I have an idea for trying to create some sort of homebrew software which allows for video output through either the analog out port or the SD card slot, picked because both wouldn't require hardware modding of the 3DS.
My idea is for a 3DS capture method that's actually reliable on all systems, works without hardware mods, and preferably isn't locked to just the 3DS mode. It'd be a sort of middle ground in quality between a system with a fully modded board, but not with quite the same issues that tend to arise from wireless streaming methods (especially when it comes to frame rates on Old 3DS models).
Honestly I'd pick either the SD card slot with some sort of SDIO contraption, or the analog audio output (I prefer the latter, and you'll understand why). Both have pros and cons in my hypothetical idea:
SD Card pros:
- Way higher bandwidth capabilities
- Would likely be much easier to mod from a software perspective
Cons:
- SD Card slot is taken, which will mean either figuring out some way to pass the actual SD card through to the system, or simply being unable to use your SD card and anything on it AT ALL while capturing
- Would require creation of an entirely new device
- DS mode will likely have no clue what to do with it, making it extremely difficult if not impossible to use there
Analog port pros:
- SD card slot is still free
- Audio already goes through there (so it could be argued we're already halfway there?)
- Won't require any other hardware to be made or purchased
- Will be easier to get working in DS mode (the DS at least expects an audio port, but it likely has no clue about an SD card slot)
Cons:
- I have no clue how much data can be put through an analog audio out (probably not very much though)
- This also means that any video output will probably be rather compressed (although honestly I'm not trying to get the most raw uncompressed video out of the 3DS anyway)
- Audio port will be completely unusable while capturing
The absolute minimum data throughput for something usable seems to be 1.5-2mbps, and something preferable will be closer to 4mbps or higher (yes I know you'd need a lot more to get the "full" quality, but that's not really what I'm looking for here. Just something usable). I've had this idea for a while, so I figured I'd share it. I went searching and couldn't find out if this had ever been tried or even suggested before. I'm not going to pretend like the idea will be easy (especially with the analog out port, as most computers can't just detect audio through a line in, which means some sort of even just basic software would also need to be developed so that the computer will know that it's not just white noise or something).
The most difficult part though is how to basically trick the 3DS to output something like this through that port. That's not to say it's impossible, as obviously we're able to do this over wifi. The even more difficult part would be trying to get the DS mode to play along. I think it'd be interesting to see, especially given the fact that 3DS capture boards seem to be getting more and more rare and/or expensive, and to me the wifi option is...not the most fun to use, from both a viewing and a usability standpoint.
If people find this interesting I might move this to it's own separate thread.