I recently made 23 of my best stereoscopic videos available on USB 3.0 flash drives for direct plug-and-play on 4K and HD 3DTV's (OU vertically squished format). I have now added a SxS 3840x1080 version of each show for 4K phones (or other 3840 wide SxS displays). These SxS shows, as well as the other formats, are available for download. For details please visit hart3d.com and click on the yellow Video Collection button.
NOTES FOR PLAYING ON SONY XPERIA 4K PHONES (e.g. Z5 Premium, XZ Premium):
Normally I copy the SxS.mp4 video file(s) to the phone's internal memory (movies folder) and play them using the phone's own Video App. The play is smooth and with full 4K resolution. These phones take external micro-SD cards. Thus, you can add storage to the available internal capacity (which is only about 48GB for the XZ, less for Z5). However, the android operating system for these phones only seems to support Fat32. This means that only shows <4GB in size will work in the external memory. I tested a 32GB V30 Sandisk card, and it worked fine for movie-play in the phone, but I had to format it to Fat32 first (NTFS and exFAT failed).
PS - anyone who previously bought the flash drive version can get a free download link-list. Email me.