As this question has not really been answered yet: for the people who bought a 4/8GB Pi4: as far as this amount will never be useful for the emulators, would it be helpful to increase the VRAM to 2/4GB?
@bfollowell What video player option are you using in Emulationstation ? omxplayer, the HW accelerated option, has issues with some videos. If you switch off the hw accelerated video, do the videos play ok ?
I really didn't setup a player. I just put the media files in the individual ROMs folders, along with my gamelist.xml file, and the videos showed up and started playing. So, whatever player RetroPie uses by default, and however it is setup.
Actually, before I submitted this, I decided to go and check. I found OMX Player (HW Accelerated) listed under the Main Menu under Other Settings. This was off. I turned it on, and the videos for TG16 start much faster now. There is still a slight delay, but only about a second. I still have no idea why it's only this one system that exhibits this behavior, but I'm happy with it now.
I just want to say this works now. I can finally record how I play on this thing, which just refused to work before. I installed the newest firmware and tried it again. But since April (we have December now) a lot of things changed since then. If the above posting is a bit confusing, here is a brief explanation. I just have to switch a single HDMI output to be able to record.
The PVR Rocket is a portable device to record from any HDMI source up to 1080p30 or 720p60 to a usb drive. I usually use my RetroPie system with my old crt pc monitor at 640x480p. It is connected with a HDMI to VGA converter and all boot and emulator settings are optimized for that. The recordings are saved at 640x480p at 60 fps.
Recording: The HDMI output from Raspberry Pi is connected to the input at PVR Rocket. Then the PVR Rocket have also an 0 delay pass through HDMI output, which is connected to my final monitor. A single button press starts the recording and a second press stops it whenever I want.
Playing without recording: The HDMI output from Raspberry Pi is connected to a VGA splitter. That VGA output is connected to my final crt pc monitor. To get sound, the VGA splitter will output 3,5mm audio jack.