PSP Release: Xerpi ports udcd_uvc to the PSP allowing one to stream its screen to their PC, Mac and even Android device – Currently in PoC stage with a 20FPS framerate!

by Aurora · September 28, 2020

One of the staple plugins for the PlayStation Vita is xerpi’s udcd_uvc which effectively turns the device into a hybrid console allowing you to play games on the big screen as well. Now, the same developer is working on porting the plugin to the PlayStation Portable with a PoC plugin that outputs 20FPS already being available!

Xerpi ports udcd_uvc to the PSP

With udcd_uvc for the PSVita, you could stream the console’s screen to a PC, Mac or even Android device via USB with a recent update adding support for the latter two. Now, the plugin has been ported in PoC form to the PSP!

In May, xerpi added a GitHub repository called ‘psp-uvc-usb-video-class’ and mere hours ago, he released the first PoC (proof-of-concept) version of the plugin which is a port of Vita’s udcd_uvc. Like udcd_uvc, the PSP UVC Video Class plugin (which seems to be its official name) allows you to stream your PSP’s screen to a computer or smartphone via USB which translates into playing games on a bigger screen. This is done by effectively turning the PSP into a UVC (USB Video Class) device similar to a webcam thus allowing you to view its screen on your PC although it must be noted that no audio is streamed!

Streaming the PSP’s screen to a PC via USB is something that has been done before with Remote Joy Lite but this solution only works on Windows and can be problematic with some games.

Current state of xerpi’s plugin & future plans

According to its GitHub release page, the recently released plugin is a proof-of-concept as it does RGB->YUV conversion on the CPU. This results in a frame rate of about 20FPS @ 480×272 which is the PSP’s native resolution – obviously, this is not stellar but xerpi does have some improvements up his sleeve in order to improve performance!

Xerpi’s suggestion on how 60FPS could be achieved if CSC conversion is reduced to 16.667ms or less (from GitHub Release Page below)

The primary improvement is that of making use of the PSP’s VFPU, ME or VME in order to perform faster RGB->YUV conversion rather than the CPU with some functions such as ‘sceMpegBaseCscVme’ and ‘sceDmacplus_driver_0x9C492B9B’ looking promising for the task.

Xerpi also did some performance benchmarks with the PoC which resulted in the following numbers:

32.9ms to perform CSC (RGB->YUY2 conversion)
- If this is reduced to 16.667ms or lower, then 60FPS could be achieved through double buffering which would result in a one frame latency from capturing the screen to sending it via USB
16.1ms in order to send a 480×272 frame via USB
This results in around a ~20FPS framerate with this number being derived by using the formula “1s/(time to perform CS + time to send the frame)”

Conclusion

If you wish to try out xerpi’s PSP UVC Video Class plugin, you can grab the “prx” file from the link below and put it within VSH.TXT or GAME.TXT. Xerpi recommends using PotPlayer on Windows and mpv/mplayer on Linux for the best experience. As usual, it is imperative not to nag xerpi about ETAs for this plugin but he’s known to deliver so cool things may ensue soon