Is the word ouviu the same in Brazilian and European Portuguese?

Yes

The word "ouviu" is identical in spelling, meaning, and grammatical function in both Brazilian and European Portuguese. It is the third-person singular of the verb ouvir (to hear) in the pretérito perfeito do indicativo (past tense). The only difference is in pronunciation. In Brazilian Portuguese, the vowels are typically more open and the rhythm is more melodic and syllable-timed. In European Portuguese, vowels—especially unstressed ones—are often more closed, reduced, or even "swallowed," which gives the language a more consonant-heavy, stress-timed sound.

Brazilian Portuguese usage:

1. Você ouviu o que eu falei? (Did you hear what I said?)
2. Ele ouviu uma música muito legal. (He heard a very cool song.)
3. Ela ouviu o barulho do carro. (She heard the sound of the car.)
4. Ninguém ouviu o aviso. (No one heard the warning.)
5. O cachorro ouviu o dono. (The dog heard the owner.)

European Portuguese usage:

1. Tu ouviste o que eu disse? (Did you hear what I said?)
2. Ele ouviu uma música muito fixe. (He heard a very cool song.)
3. Ela ouviu o barulho do carro. (She heard the sound of the car.)
4. Ninguém ouviu o aviso. (No one heard the warning.)
5. O cão ouviu o dono. (The dog heard the owner.)