1. MPEG4 or MPEG-4 stands for Moving Picture Experts Group V4. It  compresses video and audio, based on mpeg-1 or mpeg-2 and other related technology such as AAC (Advanced Audio Codec) and DRM (Digital Rights Management).

To convert mpeg4 to avi: The containers such as mp4, mov, avi, rm, mkv, ogm divx supports mpeg-4 stream. please install the appropriate video filter  and audio filter for the mpeg4 format such as FFDshow, divx, xvid, HDX4 codec, or MainConcept decoder.

Please install the avi video or audio encoder such as DivX, XviD.

Launch Open Video Converter, click the Open Video button, select an mpeg4 file for mpeg4 to avi.

2. PSP is PlayStation Portable developed by SONY company. It is a small device to play game, multimedia, still image, video and audio. PSP supports jpg, gif, bmp, png, tif, MP3, MP4, AAC, ATRAC, WAV, MPEG4.

Converting PSP to avi means to convert mpeg4 AVC video files to avi normally. Please install PSP filters such as mp4 splitter, or HDX4 player.

3. If the conversion failed, please try to use for converting MPEG-4 to AVI.