There is no legitimate or safe public file index for downloading Jack the Giant Slayer (2013)

However, torrenting also has its drawbacks:

(the internal data structure that enables seeking and playback), you can often fix it using a media player: VLC Media Player : When opening a corrupted file, VLC may offer a "Build index then play" option. To make this permanent for all damaged files, go to Tools > Preferences > Input/Codecs "Damaged or incomplete AVI file" "Always fix" Stellar Repair for Video