Q: Why can't I Import some .avi and .mp4 video files into Vegas Pro or Vegas Movie Studio ?
Answer: Not all .avi and .mp4 videos are the same and some use Video Codecs that are not supported by Vegas Pro and Vegas Movie Studio software.
A .avi or .mp4 video file is actually a generic Video Container for many possible Video Codecs.
.avi and .mp4 are two of the most generic video file extensions (video containers) used for saving videos to and are definitely not all the same.
There are a lot of different video codecs in use and Sony Vegas cannot decode them all. Software companies need to pay a licensing fee to the makers of some Video Codecs, if they are included as part of a program. If every video codec known was included in Sony Vegas and Movie Studio, it would add greatly to the cost of buying the program, so that is why some videos cannot be imported.
Examples of some formats/codecs that Sony Vegas and Movie Studio cannot read are DivX and Xvid. Flash Video which ends in .flv will also not work in Sony programs.
Solution - Using Handbrake to convert videos that won't open in Vegas
Convert your video files into a more common video codec that Vegas Pro and Vegas Movie Studio can read easily or record your original video files using a codec/format that Vegas already likes.
In 2021, I highly recommend the program Handbrake to convert any videos that don't work in Vegas Pro or Vegas Movie Studio.
Handbrake is a high quality video encoder, that will not degrade your video quality during transcoding.
I have a complete beginners guide tutorial for how to use Handbrake here:
How to use Handbrake 1.1.1 - Beginners Guide for Exporting Video
Another important thing to do before you start using Sony Vegas or Movie Studio for the first time, is to install Apple Quicktime for Windows. Vegas Pro and Movie Studio need Quicktime so that they can read and write particular sub-sets of video codecs.
Important Update for Windows 10/8.1/8.0 users and Installing Apple Quicktime
Apple has decided to spoil the fun of upgrading to Windows 10 and have added some code to the latest Quicktime version, which makes it impossible to install on a Windows 10 or Windows 8/8.1 computer. This may change in the future, but for now you will have to install an older version of Quicktime.
My suggestion is that you download and install version 7.7.6 from this page on the Apple website.
File Formats/Codecs that Vegas Pro Likes
Imports: AAC, AA3, AVI, BMP, MPEG-1, MPEG-2, MPEG-4, WMV, HEVC, ProRes, AAC, AIFF, FLAC, LPEC, MP3, OGG, PCA, W64, WAV, WMA, BMP, JPEG, PNG, TIFF, WDP, WMPhoto, DDS, DPX, EX, AAF, Premiere/After Effects (*.prproj), Final Cut Pro 7/ DaVinci Resolve (*.xml), Final Cut Pro X (*.fcpxml), EDL Text File (*.txt), Broadcast Wave Format, DVD Camcorder Disc, Closed Captioning
Exports: AAC, AA3, AVI, BMP, MPEG-1, MPEG-2, MPEG-4, WMV, HEVC, ProRes, AAC, AIFF, FLAC, LPEC, MP3, OGG, PCA, W64, WAV, WMA, BMP, JPEG, PNG, TIFF, WDP, WMPhoto, DDS, DPX, EXR, VEGAS Project Archive (*.veg), Pro Tools AAF File (*.aaf), Media Composer AAF File (*.aaf), Premiere/After Effects (*.prproj), Final Cut Pro 7/DaVinci Resolve (*.xml), Final Cut Pro X (*.fcpxml), EDL Text File (*.txt), XDCAM Disc
File Formats/Codecs that Vegas Movie Studio Platinum Likes
Imports: AAC, AA3, AVI, BMP, MPEG-1, MPEG-2, MPEG-4, WMV, AIFF, FLAC, MP3, OGG, PCA, SND, W64, WAV, WMA, GIF, JPEG, PNG, WDP, CDA, SFA
Exports: AVC/AAC, AVI, MPEG-2, MPEG-4, WMV, MOV, AVCHD, RM, MVC, XAVC S, AAC, AIFF, FLAC, LPEC, MP3, OGG, PCA, W64, WAV, WMA, BMP, JPEG, PNG, TIFF, WDP, WMPhoto, DDS, DPX, EXR