sudo apt-get install ffmpeg
convert .flv to .mpg using ffmpeg
First you need to download your .flv file to a folder and you need to Open a terminal window and go in to the .flv file folder and type the following command
ffmpeg -i jokes.flv -ab 56 -ar 22050 -b 500 -s 320×240 jokes.mpg
Currently untested, but possible way to convert to MPG4. It properly converted the flv to an mp4 but when I tried to burn the mp4 to DVD using Nero the audio was lost. Properly need to properly convert the audio.
According to google search, the AC3 filter must be installed, that did not do the trick Ubuntu must have used some other codec to encode the audio where VLC had the built-in codecs.
http://ac3filter.net/project/1/releases (ac3filter_1_51a.exe)
ffmpeg -i inputfile.flv -acodec copy -vcodec mpeg4 outputfile.mp4
jokes.flv is the file you want to convert, so the name must be the same as the source file.You can name jokes.mpg whatever you want as long as it has the .mpg extension.
-b bitrate: set the video bitrate in kbit/s (default = 200 kb/s)
-ab bitrate: set the audio bitrate in kbit/s (default = 64)
-ar sample rate: set the audio samplerate in Hz (default = 44100 Hz)
-s size: set frame size. The format is WxH (default 160×128 )
Update:
I was able to convert an FLV file directly to DVD using the application DeVeDe. It's a bit basic but it was able to create a DVD with a menu system too. The audio ended up being on Track 3 for the test. It looks like audio moves around a little and I don't know how to specifiy where to put it. The program writes its output to an ISO which you can then test.