I download videos in mp4 or flv format but I need to convert them to mpeg 1/2/3 so that I can watch them on my special gadget.
I think I need a program.
any suggestion thanks
Use ffmpeg utility, it's awesome.
1. Install:
sudo apt-get install ffmpeg
2. Convert:
ffmpeg -i input.mp4 output.mpeg
PS: For available formats supported by ffmpeg:
ffmpeg -formats
this can be done with avconv
sudo apt-get install libav-tools
and then use (for mpeg 2)
avconv -i video.mp4 -c:v mpeg2video video.mpg
also, check the (impressive) list of audio and video codecs with avconv -codecs
There are many good video Converters wich can run CLI or GUI.
I advise you to give a try to transmageddon.
To install just:
sudo apt-get install transmageddon

In the output field you can specify MPEG4.
Another pretty easy to use is Handbrake

To install in ubuntu:
sudo apt-add-repository ppa:stebbins/handbrake-releases
sudo apt-get update
sudo apt-get install handbrake
Use avconv this way:
avconv -i file.mp4 -c:v mpeg2video -q:v 2 -c:a libmp3lame output.mpg
I use Arista Video Transcoder on Ubuntu. Though not highly rated, it is very good for video conversion. I use it to convert videos to match PSP's supported framerate and it does the job just fine. Most of the other prominent ones strip the quality while converting to a lower resolution, but Arista maintains the quality even when stepping the resolution down to that of a mobile device's.