You can play .mp4 video files on PSP. But notice that : there’re two kinds of .mp4 video files:

1. Normal .mp4 video files,which can be played on any PSP.
2. AVC(H264) .mp4 video files,which can only be play on Version 2.0 or up PSP directly,
   or on Version 1.5 PSP which is upgraded to Version 3.xx.
   

Now let’s see how it is done in detail:

Step 1 Install “Version 3.40OE-A self-upgrade”.

1. Download Version 3.40OE-A self-upgrade (Click here to begin)
Extract it on your hard disc.

2. Turn on your PSP and go to “System setting”, select “Format Memory Stick” to remove unnecessary data from your memory stick. Notice:Backup your data before you do this!

3. Keep your PSP on and go to “USB Connection” ,connect your PSP to your computer with a USB cable.

4.(For Version 1.5 PSP users) Copy “340oeflasher” and “340oeflasher%” to folder “/PSP/GAME” on your memory stick.
(For Version 2.71 Se or 3.xxOE users) Copy “340oeflasher” and “340oeflasher%” to folder “/PSP/GAME150” on your memory stick.

5. Run “3.40OE-A Firmware Install” in “Game->Saved Data Utility” on your PSP. Make sure the battery volume is 75% or up,otherwise the program would end up with an error.
You can skip the battery check by pressing “△” and “L” button when start the program.

6. When the red words appear and hold still, press “X” and begin the installation.

7. When the installation is done, there will be a note says “Done. Press X to shutdown the PSP. restart manually！”. Press “X” button to shutdown the PSP, restart it manually to complete the installation.

Step 2 Load your PSP with .mp4 video files.

You must rename your .mp4 video files right:

1. For normal mp4 video file, the name must be M4Vxxxxx.MP4
2. For AVC(H264) .mp4 video file, the name must be MAQxxxx.MP4

(xxxxx is for any 5- digital number. For example: M4V00001.MP4 or MAQ00001.MP4)

You must put different kinds of files in different folders:

1. For normal mp4 video file, put it in “MP_ROOT\100MNV01\” folder
2. For AVC(H264) .mp4 video file:
   if the resolution is 480x272 in “MP_ROOT\100ANV01\” folder;
   if the resolution is 720x480 in “VIDEO\” folder.

Step 3 Play the video files on your PSP.

Get back to the PSP main menu and select “VIDEO->Memory Stick” to play the video files.
Press “△” to get help on how to operate while playing the video files.