Convert any video into audio on Ubuntu

There are two methods by which you should convert any video in audio on Ubuntu 14.04.

  1. Through command line
  2. By using GUI

Through command line:

First you should install avconv. Just type two command in a terminal for installation.

$ sudo apt-get update
$ sudo apt-get install libav-tools

Writing the given below command for converting video into audio.

$ avconv -i amrit.mp4 -f mp3 amrit.mp3

Some points about the above command:

  • Don’t forget to replace the input file name with your video file name.
  • -i amrit.mp4 is the file that we want to convert (-i = -input).
  • -f mp3 is the format we want our output file to use it, you can switch to “wav” or “webm” if you want.
  • amrit.mp3 is the name of the output file.

By using GUI:

  1. First step you should install winff. For installing winff open a terminal and type the following commands:
    $ sudo apt-get install winff libavcodec-extra
  2. Second step is to open winff. Write a single command to open winff.
    $ winff

    By writing a above command Winff window is open like this


  3. Then in Winff window, do these
    • Add file
    • Select what catagory to convert (select Audio)
    • Select Audio file format (mp3)
    • Type the output folder for converted file

    For example :


  4. Then click the Convert button.

Therefore symbol in LaTeX

There is no therefore symbol in the default LaTeX packages. There are (at least) two ways of getting the symbol:

The package amssymb contains the therefore symbol definition. To use, do something like:


Alternatively, you can create your own therefore definition:


The amssymb therefore has tiny dots, whereas the definition above has large dots

Writing Subscripts and Superscripts in LaTeX

To get an expression exp to appear as a subscript, you just type _{exp}. To get exp to appear as a superscript, you type ^{exp}. LaTeX handles super-scripted superscripts and all of that stuff in the natural way. It even does the right thing when something has both a subscript and a superscript. You must provide formula or equation environment to our expression and this is provide by using $ exp $. For example

i) Writing subscript :

$ x_0 $
$ l_{eq} $
$ v_{(x,y)} $

ii) Writing superscript :

$ x^0 $
$ l^{eq} $
$ v_{(x,y)} $

iii) Writing both subscript and superscript :

$ x_0^0 $
$ l_{eq}^{eq} $
$ v_{(x,y)}^{(x,y)} $

Here _ is for subscript, ^ is for superscript and {} is used to treat every thing it it as a single unit.