How to convert FLV to MP4:
Here I want to recommend a totally free software called Freez iPod Video Converter. It can convert FLV to MP4 video format. The output MP4 files can be divided into 2 types. One is MP4 encoded by MPEG-4 and the other one is MP4 encoded by H.264. Of course aspect from FLV, you can import AVI, MPEG, WMV, ASF, MOV, RM, RMVB, DivX, Flv, SWF, VOB, 3GP to MP4 compatible with your favorite iPod.
The simple guide for Freez iPod Video Converter:
Input FLV

2. Do the output settings

3. Specify the output folder and start conversion.

The interface is really easy-to-use. Just within three steps, the conversion will be done.
FLV Editor Pro is really professional editing software. It can edit FLV greatly and output various video formats like AVI, MPEG, MP4, MP3, 3GP, WMV, MOV and FLV. Moreover, it Provide two free functions. One is to trim FLV and the other one is to merge FLV. You can install the trial version to use these two functions freely. Of course, with the free functions, you can only output FLV without recoding.
The simple guide for FLV Editor Pro:
- Input FLV files:

- Trim and crop video:

- Add watermark:

- Combine FLV:

- Output FLV:

Windows Movie Maker:
Windows Movie Maker is the popular and free editing software which will be installed on your PC as the bonus as long as you have install Window Operating System. Generally it can be found at C:\Program Files\Windows Movie Maker. It owns attracting features: insert the transitions, add the title and credit, replace the music and cut any part you do not want, etc. However, the program doesn't allow input FLV directly. You have to use FLV to Video Converter to convert FLV to AVI. Moreover, you can only get WMV files ending with *.wmv.
Simple guide for Windows Movie Maker:
1. Import AVI videos.

2. Drag video files to storyboard for editing

3. Add transitions for video files.

4. Add titles or credits.
In the picture below, click “Make titles or credits” you will see the next screenshot:

Select one option to add title or credit.

5. Add pictures.

- Replace the music on timeline.

7. Output WMV files.

The simple guide for Aimersoft Video Converter for Mac:

Here are two free FLV players for mac. Use them to play FLV on your Mac OS and enjoy your favorite video or movies. Just download here: FLV Viewer for Mac and SWF & FLV Player (formerly SWF Movie Player).