vrc-video-proxy

日本語

A drop-in replacement for VRChat's Tools/yt-dlp.exe. It resolves the URLs VRChat passes in using your own copy of yt-dlp, and returns them in a form that VRChat's video player (AVPro) can play reliably.

Features

• Use your own yt-dlp and arguments: latest yt-dlp, cookies, extra arguments
• Codec conversion: converts / merges with ffmpeg when the codec is not playable (Opus, VP9, ...) or when video and audio are separate streams (e.g. Niconico)
• GPU encoding: when video has to be re-encoded, NVIDIA / AMD / Intel GPUs are detected and used automatically (falls back to CPU on failure)
• Seeking: converted videos are served while downloading, with duration and seeking available
• IPv4 relay: the proxy connects to googlevideo over IPv4 to avoid HTTP 403 on IPv6
• Live streams: resolved on VRChat's first attempt, avoiding the error flash and extra wait
• Cache: repeated requests for the same URL (e.g. player reloads) are answered instantly
• Logs: arguments received, yt-dlp's stderr, selected formats, conversion decisions and AVPro's requests
• Test videos (opt-in): small locally generated videos with the codecs you specify

Requirements (install them yourself)

yt-dlp and ffmpeg are NOT included. Please install them yourself.

Software	Used for	Get it from
yt-dlp	resolving URLs (required)	official releases (yt-dlp_win.zip starts faster) / winget install yt-dlp.yt-dlp
ffmpeg	conversion, merging, test videos (recommended)	builds / winget install Gyan.FFmpeg

Without ffmpeg the proxy still works, but videos that need conversion (Niconico, Opus audio, ...) cannot be played.

Install

Extract the release zip and run in PowerShell:

.\install.ps1                                 # install
.\install.ps1 -YtDlpPath C:\tools\yt-dlp.exe  # specify the real yt-dlp
.\install.ps1 -Uninstall                      # remove (VRChat reinstalls its own on next start)

If script execution is blocked, use powershell -ExecutionPolicy Bypass -File .\install.ps1.

The install script:

• copies yt-dlp.exe (the proxy) into Tools and makes it read-only (so VRChat does not overwrite it on startup)
• removes only the link if the existing yt-dlp.exe is a symbolic / hard link (the link target is untouched)
• renames the old file first if it is in use
• creates vrc-video-proxy.toml and looks for the real yt-dlp (Tools\yt-dlp_win, Documents, PATH)

Note: place Tools\yt-dlp.exe as a copy, not a link.

• With a hard link, when VRChat overwrites yt-dlp.exe on startup, the original file (e.g. your build output) is overwritten too, because a hard link is the same file, not an alias.
• With a symbolic link, the proxy is still replaced by the stock yt-dlp when VRChat overwrites it (whether the link target is also overwritten depends on how VRChat writes the file).

The install script places a read-only copy, so this does not happen.

Configuration

Edit vrc-video-proxy.toml in the Tools folder (a commented template is created on first run; same as vrc-video-proxy.example.toml in the package). Main options:

Option	Default	Description
ytdlp_path		path of the real yt-dlp.exe
args_mode	append	append: VRChat's args + extra_args / replace: extra_args + URL only
extra_args	[]	extra arguments for yt-dlp (-4, -v, ...)
convert	auto	auto / always / never
allowed_video_codecs	["avc1", "h264"]	video codecs that need no conversion (prefix match)
allowed_audio_codecs	["mp4a", "aac"]	audio codecs that need no conversion (prefix match)
prefer_allowed_codecs	true	prefer formats with allowed codecs
video_encoder	auto	encoder for video conversion: auto / nvenc / amf / qsv / cpu
video_transcode_args	[]	custom ffmpeg arguments for video conversion (overrides video_encoder)
seekable_convert	true	serve converted videos while saving them, so seeking works
relay	false	relay unconverted videos too (IPv4, retry on 403)
cache_ttl_secs	300	reuse results for identical arguments for this many seconds
live_fallback	true	resolve live streams on the first attempt
prefer_audio	true	prefer formats with audio; otherwise fetch video + audio and merge
test_videos	false	enable test videos

GPU encoding

With video_encoder = "auto" (default), when video conversion is needed the proxy actually tries GPU encoders in this order and uses the first one that works:

1. NVIDIA (h264_nvenc)
2. AMD Radeon (h264_amf)
3. Intel (h264_qsv)
4. CPU (libx264) if none is available

• The result is saved in vrc-video-proxy-data\encoder.json and re-checked after 7 days or when ffmpeg changes
• If GPU encoding fails, it is retried on the CPU automatically
• Bitrate is capped per resolution (e.g. 8 Mbps for 1080p)
• Video is only re-encoded when no format with an allowed video codec exists (YouTube and Niconico normally provide H.264, so no re-encoding happens)

Test videos

With test_videos = true, these URLs return a small video with the requested codecs — useful for checking what AVPro can play.

https://vrc-video-proxy.test/hevc/opus
https://vrc-video-proxy.test/?vcodec=av1&acodec=opus&dur=30&res=1920x1080
https://www.youtube.com/watch?vrc_video_proxy_test&vcodec=vp9&raw=1

These are just examples. Change the vcodec / acodec values (or the /hevc/opus part in the path form) to any value in the table below to stream other codec combinations:

https://vrc-video-proxy.test/av1/aac          AV1 + AAC
https://vrc-video-proxy.test/vp8/vorbis       VP8 + Vorbis (webm automatically)
https://vrc-video-proxy.test/h264/none        video only (no audio)
https://vrc-video-proxy.test/none/flac        audio only

Parameter	Values
vcodec	h264 hevc av1 vp9 vp8 none (or an ffmpeg encoder name)
acodec	aac opus mp3 vorbis flac none
dur	seconds (default 10, max 600)
res / fps	default 1280x720 / 30
container	mp4 webm mkv (vp8 / vorbis default to webm)
raw	1 to return as-is, skipping the codec check and conversion

• Without raw, the video goes through the same decisions as real videos (non-allowed codecs are converted)
• VRChat may block URLs outside its trusted domains; in that case add vrc_video_proxy_test to a YouTube URL
• Generated videos are stored in vrc-video-proxy-data\test\ and reused for identical parameters

Logs

• vrc-video-proxy-logs\vrc-video-proxy_YYYYMMDD.log: main log (each line has the PID; server lines are tagged serve <pid>)
• vrc-video-proxy-logs\ffmpeg_*.log: ffmpeg's stderr
• add "-v" to extra_args for verbose yt-dlp logs

Building from source

cargo build --release      # target\release\yt-dlp.exe
.\install.ps1              # build and install (-NoBuild to skip building)
.\make-dist.ps1            # create the release package in dist\

Disclaimer

• This is an unofficial tool. It is not affiliated with VRChat, YouTube, Niconico, yt-dlp or ffmpeg.
• Use at your own risk. The author is not responsible for any damage caused by using this software.
• Respect the terms of service of each video service and copyright when fetching and playing videos.
• Check for yourself how replacing files in VRChat's Tools folder is treated under VRChat's terms of service.
• It may stop working due to changes in VRChat, yt-dlp or the video services.

License

Copyright (c) 2026 Lenqth

Licensed under either of MIT License or Apache License, Version 2.0, at your option.

Licenses of the dependencies compiled into the binary are collected in THIRD_PARTY_LICENSES.txt in the release package. yt-dlp and ffmpeg are not bundled; they are only invoked as separate processes (see their distributors for their licenses).