Does anyone happen to have any code samples that would enable, even at a rudimentary level, video with sound on the PC engine?
As mentioned, Tom replaced some of the video in Gulliver (I think) about 17 years ago as a proof-of-concept. It was just 16-color video (easy to create), and I don't know if it contained audio.
Also many years ago, Mooz documented the important bits of the HuVIDEO format, and extracted the HuVIDEO data from all the games that use it. His work is available online.
https://silentdebuggers.com/doku.php?id=grafx:huvideohttps://github.com/BlockoS/YunaHuVideoI reverse engineered both the PCE's CD-ROM routines and HuVIDEO playback a few years ago, and asm source has been available for a year or two now, and an example of using it to play back Gulliver Boy's HuVIDEO using a TurboEverdrive is in my asm example projects directory in HuC.
There aren't public tools (yet) to create a HuVIDEO-compatible data stream, but there are folks working on that.
HuC is unlikely to ever be capable of playing back HuVIDEO because it's impossible to create a HuC program that has the 240KB of free RAM that's needed for the HuVIDEO buffering.
It will be supported in HuCC at some point, but it's not been a priority to get working because there's no homebrew HuVIDEO data to play back (yet)!