Homebrew Would outputting 3ds to composite be possible?

[ChaoticPumpkin]

Hey guys, I was thinking about this the other day, the 3ds has an audio jack, and there are 3.5mm jack to composite video cables, would it be possible to write homebrew to output composite to the headphone jack? Basically how the psp could output to the tv. I know it wouldn't ever be as good a capture card mod, but it (theoretically) would have better/more stable framerate than NTR's output over wifi. I don't know a lot about what homebrew has/hasn't got access to, any info would be appreciated!

 

[IC]

It would only be possible with a complicated hardware modification, similar to installing a digital capture card. The headphone jack on the 3DS is only connected to the output of the sound chip, and the sound chip would not be able to generate a video signal.

 

[ChaoticPumpkin]

It would only be possible with a complicated hardware modification, similar to installing a digital capture card. The headphone jack on the 3DS is only connected to the output of the sound chip, and the sound chip would not be able to generate a video signal.

I was worried about that, but I thought I'd ask anyway for people that know more than me °o°

 

[IC]

I was worried about that, but I thought I'd ask anyway for people that know more than me °o°

If you really wanted to make some crazy software project out of this, you could probably make the 3DS output a very bad video signal as audio from the headphone jack that would require an external video decoder. Take a look at this video, it's possible to have very low quality video on a vinyl record played through normal vinyl record players:

Obviously this will give you light years worse quality than streaming with NTRCFW, and it probably wouldn't be possible to run it in the background with actual games because of the required processing, but at least you could tell people that your 3DS is outputting video from the headphone jack.

 

[Jayro]

Why doesn't Luma CFW just integrate NTR's features? That would give you the best of it all.

 

[Supercool330]

Why doesn't Luma CFW just integrate NTR's features? That would give you the best of it all.

I was literally looking at this a couple hours ago. Apparently PabloMK7 looked at doing this at one point, and couldn't get it working. Here's the source relevant source from NTR if anyone wants to take a crack at it: https://github.com/mariohackandglitch/NTR/blob/master/source/ns/ns.c

It may also be doable in a CTFPF plugin for the 3GX fork of Luma.

 

[Jayro]

I was literally looking at this a couple hours ago. Apparently PabloMK7 looked at doing this at one point, and couldn't get it working. Here's the source relevant source from NTR if anyone wants to take a crack at it: https://github.com/mariohackandglitch/NTR/blob/master/source/ns/ns.c

It may also be doable in a CTFPF plugin for the 3GX fork of Luma.

That's a shame, because if it could be working, and especially without breaking with each OFW update, that would be killer.

 

[Supercool330]

Honestly, it really shouldn't be that hard, just grab the bitmaps, encode them, and send them over a socket. I suspect that the approach that NTR CFW is taking isn't actually ideal, it just JPEG encodes the bitmaps individually and sends them across. This is maybe quicker than actually encoding video, and it definitely makes the code simpler, but you might be able to do better using an actual video codec like AV1 or even just using a better image codec like JPEG XL. The problem is that you only have a few cores (probably 2 at most) and no NEON instructions, so everything has to be done in software. It might be interesting to just port the approach used in NTR, but make it more modular so that different encoding techniques could be experimented with (which would also be a lot simpler if it was a plugin instead of a bulit-in part of Luma/Rosalina). Thinking about it, there are a number of parts of Luma that could potentially be broken out into plugins already like the Cheat Engine and input redirection.