It's slowly moving towards the official release. But it's not ready yet. This installer, as well as Splash 3.0.2 (Beta) itself, is very buggy.
It appears the program has been rewritten for the new engine, but some functionality hasn't been implemented. I'll describe the most significant regressions here.
1. This installer doesn't trigger a UAC elevation prompt and throws an error when trying to save the first file to Program Files. You have to manually right-click the EXE file and select "Run as administrator."
2. Huge problems with deinterlacing. It doesn't work with most tested files. Splash 2.7 worked perfectly. Splash 3.0.2 enables deinterlacing for .MPG files (MPEG-PS, MPEG-2 codec, SD), but not for .MTS files (MPEG-TS/BDAV, AVC codec, HD). It also doesn't enable it for .TS files (DVB). This is a very serious regression. In the program settings, "Deinterlacing: Auto" and "Automatic interlacing detection" are selected, and there's no other way to force correct playback. The result: horizontal interlacing lines in the image.
3. Aspect ratio regression. It can't display SD video in a 16:9 aspect ratio. It flattens it horizontally. It also can't interpret aspect ratio in SPS/VUI, which breaks the dynamic switching between 4:3 and 16:9 formats in SD files. It seems that it doesn't actually handle aspect ratio at all, but assumes that pixels are always square. Splash 2.7 worked perfectly. Strangely enough, the SmartSeek preview has the correct aspect ratio.
4. Very strange behavior when switching from windowed mode to fullscreen. For a few frames, the image appears in a different aspect ratio (e.g., a 16:9 video on a 16:9 monitor is briefly vertically flattened – black bars are visible at the top and bottom).
5. No support for 4:2:2 chroma subsampling. This is now standard in high-end cameras. Splash flashes various colors for a second and then shuts down. VLC works perfectly.
6. Problems displaying videos at high frame rates when the monitor's refresh rate is lower. 100/120 FPS in Splash is very choppy. However, VLC Media Player plays it smoothly, simply dropping frames that the monitor doesn't have time to display.
7. No support for the WEBM container.
There are more issues, but I've covered the most important ones for now. I'm waiting for the next version and will test it again.