She downloaded it in four minutes. No malware. No pop-ups. No half-finished copy where the train scene glitches out.

That night, she watched Keira Knightley glide through Joe Wright’s theatrical, dreamlike Russia. The ballroom scenes were crisp. The colors held. And when Anna threw herself under the wheels—Lena understood why people still read Tolstoy.

Knowing the right file format can save you from two hours of pixelated misery.