How to convert variable frame rate videos? I have some old 3GP (mp4v codec)videos from my HTC desire S and when I try to drop them into Vegas they won't open so I decided to convert them to a format that would open. However when I convert to a standard mp4 template h.254 at a frame rate of 30, the video converts and plays back at twice the speed but the audio is original. 

I cannot figure out the frame rate for the original video according to Gspot it is 16.393 and other videos its 9.901 etc

Here is the information from the container 
3gp4: 3GPP Media (.3GP) Release 4  


mp41: MP4 v1 [ISO 14496-1:ch13]  
3gp6: 3GPP Media (.3GP) Release 6 Basic Profile  
Recommended Display Size: 800 x 480


How would I convert such videos to play back normally?

**EDIT INFORMATION FROM MEDIA INFO**  
Format                                   : MPEG-4  
Format profile                           : 3GPP Media Release 4  
Codec ID                                 : 3gp4  
File size                                : 208 MiB  
Duration                                 : 3mn 55s  
Overall bit rate                         : 7 430 Kbps  
Law rating                               : (empty)  
Released date                            : 0  
Encoded date                             : UTC 2012-04-29 18:18:23  
Tagged date                              : UTC 2012-04-29 18:18:23  
Classification                           : (empty)  

**Video**
ID                                       : 1  
Format                                   : MPEG-4 Visual  
Format profile                           : Simple@L6  
Format settings, BVOP                    : Yes  
Format settings, QPel                    : No
Format settings, GMC                     : No warppoints  
Format settings, Matrix                  : Default (H.263)  
Codec ID                                 : 20  
Duration                                 : 3mn 55s  
Bit rate mode                            : Constant  
Bit rate                                 : 7 416 Kbps  
Nominal bit rate                         : 8 000 Kbps  
Width                                    : 1 280 pixels  
Height                                   : 720 pixels  
Display aspect ratio                     : 16:9  
Frame rate mode                          : Variable  
Frame rate                               : 13.033 fps 
Minimum frame rate                       : 3.906 fps  
Maximum frame rate                       : 58.824 fps  
Color space                              : YUV  
Bit depth                                : 8 bits  
Scan type                                : Progressive  
Compression mode                         : Lossy 
Bits/(Pixel*Frame)                       : 0.617  
Stream size                              : 208 MiB (100%)  
Language                                 : English  
Encoded date                             : UTC 2012-04-29 18:18:23  
Tagged date                              : UTC 2012-04-29 18:18:23  

**Audio**
ID                                       : 2  
Format                                   : AMR  
Format/Info                              : Adaptive Multi-Rate  
Format profile                           : Narrow band  
Codec ID                                 : samr  
Duration                                 : 3mn 55s  
Bit rate mode                            : Constant  
Bit rate                                 : 12.8 Kbps  
Channel(s)                               : 1 channel  
Sampling rate                            : 8 000 Hz  
Bit depth                                : 13 bits  
Stream size                              : 367 KiB (0%)  
Writing library                          : pvmm  
Language                                 : English  
Encoded date                             : UTC 2012-04-29 18:18:23  
Tagged date                              : UTC 2012-04-29 18:18:23
Have you tried using Quicktime Pro version 7?  It's what I usually use for file conversions.  It costs about £20 / $30.

http://store.apple.com/uk/product/D3380Z/A/quicktime-7-pro-for-mac-os-x

Open your file.  

Go to the file menu, and select Export
Choose your format, e.g. Quicktime Movie with ProRes 422 codec at 30 fps.