There have been some mpegts parsing optimisations accepted in upstream
ffmpeg. 
They reduce mpeg2ts parsing time by about 20% on the Pi. All platforms
should benefit.
This improves startup time and playback for high bitrate m2ts/iso files.

Commit Summary

[ffmpeg] - backport - avio: Add an internal function for reading without
copying
[ffmpeg] - backport - mpegts: Remove one memcpy per packet
[ffmpeg] - backport - mpegts: Make discard_pid() faster for
single-program streams
[ffmpeg] - backport - mpegts: Remove one 64-bit integer modulus
operation per packet
[ffmpeg/patches] Add backported mpegts optimisations