Youtube premium opus 251kbps vs Youtube music mp4a/aac 141kbps

This string selects or describes an Opus audio stream (ID 251, codec opus) combined with an experimental video track av01008m08 , track ID 399, marked as new .

identifies a specific AV1 profile designed for versatility. The "08M" designation typically refers to a Main profile with an 8-bit depth, a common standard for consumer-grade streaming that balances visual quality with hardware compatibility. AV1 was developed to provide significantly better compression than its predecessors, such as VP9 and H.264. By utilizing advanced coding tools like intra-block copy and sophisticated film grain synthesis, AV1 can maintain sharp details and smooth gradients even at lower bitrates. This efficiency is critical for maintaining 4K or 8K resolution in environments with fluctuating internet speeds. Opus: Precision in Audio Delivery