3657-br720p-subs-insidious4.mp4

: Indicates the source material is a Blu-ray disc, suggesting high-quality video and audio compared to "CAM" or "DVD" rips.

Based on the file naming conventions typically used in digital media sharing, 3657-BR720p-SUBS-INSIDIOUS4.mp4

: The video resolution (1280 x 720 pixels), which is standard High Definition (HD). : Indicates the source material is a Blu-ray