Maybe you've got a horror game project and want to have some funky images encoded in audio for players to decode?
Then this is the chost for you!
This isn't going to get in-depth about what SSTV is or how it works or any of that - this is just going to be a basic rundown of how you, with nothing but your computer and some free software, can make SSTV signals of your very own and decode them just as (if not more) easily.
Setup first.
We're going to need two programs here:
- For Windows users, you're going to need MMSSTV. This is the core of using SSTV stuff on your computer. Similar programs exist for Linux and Macintosh systems, but I'm not familiar with them and lack any devices with those operating systems to use for this purpose, so we're going to be glossing over that.
- You're going to need an audio recording program that can capture your speaker output. For this, I'll be using Audacity.
That's it! That's all you need for this, program-wise anyway. Now...
The Test Subject
First and foremost, we need an image to encode. For that, I've "volunteered" this eggbug. Don't worry, it'll be perfectly safe. Mostly. I think.
Isn't it adorable?
MMSSTV - Step One - Preparing the Chamber
So, once you've got the program installed and opened, you're going to want to go over to the "Template" tab up at the top. There'll probably be a bunch of things in there already - text and whatnot. Left-click these to select them, then right-click them and just delete them. It's that easy. Your window should look something like this:
Step Two - Inserting the Subject
The easiest way to do this is to simply copy the image you want to encode to your clipboard, and then right-click in the image area within the program's window. There's an option labelled "Paste Image" which rolls out two options - bitmap and overlay. For our purposes, let's use overlay.
Now, let's insert our precious eggbug and...
Look at them! Snug as an eggbug in a rug, no sweat. Let's move on.
Step Three - Transmission and Recording
You're gonna want your recording software ready, here. Make sure it's set to take input from your speaker output, or whatever device you set MMSSTV to output on.
In the MMSSTV window, switch tabs from Template over to TX. There's a button with red text on it that says TX down below the image area now - but DON'T press this yet. Go over to your recording program of choice, hit the record button, and then hit the shiny red-text TX button. Make sure to stop recording once it's done scanning across the image. No visual aid for this part, sorry - it's a pretty cut and dry thing, and I can't exactly see what recording program you're using over there.
Step Four - Receiving
This is the fun part - getting to see how it came out. Swap tabs over to RX and play the audio file you just generated, or one sent to you by a friend. Make sure MMSSTV's audio input is set to be from your speaker output, stereo mix or what have you.
Looks like our intrepid test subject came out with some very light distortion. That's to be expected, they were just turned into audio and back. If you want to increase the distortion, try layering the signal with some white noise!
Have fun!