This refers to stereo sound. While it doesn't offer the immersive experience of 5.1 surround sound, it is ideal for viewers using headphones or built-in laptop speakers, further reducing the overall file size.
This indicates the source material. A BrRip is encoded from a retail Blu-ray release, ensuring the highest possible baseline quality, superior color depth, and fewer compression artifacts compared to TV airings or web streams. Breaking-Bad-Season-2-720p-BrRip-2CH-x265-HEVC-PSA