I think there is no need to introduce DosBox. And to make it even more usable DosBox developer niknamed Harekiet added screen output recording capability with his own codec ZMBV – Zip Motion Blocks Video.
This codec employs intraframes and motion compensation (and XOR’ing instead of substracting/adding difference). ZLib is used for packing. For more detailed description go
here.
For now, 8-bit, 16-bit and 32-bit depths are supported by codec as for recording. And FFmpeg decoder is already available – I could not miss that codec and not port it.