I want to convert music mp3 to swf. Which is the best software that gives the good sound quality with smaller file size? Please suggest
SWF is a ShockWave Flash file, and it can embed MP3's in it - it doesn't convert between formats. I think you are either misinformed, or thinking about another format. For future reference, what operating system are you running? I know great audio conversion tools on Linux, and on Mac, but I haven't used windows for production since 2001, although I imagine there are some decent audio tools for that as well. Check Audacity.sf.net < it's a great free wave editor that can save t a variety of formats - give it a download and try it out, you've got nothing to lose cause it's free and open source!
Audacity is great for amateurs, does things that I just don't understand. You won't get anything much smaller than mp3 but you can reduce the sampling rate if your ears can stand it. (Use Audacity - but you need to add a lame3.dll plug-in).
.ogg is smaller filesize than MP3 at the same quality settings. There are plenty smaller and more efficient than MP3, but you have to remember what the end purpose will be and see if you can get a player that will support the format.