Using a Mplayer option to keep the pitch at higher speeds of video or audio.

If you like to listen to an audio or watch a video at higher speed, the sound could get distorted, i.e. with the wrong pitch ("chipmunk mode"). In mplayer when you change the speed using the keys "[" to decrease or "]" to increase; the tempo is not adjusted accordingly. In command line a solution is with the use of  "-af scaletempo" option, example: 

mplayer -af scaletempo videofile.mp4

The speed can be included as 

mplayer -af scaletempo -speed 2 videofile.mp4

or being changed later with  the keys "[" or "]". 

In the case of using a "Mplayer" GUI, like in the case of "SMPlayer", the "-af scaletempo" functionality is already integrated. 

How to play movies with subtitles in mplayer

The basic command is:
$ mplayer name_of_movie.avi -vobsub name_of_subtitle 

As you can note, the name of the subtitle is written without any extension which usually are '.idx', '.ifo' or '.sub'.
The next command will do exactly the same than the first:
$ mplayer name_of_movie.avi -vobsub name_of_subtitle -vobsubid 0

If there is a second language available in the captions then you do:
$ mplayer name_of_movie.avi -vobsub name_of_subtitle -vobsubid 1

The name of the subtitles has to be exactly the same than the name of the movie.

Scaling the video in MPlayer

Example:
mplayer -vf scale=720:576 laverdad18092007.wmv