To convert mpeg4 to avi, you can use this video converter to do it.Very simple but useful.

http://www.leawo.org/video-converter/

Go to you homepage,  and find the post that you want to remove, on the top right corner you can click the button and find the delete option and  then click it to remove it.

If you means playing dvd movies on iPad by converting the dvd formats to iPad compatible video, you just need a dvd converter. Take the below one for a try.

http://www.leawo.org/video-converter-ultimate/

In fact, I like to eat almost everything except for the pork.

Using a Add-on for firefox or Chrome, or go to some website or download one program like this one(http://www.leawo.org/video-converter-ultimate/) to do that easily.

 The version is v2.1 with A2DP, EDR.

Source:http://www.gsmarena.com/motorola_atrix_4g-3708.php

It seems you can convert mkv to mp4 to save on your USB disk and then plug in the DVD player to play the movies.

The video converter I suggest you is this one, a simple-to-use and friendly one.

http://www.leawo.org/video-converter/

You can try Freemake , it is totally free.

You can easily do that by directly convert the facebook video to mp3 with this video converter ultimate(http://www.leawo.org/video-converter-ultimate/). 

Guide:

1.Open the program.Click the download button and then you will go to a download interface.

2.Input the video page, and then it will automatically remind you if download, choose the save as and select the mp3 as the output format.

3.Then the video will convert to mp3 quickly.

To convert video to auido,the easiest way is to use a video converter. And the steps are very simple. Just choose the output format in audio format like MP3 and you can get the audio. 

Video converter recommendation:Freemake or Leawo Video converter(http://www.leawo.org/video-converter/)