What is the difference between x264, tMod, and kMod builds?

[orion44]

What is the purpose of tMod and kMod custom builds? What are they optimized for?

Which one would you use for backing up Blu-ray movies?

[Selur]

Thanks to the forum search: What different between x264 offical, kMod, tMod (https://forum.doom9.org/showthread.php?t=164506)