PSP File and directory structure conventions
From The Neuros Technology Wiki
Filename and Directory structure considerations:
The PSP will not recognize videos that aren't named according to a very sepcific convention. Here is a short list of instructions to make sure you have the right folders set up on your Memory Stick.
*Put your memory card into the PSP. *Use the PSP to format the memory card. *On the PSP, put it into USB Connection Mode. *Use the PSP - USB cable to connect it to your computer. *Find the drive letter that your PSP was assigned. Here we will assume your PSP is E:\. *On the PSP's drive letter (not in any folder, simply on the drive), create a folder "MP_ROOT" . *Create a sub-folder named "100MNV01" in "MP_ROOT". *Create a sub-folder named "100ANV01" in "MP_ROOT" *Now, any MP4-SP files you create, put into the 100MNV01 folder. Any MP4-AVC files, place in the 100ANV01 folder. *For movie files to be visible to the PSP, they must be named according to the following convention: *MP4-AVC Files must be named: MAQ#####.MP4 where ###### are numbers. *MP4-SP Files must be named: M4V#####.MP4, as above.