What I found out:
- GDR-H20N: Full ×16 reading speed on pressed CSS DVD-Video.
- Recordable media: Not dependant on contents. R at best ×12, RW at best ×8, R DL at best ×8.
- S182: ×16 error scans but only ×8 data reading speed on pressed DVD-Video, with and without CSS. Speed limit ×8 maintained until next eject, even for error scans, after starting DVD playback.
- GDR8162B: ×16 for pressed software DVD-ROM, ×8 for pressed DVD-Video, even without CSS. Speed of recordanle media varies but independent from content (×8 R, ×4 RW at best).
- DualLayer pressed VideoDVDs: ×4 with CSS (without CSS =untested) while ×12 for software DVD-DLs without movie content.
- LG BE14NU40 on pressed DVD, DVD-R and DVD+R:
- ×16 without movie.
- ×12 for all movie DVD. Also without CSS. Jamless play related?
- WriteMaster H653B (has no (W)riteMaster logo): Always full speed ×16 on +R,-R and pressed DVD’s, even with CSSvideo.
In cases with ×12 limitations, mixed DVDs with both Video_TS and software files were also limited.
I will have to do some testing: Different file systems, folder locations, blank VIDEO_TS, etc. to see, how the software detects these limitations.
What does explain these seemingly additional irrational software-based speed limitations?
Are DVD-ROM and DVD-Video not physically identical other than contents and maybe slightly different manufacturing process?
BE14NU40 reached full ×16 reading speed and maintained the full speed until the very end, on an old data DVD-R, with over 1000 PIErrors on average due to underspeed recording and scratches.