Just tried it, and it made spasm crash. I'm just going to merge the pages and sign manually from now on. Is there a way for spasm to pad a .bin output file to 16kb?

Assuming you're using the normal page addresses ($4000-$7FFF), you can put .block $8000-$ at the end of the source to pad the page.

Update time!

Spasm has been very uncooperative, so it is now relegated to assembling the first page of the app, and I have put together some scripts to piece together the rest and run rabbitsign on the result, so now you can see the full video. I also made the switch to 60Hz interlaced, allowing me to time the audio better when I implement it. This has the side effect of making the GIF look very ugly, but it shouldn't be as noticeable on a real LCD with display blur. (Suggestion for Wabbitemu devs - instead of trying to detect grayscale and display the appropriate shade, simulate the LCD's motion blur.) If you run this on actual hardware, you should hear an A if you plug in speakers, as a proof of concept that sound is possible alongside video. I also have in the works better compression, by switching between RLE-encoded full frames and p-frames (stores changes from previous frame) encoded similar to this, as suggested by Juju. I already wrote the encoder and it appears to give a 30% reduction in size compared to only RLE, but I still need to write the decoder for it.

I didn't fix the sound glitch. It happens when using two sound channels and I disabled one of them in this version.

Tested the version linked to me on the IRC chan on hardware (TI-84 Plus SE).  The timing fix works, and the interlacing is less noticeable on the actual hardware. It's still obvious when the scene changes very fast, tho.

I've been making some progress on P-Frames. It's not quite ready yet, as you can see in this GIF:

I was also using interlacing in the previous GIF, but here it is much more visible as I had a bug that made the "upper" frames display on the "lower" scanlines and vice versa. I also fixed the problem last night, but forgot to upload the updated version, so here it is. There's no visual difference, but I managed to make the file size smaller.

I've added sound. Go ahead and try it in Wabbitemu or a real 83+/84+ SE, but be warned that it is horribly out of tune. There is also stuttering in the audio, but I can't tell if it is Wabbitemu or my code.