Before 2006, high-quality piracy meant “DVDRips”—grainy, standard definition, 700MB files. The introduction of Blu-ray changed everything. A "Br-Rip" in 2004 is anachronistic (Blu-ray launched in 2006), suggesting this specific encode is likely a later re-release of the 2004 film. But the label stuck.
For the user, "Br-Rip" meant one thing: No more artifacts. The source was a 25GB-50GB disc squeezed down to roughly 2-4GB. You could finally see the sweat on Alexander’s brow and the dust of Gaugamela without the compression blocks of a DVD. Why 720p and not 1080p? Alexander -2004- 720p Br-Rip -X264 - Ac3
Many scene rips of the time used MP3 audio to save an extra 100MB. AC3 (usually 5.1 channels at 448kbps or 640kbps) is larger. By including AC3, the creator of this file assumed the user had a surround sound system. But the label stuck