Topic: PlayStation BCA mark/barcodes, and reading ringcodes from black discs
Which format is the barcode around the ring? It looks like a Code 39 variant, in that there are only narrow (1 pixel) and wide (3 pixel) lines and spaces, except that they make no sense when put together (e.g. it's not A-Z/0-9 characters, merely binary data). Additionally, each wide bar is preceded by a narrow space; each narrow bar is preceded by a wide space. PS2 CD-ROMs also have a second barcode in the ringcode area which isn't present on PS2 DVDs.
Or are the spaces ignored entirely with narrow bars being 0 and wide being 1? With no spaces, CDs are 104 bits long, DVDs are 108 bits long. The second barcode (PS2 CDs only) is 28 bits long.
I can't find anything on Redump about the PSX BCA mark or whatever it is called. The same barcodes are also on PS2/PS3 and even audio CDs and DVD videos, anything on Sony-pressed discs.
Edit: There are ringcodes on regular black-backed PlayStation CDs! To be able to read the ringcodes of non-Platinum discs (e.g. the majority of PlayStation games out there), you will need any device capable of "red" light output (or orange, yellow etc). For example, incandescent bulbs (lamps, flashlights etc.), infra-red light (e.g. remote controls) or even sunlight. Digital image capture devices can see infra-red light, thus pointing even a TV remote's infra-red LED at the disc should show up on your camera. It may take a while to find the data, but it should show up as black numbers on a solid red background - the inverse is true about the barcode.
Alternatively, if you have a powerful enough light source and a scanner, you can simply shine the light straight through the picture side of the disc while scanning, however the mould SID code may not show up in the scan due to the amount of light. It is advised to shine the flashlight from an angle, so the light doesn't overpower the scanner and whitewash everything (sitting the flashlight right on top of the disc made my scanner show a glitched area over parts of the ringcode, making the image useless).
Light which uses the blue spectrum (e.g. "white" LEDs and flourescent lights including CFLs) will not work.