Complex sentence: In April 2012, the 16:9 resolution of 1366 × 768 became the most commonly used resolution worldwide; the previous most common resolution was 1024 × 768 (4:3).
Split into simpler sentences: In April 2012, the 16:9 resolution of 1366 × 768 became the most common used resolution worldwide. The earlier most common resolution was 1024 × 768 (4:3).