Game and video backups are copies of an UMD that are in the standard image format. (ISO) You can perform a backup of any disc that is on M33 firmwares.
Structure of Game Backups
With all UMDs, there are a required firmware to be installed on your PSP in order to play it. If that firmware requirement is not met, the disc will not be able to be used on that PSP until upgraded. Any UMD game will consist of a 'SYSDIR' folder, an 'USDIR' folder, and a 'UMD-DATA.bin' file within the folder. Game backups can consists from anywhere between 500MB and the max 1.8 GB.
This folder, short for System Directory contains files for the firmware update for the PSP. This allows firmware updates to be performed directly from the disc. This usually takes about 15-27MB in size depending on the update.
This contains all of the game files. This usually takes the most size of the backup.
File needed for the firmware requirement among other things.
There are many ways to obtain a backup of any image. However, the better the disc, the better and faster the backup. On earlier SE/OE firmwares, homebrew was required to obtain a backup of an UMD through a dump to the memory stick. This process usually went well unless the memory stick is extremely slow, or went into corruption due to lack of space for the backup.
On the newer M33 firmwares, there has been an option to directly rip UMDs via USB. This method was more useful, but at the cost of your computer's memory, and space, it can sometimes prove costly for a while. To perform a backup via this method, you will have to boot into the XMB, and open up the vshMenu. From there, go down to the 'XMB USB DEVICE' option, and press left once to make it say 'UMD Disc'. From there, exit, and pop in an UMD. When it is recognized by the XMB, make a USB connection. When the connection is active, copy and paste the 'UMD9660.iso' file under the mounted drive to a selected directory on your computer. This process can yet again take 15-30 minutes depending on size, and the quality of the disc.
Ever since 1.50, there has been different methods implemented to mount the backups and run them at full speed. Over time, the most popular ways of mounting has been using through Team M33's No-UMD Driver which is present after 3.51 M33-4, and Sony's official NP9660 drive available fully since 3.52 M33. Both are highly effective methods to play backups.
If you have a new memory stick for any firmware, it is recommended to format your memory stick via the PSP to create the proper folder format. This will help out with organizing your data on your memory stick. Once you have obtained your backup, go to the directory where it is ripped. If it is on your memory stick, find it. You want to rename it to something that you want to remember. Keep it short, and under 20 characters. Anything higher, and the backup will go unrecognized by the PSP. Also, remember to keep the .iso extension (if any) at the end of the filename to keep it in ISO format. When done, transfer the file to ms0:/ISO. If it is a video, transfer that to ms0:/ISO/VIDEO.
Mounting for Play
On the newer M33 firmwares, there is no further instruction other than to mount your video backup or launch it. To launch any game backup, you must have the proper configuration set in recovery or the vshMenu or the game will fail to load. On the vshMenu, bring it up. Go down to 'ISO MODE'. Press right to 'M33 Driver' or 'Sony NP9660'. If you have a video backup to mount, go down to 'ISO VIDEO Mount', and press right until it displays the video you want. From there, exit the vshmenu.
Note: You can only mount a video from the vshMenu. Make sure it is enabled in recovery.
When done, go to GAME>MemoryStick. In the game listing, choose the game/video and launch it normally. The game/video will play like any other, and you will have full control of it, just as an ordinary UMD.
Note: You can decide not to set any ISO mode. As long as an UMD is in the drive, the backup will play.
Note: Also, on 3.80+ firmwares, the Sony NP9660 loader has been optimized affecting gameplay, and memory stick loading. You may experience slow-downs during play. The most affected factors are .cso files, and a 4 GB formatted to FAT32 format.
Backups just like any other image can be compressed or have some files dummied or relinked to free up space. However, this may take away some of the game experience. There are various tools such as Yet Another CSO Compressor (YACC), and UMDGen. In Addition, you can take an untouched image, and use a ripkit to rip specific aspects such as the UPDATE files, excess dummy padding, and movies.
In Addition to the manipulation, an image can be compressed to allow more space at the expense of speed, and gameplay. The available formats are the standard compressed image, (CSO), Dark_Alex's compressed image (DAX), and Uncle_Jams' JISO file. However, DAX, and JISO formats are rarely used due to CSO being more popular, and no available tools that are able to run on the newer firmwares to launch DAX and JISO files. Standard tools like YACC and UMDGEN are able to compress, uncompress and recompress through the different formats.
Action taken by Sony
With the backups obtainable from the discs, it has led to pirates distributing games and videos throughout the internet via bittorent and p2p. In this process, Sony loses a lot of money everyday from pirates, and has started to release firmware updates disguised as patches to fix the ability to be able to rip and share. Also, there is security in PSN titles that prevent them from being shared.