It looks like you’re looking for a guide on 300 MB MKV movies

Compression & Codecs: To achieve such a small size (standard HD movies are usually 2 GB to 8 GB), these files use aggressive compression . Modern files often use the AV1 or HEVC (H.265) codecs, which provide better quality at lower bitrates than older formats like H.264 .

A. Codec: HEVC (H.265) over H.264

Older 300 MB rips used x264 (H.264) with low bitrates (300–400 kbps), resulting in blocky, soft images. Modern 300 MB MKVs leverage HEVC (H.265), which achieves 50% better compression than H.264 at the same perceptual quality. Some cutting-edge releases even use AV1, though decoding it on low-end hardware remains a challenge.

Standard high-definition (HD) downloads typically range from 2 GB to 4 GB. Achieving a 300 MB file requires heavy compression, which may result in a loss of fine detail compared to larger formats. or more details on different video codecs