Allows truncating a currently playing mpegts file.
File is NOT completely rewritten/copied/muxed/encoded. File is edited directly on disk.

Relies on fallocate as supplied with your system.
Uses fallocate with FALLOC_FL_COLLAPSE_RANGE, which is only available on Linux 3.15 (or later) on XFS or ext4 (extent-based files).
See https://man7.org/linux/man-pages/man2/fallocate.2.html.

Please note: The point at which the file is truncated is aligned to the nearest file system block size. The cut mpegts frame will be damaged virtually always. The rest of the stream should be fine.

I use this myself on files of recorded TV shows to remove advertisements from the beginning of the recording.

Copy mpegts_truncate.lua and mpegts_truncate.sh to your mpv script directory (usually ~/.mpv/scripts).

In case you prefer having mpegts_truncate.sh in your path, you can adjust mpegts_truncate.lua accordingly.

Use the shortcut Alt+Shift+f to truncate the currently playing MPEG-TS file up to the current position.

Use the shortcut Alt+Shift+b to truncate the currently playing MPEG-TS file at the current position.