FLV to Video ?? 
After a strictly and complext test, we found Ultra mp3 to FLV Converter is professional Flash Video Encoder and SWF Converter software which helps you convert FLV and SWF video files like MPEG to FLV, 3GP to FLV, WMV to FLV, mp3 to FLV, 3GP to SWF, MPEG to SWF, WMV to SWF, mp3 to SWF, etc. The mp3 to FLV Converter can convert so many video formats including DivX, XviD, mp3, WMV, MPG, MPEG, MP4, M4V, FLV, ASF, RM, RMVB, MOV, mp3, ASX, MKV, OGM, VCD files(.dat), VOB, mp3 to FLV and SWF formats.
Guide: How to convert mp3 to FLV with the mp3 to FLV Converter? Take Ultra mp3 to FLV Converter for example.Step 1: Download something to convert mp3 videos to FLV. 
Free download mp3 to FLV Converter (Note, like we have already explained, this mp3 to FLV converter is not only convert mp3 to FLV, this mp3 to FLV software can also convert many other video and audio formats to FLV formats).
Step 2: Launch the mp3 to FLV Converter:
Step 3: Click 
to input mp3 video file to be converted (batch convertsion supported, you can feel free to add as many as you wish). When "the add media files" popup window open you need to select "All Media Files" or "mp3P files(*.mp3, *.3G2)".
Tip: If your mobile phone video is *.mp4 formats, you should select MPEG-4 files.
Step 4: In the file list, click the FLV video file to be converted, the preview video screen may auto play the selected FLV file, just click pause button.
Step 5: Click the down arrow to choose FLV or SWF or both as you wish. 
Then click change, select the destination folder you want the converted mp3 to save.
Step 6: Click 
button.
the process shall be looked like this:
After successful converting mp3 to FLV, the converted video file shall be stored in the folder you have previously selected.
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Upload your FLV videos to YouTube like websites