with a load of other stuff added at /profiles?  Anyone know if there are any plans to create a dev branch of distributions that would automatically update the core version that the distribution is running on? Currently it seems that the distribution runs on whatever core version its developer has chosen.  And how can I use distributions with Drush? Is there an equivalent to drush dl drupal that will download a specific distribution?  And, finally, is there any difference between an install profile and a distribution? Enumerate alignment problem in theorem environment I'm using amsart. When I create an enumeration inside a theorem environment, the numbering is not aligned properly:  Theorem 14. (1) (2) (3) (4)   How do I shift the (2),(3),... to be aligned with (1)?  MWE:  \documentclass{amsart} \newtheorem{thm}{Theorem}[section]  \begin{document} \begin{thm} \begin{enumerate} \item Item 1 \item Item 2 \item Item 3 \end{enumerate} \end{thm} \end{document} What's the difference between executing a script like this:  ./test.sh  and executing a script like this:  . test.sh?  I tried a simple, two-line script to see if I could find if there was a difference:  #!/bin/bash ls   But both . test.sh and ./test.sh returned the same information. Prettify OS X console by coloring output? OS X terminal is not using colors for highlighting output from different commands, for example ls.   When compared with other systems like Ubuntu, this is a big loss of accessibility/productivity.  What solutions do I have to improve this experience? For the moment I found only this guide for  but I am looking for a more complete solution. How do I stop the excel file being in use? I'm opening an Excel file and I'm getting the File in use pop-up that says it's locked for editing by me. However, I've not got it open on this computer (I think I had it open and my machine blue-screened). How do I go about fixing this?  Should specify, this is a file on a file share.  edit I'm not talking about if this is being used by another user on another machine, this is only accessible by me on this file share. Maintaining Units of measure across type converstions What are the uses of "using" in C#?