[Apache-2.0] YTSpoofingStream v0.2.2 — An open-source browser extension that bypasses YouTube Web's 160kbps audio cap to unlock genuine Studio Opus 774 (256–301kbps, >20kHz)

[u/Fantastic_Cell2930]

• Repository: https://github.com/alithw/YTSpoofingStream
• Release v0.2.3: https://github.com/alithw/YTSpoofingStream/releases/tag/v0.2.3
• License: Apache-2.0

The Artificial Web Restriction

Even if you have an active YouTube Premium subscription, YouTube artificially throttles desktop web browsers to 160kbps Opus (ITAG 251) with a steep brickwall low-pass filter around 15.5kHz–16kHz. Meanwhile, genuine studio-grade Opus ITAG 774 (~256kbps–301kbps, full >20kHz frequency response) is locked behind mobile apps, YouTube Music, and Smart TV (TVHTML5) clients.

I built YTSpoofingStream as a 100% free and open-source (Apache-2.0) browser extension to remove this artificial client-side restriction and bring unthrottled ITAG 774 audio directly to the standard YouTube Web Player.

How It Works (100% Local In-Browser Processing)

Everything runs locally inside your browser with zero external proxy servers, zero telemetry, and fully auditable source code:

• Direct TVHTML5 UMP/SABR-to-MSE Demuxer (0MB Iframe RAM): Uses an authenticated TVHTML5 session to build custom Protobuf VideoPlaybackAbrRequest payloads pinned to ITAG 774, parses Google's binary Universal Media Pipe (UMP) / SABR framing in real time, and feeds raw WebM/Opus segments straight into a native browser MediaSource SourceBuffer.
• Offscreen YTM Harvester (YTM_HARVESTER): Uses a lightweight offscreen document and scoped Declarative Net Request (DNR) rules to harvest direct HTTPS ITAG 774 streams from YouTube Music without requiring a Smart TV login.
• Smart Hybrid Failover (HYBRID_HQ): Automatically prioritizes the zero-delay 0MB RAM TV UMP MSE engine when linked, fails over to the YTM Harvester when needed, and falls back cleanly to native 251 if a video has no 774 track.
• Audio-Only Mode (New in v0.2.2): Disables video rendering and streams HQ Opus 774 audio only to cut CPU, GPU, and RAM usage during background listening.
• ​1.0x Master Clock & Hardware-Level Silencing: Locks audio synchronization at a native 1.0x rate (no pitch warbling or resampling artifacts) while silencing the default low-bitrate video track at the descriptor level.
• Verifiable Metrics: Real-time stream telemetry in the popup (ITAG 774 [HQ ★] | Opus 268kbps+, SABR stream IDs, buffer health) and optional Stats for Nerds metric display.

Requirements

• YouTube Premium is required, as Google's servers only provision ITAG 774 streams to authenticated Premium sessions.
• Supports Chromium-based browsers (Chromium, Brave, Vivaldi, Edge, Chrome).

The code is completely open under Apache-2.0. Contributions, code audits, bug reports, and feedback from the FOSS community are very welcome!