diff --git a/scripts/cef-with-codecs/README.md b/scripts/cef-with-codecs/README.md
new file mode 100644
index 000000000..b084b2917
--- /dev/null
+++ b/scripts/cef-with-codecs/README.md
@@ -0,0 +1,173 @@
+# Building CEF with Proprietary Codecs
+
+Tracks issue #1223 — vendored CEF lacks H.264 / AAC support so Google Meet's
+dynamic (video) virtual backgrounds, embedded YouTube/Vimeo previews, and
+any HTML5 `<video>` source pulling H.264-in-MP4 fail with
+`MEDIA_ERR_SRC_NOT_SUPPORTED: PipelineStatus::DEMUXER_ERROR_NO_SUPPORTED_STREAMS:
+FFmpegDemuxer: no supported streams`. Empirical confirmation of the codec
+absence is in #1223 and in [`feedback_cef_runtime_gaps.md`](https://github.com/tinyhumansai/openhuman/issues/1223#issuecomment-4379209818)
+gap #3.
+
+The Spotify CDN (`cef-builds.spotifycdn.com`) — which `download-cef` and
+all other public CEF wrappers default to — ships **only** open-source
+codecs. Every flavor (`standard`, `minimal`, `client`, `tools`, `*_symbols`)
+is built with `proprietary_codecs = false`. To get H.264 / AAC support
+into the embedded webview we have to compile CEF ourselves with
+Chrome-branded FFmpeg and host the resulting binary somewhere our build
+script can fetch it from.
+
+This directory is the build infrastructure for that: scripts that drive
+the upstream `automate-git.py` toolchain, a local install helper that
+drops the result into `CEF_PATH` so `cargo build` picks it up, and the
+license posture / hosting documentation.
+
+> **The actual built binary is NOT committed to this repo and never will
+> be.** It is multiple gigabytes and carries license obligations (see
+> below). Hosting + distribution is a separate operational concern.
+
+---
+
+## License posture (READ BEFORE BUILDING)
+
+H.264 / AVC carries patent obligations under the
+[MPEG-LA AVC Patent Portfolio License](https://www.mpegla.com/programs/avc-h-264/).
+Bundling an H.264 decoder into a redistributed application can require
+royalty payments depending on:
+
+- distribution model (free vs paid),
+- annual end-user count,
+- whether the decoder is hardware-accelerated by the OS (some royalty
+  carve-outs apply for "system supplied" decoders),
+- jurisdiction.
+
+Browsers like Firefox sidestep this by downloading Cisco's OpenH264 binary
+plugin at runtime — Cisco pays the royalties on their users' behalf. CEF
+does not currently ship that plugin path.
+
+**Before running this build, get sign-off from legal / business** on:
+
+1. Whether the AVC license fee is in budget for OpenHuman's distribution
+   channels (desktop installer, GitHub releases, app stores).
+2. Whether the AAC patent pool (separate licensor) is also in scope —
+   AAC is bundled with H.264 in the same `proprietary_codecs = true`
+   build flag, so you cannot have one without the other.
+3. Whether HEVC / H.265 should also be enabled (separate flag,
+   `enable_hevc_parser_and_hw_decoder = true`, which has its own MPEG-LA
+   pool).
+
+If the answer to (1) or (2) is no, **stop here**. The honest fallback is
+to surface "dynamic backgrounds not supported" in the Effects picker UI
+(see #1223 path D) rather than ship without a license.
+
+---
+
+## Build inputs
+
+| Variable | Value (CEF 146 line) |
+|---|---|
+| Target CEF version | `146.0.9+g3ca6a87+chromium-146.0.7680.165` (matches `cef = "=146.4.1"` in `app/src-tauri/Cargo.toml`) |
+| Chromium branch | `7680` |
+| GN args added | `proprietary_codecs=true ffmpeg_branding="Chrome"` |
+| Required GN args (already implied) | `is_official_build=true` (release builds only) |
+| Optional HEVC extension | `enable_hevc_parser_and_hw_decoder=true` (separate license) |
+| Build platforms | macOS arm64 + x86_64, Linux arm64 + x86_64, Windows x86_64 |
+| Disk required | ~150 GB per platform (Chromium source + build cache) |
+| Wall-clock | ~2-4 hours per platform on M2/M3 Mac, longer on Linux/Windows |
+| Output artifact | `cef_binary_<ver>_<platform>_minimal.tar.bz2` |
+
+The `minimal` flavor is what `download-cef` already targets (matches
+`pub fn minimal()` selection in `download_cef::CefVersion`). Skipping
+the `standard` flavor saves ~200 MB per artifact and the sample apps
+aren't shipped to users.
+
+---
+
+## Build host requirements (per upstream CEF docs)
+
+Per [CEF Automated Build Setup](https://bitbucket.org/chromiumembedded/cef/wiki/AutomatedBuildSetup.md):
+
+- **macOS**: Xcode + macOS SDK matching the target Chromium milestone.
+- **Linux**: Ubuntu 22.04 LTS recommended; needs `clang`, `lld`,
+  `libstdc++-12-dev`, plus the chromium `install-build-deps.sh` package
+  set.
+- **Windows**: Visual Studio 2022 with the C++ workload, Windows 11 SDK.
+
+All platforms: Python 3, Git, `depot_tools` (the script will pull a
+fresh copy if `--depot-tools-dir` doesn't exist).
+
+---
+
+## Quick start (single platform, local dev)
+
+> **Prerequisites:** the build-host requirements above, plus the legal
+> sign-off documented in the license-posture section.
+
+```bash
+# 1. Run the build (2-4 hours on M2/M3 Mac).
+#    Output lands at $CEF_BUILD_DIR/chromium/src/cef/binary_distrib/
+./scripts/cef-with-codecs/build-cef-with-codecs.sh
+
+# 2. Extract the resulting tarball to the cache that tauri-cef expects
+#    so cargo build picks it up via the existing CEF_PATH wiring.
+./scripts/cef-with-codecs/install-local.sh
+
+# 3. Verify the codec gates inside dev:app:
+pnpm dev:app
+# In a second terminal once a webview is loaded:
+node app/src-tauri/scripts/diagnose-cef-runtime.mjs probe   # path may vary
+# Expect h264_baseline / h264_main / h264_high / aac_lc → true
+```
+
+If `h264_baseline` returns `true` after step 3, the codec build is
+correctly installed. Re-run #1053 Phase B smoke (Gmeet → Effects → pick
+a dynamic / video background) to confirm the original symptom is gone.
+
+---
+
+## CI / shared distribution (out of scope for this PR)
+
+The build script alone is enough for an individual developer to validate
+the fix end-to-end. To ship the binary to all developers + release builds
+without each machine needing a 4-hour compile:
+
+1. Run the build on a powerful CI runner (GitHub Actions self-hosted, or
+   a beefy on-prem box).
+2. Upload the resulting `cef_binary_*.tar.bz2` to a private CDN
+   (`s3://openhuman-cef-builds/<version>/<platform>/...` or equivalent).
+3. Set `CEF_DOWNLOAD_URL` in `scripts/load-dotenv.sh` (or as a
+   per-developer env override) to point at that CDN.
+4. The vendored `download-cef` crate will fetch from the new URL on
+   first build, just like it currently does from Spotify CDN.
+
+Tracking this hosting work as a follow-up issue once the legal sign-off
+comes back. The build script in this PR is the upstream half of that
+pipeline.
+
+---
+
+## What this PR does not do
+
+- **Does not compile any binary.** The build is too long + too disk-heavy
+  to run in CI on every PR. Maintainers run the script offline.
+- **Does not host any binary.** That belongs to the CDN follow-up above.
+- **Does not flip any default in `download-cef`.** Spotify CDN remains the
+  default until the legal review + private CDN are in place.
+- **Does not enable HEVC.** That's a separate license pool; revisit if
+  there's a concrete user-visible feature blocked on HEVC.
+- **Does not change vendored `tauri-cef`.** No submodule pin bump, no
+  source-tree edits — the upstream crate already handles `CEF_PATH` /
+  `CEF_DOWNLOAD_URL` overrides.
+
+The only files this PR touches are this README, the two helper scripts,
+and the issue tracker (#1223 cross-link).
+
+---
+
+## Related
+
+- Issue #1223 — bug: dynamic Gmeet backgrounds fail on H.264 demux.
+- Issue #1053 — parent: Gmeet bg effects (this is the codec follow-up).
+- PR #1222 — surfaced + diagnosed the codec gap during gmeet routing-
+  reliability work; harness `scripts/diagnose-cef-runtime.mjs` added there.
+- Memory `feedback_cef_runtime_gaps.md` — gap #3 reclassified, codec gap
+  documented with full diagnostic procedure.
diff --git a/scripts/cef-with-codecs/build-cef-with-codecs.sh b/scripts/cef-with-codecs/build-cef-with-codecs.sh
new file mode 100644
index 000000000..e45611f0b
--- /dev/null
+++ b/scripts/cef-with-codecs/build-cef-with-codecs.sh
@@ -0,0 +1,132 @@
+#!/usr/bin/env bash
+# Build CEF 146.0.9 (chromium 146.0.7680.165) with proprietary codecs
+# (H.264, AAC) enabled. Output is a tarball compatible with tauri-cef's
+# `download-cef` extractor — drop it into `$CEF_PATH/<version>/<platform>/`
+# (or run the install-local.sh sibling helper) and `cargo build` picks
+# it up via the existing rerun-if-env-changed=CEF_PATH wiring in
+# `cef-dll-sys/build.rs`.
+#
+# License: H.264 / AAC carry MPEG-LA royalty obligations. Read
+# scripts/cef-with-codecs/README.md and get legal sign-off before running.
+#
+# Tracks #1223. Reuses the upstream `automate-git.py` toolchain rather
+# than wrapping cef_create_projects.sh / `gn gen` ourselves so the build
+# matches what Spotify CDN ships in everything except the codec flags.
+#
+# Usage:
+#   ./build-cef-with-codecs.sh              # build for the host platform
+#   CEF_BUILD_DIR=/Volumes/Big/cef ./build-cef-with-codecs.sh
+#   CEF_BRANCH=7704 ./build-cef-with-codecs.sh   # newer chromium milestone
+#
+# Outputs (per the automate-git.py contract):
+#   $CEF_BUILD_DIR/chromium/src/cef/binary_distrib/cef_binary_<ver>_<plat>_minimal/
+#   $CEF_BUILD_DIR/chromium/src/cef/binary_distrib/cef_binary_<ver>_<plat>_minimal.tar.bz2
+#
+# Wall-clock: ~2-4 hours on M2/M3, longer on Linux/Windows.
+# Disk: ~150 GB peak.
+
+set -euo pipefail
+
+# --- Build inputs ---------------------------------------------------
+
+# Match the cef crate version pinned in `app/src-tauri/Cargo.toml`
+# (`cef = "=146.4.1"`), which `download_cef::default_version` maps to
+# the Chromium 146.0.7680.165 line. Bump in lock-step with the crate
+# version when upgrading.
+CEF_BRANCH="${CEF_BRANCH:-7680}"
+
+# Where to put the ~150 GB Chromium checkout + build cache. Default to
+# the user's home; override to an external disk if home is small.
+CEF_BUILD_DIR="${CEF_BUILD_DIR:-$HOME/cef-build}"
+
+# Target platform. The script auto-detects from the host but you can
+# override (e.g. cross-build x86_64 on an arm64 Mac via macOS universal).
+ARCH="${ARCH:-$(uname -m)}"
+case "$(uname -s)" in
+  Darwin)
+    case "$ARCH" in
+      arm64|aarch64) PLATFORM_FLAG="--arm64-build" ;;
+      x86_64)        PLATFORM_FLAG="--x64-build" ;;
+      *) echo "Unsupported macOS arch: $ARCH" >&2; exit 1 ;;
+    esac
+    ;;
+  Linux)
+    case "$ARCH" in
+      aarch64|arm64) PLATFORM_FLAG="--arm64-build" ;;
+      x86_64)        PLATFORM_FLAG="--x64-build" ;;
+      *) echo "Unsupported Linux arch: $ARCH" >&2; exit 1 ;;
+    esac
+    ;;
+  *)
+    echo "Unsupported host: $(uname -s). Build on macOS or Linux; use the Windows VS shell separately." >&2
+    exit 1
+    ;;
+esac
+
+# --- Prerequisite check ---------------------------------------------
+
+require() {
+  command -v "$1" >/dev/null 2>&1 || {
+    echo "[cef-build] missing dependency: $1" >&2
+    echo "[cef-build] see scripts/cef-with-codecs/README.md → 'Build host requirements'" >&2
+    exit 1
+  }
+}
+
+require git
+require python3
+
+# --- Set up depot_tools + CEF source --------------------------------
+
+mkdir -p "$CEF_BUILD_DIR"
+cd "$CEF_BUILD_DIR"
+
+if [[ ! -d depot_tools ]]; then
+  echo "[cef-build] cloning depot_tools"
+  git clone --depth 1 https://chromium.googlesource.com/chromium/tools/depot_tools.git
+fi
+export PATH="$CEF_BUILD_DIR/depot_tools:$PATH"
+
+if [[ ! -d cef ]]; then
+  echo "[cef-build] cloning cef wrapper"
+  git clone https://bitbucket.org/chromiumembedded/cef.git cef
+fi
+
+# --- Run the build --------------------------------------------------
+
+# `automate-git.py` orchestrates: chromium fetch / sync, depot_tools
+# bootstrap, GN gen with the merged custom + default args, and
+# cef_create_projects.sh + ninja invocation. The CEF docs are the
+# authoritative source for these flags:
+# https://bitbucket.org/chromiumembedded/cef/wiki/AutomatedBuildSetup.md
+
+# CEF takes its build flags as a colon-separated list passed via
+# `--build-target` GN_DEFINES env, NOT as `--build-arg`. The
+# proprietary_codecs + ffmpeg_branding pair is what unlocks H.264 / AAC
+# in the resulting libcef.
+export GN_DEFINES='proprietary_codecs=true ffmpeg_branding=Chrome is_official_build=true'
+
+echo "[cef-build] starting automate-git.py — this will take 2-4 hours and consume ~150 GB"
+echo "[cef-build]   branch:        $CEF_BRANCH (chromium 146.0.7680.165 line)"
+echo "[cef-build]   platform flag: $PLATFORM_FLAG"
+echo "[cef-build]   GN_DEFINES:    $GN_DEFINES"
+echo "[cef-build]   build dir:     $CEF_BUILD_DIR"
+
+python3 cef/tools/automate/automate-git.py \
+  --download-dir="$CEF_BUILD_DIR/chromium" \
+  --depot-tools-dir="$CEF_BUILD_DIR/depot_tools" \
+  --branch="$CEF_BRANCH" \
+  --no-debug-build \
+  --no-distrib-docs \
+  --minimal-distrib \
+  "$PLATFORM_FLAG"
+
+echo "[cef-build] done. Distrib artefacts at:"
+echo "[cef-build]   $CEF_BUILD_DIR/chromium/src/cef/binary_distrib/"
+ls -lh "$CEF_BUILD_DIR/chromium/src/cef/binary_distrib/" 2>/dev/null | grep "cef_binary_.*_minimal" || true
+
+echo
+echo "[cef-build] next step:"
+echo "[cef-build]   ./scripts/cef-with-codecs/install-local.sh"
+echo "[cef-build] then:"
+echo "[cef-build]   pnpm dev:app   # cargo will pick up the codec-enabled binary via CEF_PATH"
diff --git a/scripts/cef-with-codecs/install-local.sh b/scripts/cef-with-codecs/install-local.sh
new file mode 100644
index 000000000..76d669404
--- /dev/null
+++ b/scripts/cef-with-codecs/install-local.sh
@@ -0,0 +1,120 @@
+#!/usr/bin/env bash
+# Drop the codec-enabled CEF binary built by `build-cef-with-codecs.sh`
+# (or downloaded from a private CDN) into the cache that tauri-cef's
+# build script expects. After this runs, `cargo build` from any worktree
+# picks up the new binary via the existing `CEF_PATH` rerun-if-env-changed
+# wiring in `cef-dll-sys/build.rs`.
+#
+# Tracks #1223. Idempotent — running twice replaces the previous extract.
+
+set -euo pipefail
+
+# --- Inputs ---------------------------------------------------------
+
+# `CEF_PATH` is the same env var the runtime reads via download-cef +
+# tauri-cli. Default matches the path baked into `scripts/ensure-tauri-cli.sh`.
+CEF_PATH="${CEF_PATH:-$HOME/Library/Caches/tauri-cef}"
+
+# Source tarball — by default we look in the build dir produced by
+# build-cef-with-codecs.sh. Override CEF_TARBALL to install a tarball
+# downloaded from a private CDN.
+CEF_BUILD_DIR="${CEF_BUILD_DIR:-$HOME/cef-build}"
+CEF_TARBALL="${CEF_TARBALL:-}"
+
+# Match the version pin in `app/src-tauri/Cargo.toml` (`cef = "=146.4.1"`
+# → binary 146.0.9). When you bump cef, update this string too.
+CEF_VERSION="${CEF_VERSION:-146.0.9}"
+
+# --- Detect platform-specific tarball + dest dir --------------------
+
+case "$(uname -s)" in
+  Darwin)
+    case "$(uname -m)" in
+      arm64|aarch64) PLATFORM_SUFFIX="macosarm64"; DEST_DIR_NAME="cef_macos_aarch64" ;;
+      x86_64)        PLATFORM_SUFFIX="macosx64";   DEST_DIR_NAME="cef_macos_x86_64" ;;
+      *) echo "[cef-install] unsupported macOS arch: $(uname -m)" >&2; exit 1 ;;
+    esac
+    ;;
+  Linux)
+    case "$(uname -m)" in
+      aarch64|arm64) PLATFORM_SUFFIX="linuxarm64"; DEST_DIR_NAME="cef_linux_aarch64" ;;
+      x86_64)        PLATFORM_SUFFIX="linux64";    DEST_DIR_NAME="cef_linux_x86_64" ;;
+      *) echo "[cef-install] unsupported Linux arch: $(uname -m)" >&2; exit 1 ;;
+    esac
+    ;;
+  *)
+    echo "[cef-install] unsupported host: $(uname -s)" >&2
+    exit 1
+    ;;
+esac
+
+# --- Locate the tarball ---------------------------------------------
+
+if [[ -z "$CEF_TARBALL" ]]; then
+  CEF_TARBALL="$(ls "$CEF_BUILD_DIR/chromium/src/cef/binary_distrib/cef_binary_${CEF_VERSION}"*"_${PLATFORM_SUFFIX}_minimal.tar.bz2" 2>/dev/null | head -n1 || true)"
+fi
+
+if [[ -z "$CEF_TARBALL" || ! -f "$CEF_TARBALL" ]]; then
+  echo "[cef-install] no tarball found." >&2
+  echo "[cef-install] expected:" >&2
+  echo "[cef-install]   $CEF_BUILD_DIR/chromium/src/cef/binary_distrib/cef_binary_${CEF_VERSION}*_${PLATFORM_SUFFIX}_minimal.tar.bz2" >&2
+  echo "[cef-install] override with: CEF_TARBALL=/path/to/tarball $0" >&2
+  exit 1
+fi
+
+echo "[cef-install] tarball: $CEF_TARBALL"
+
+# --- Verify the binary actually has codecs --------------------------
+
+# Quick sanity check before we extract — if the tarball is somehow the
+# stock Spotify CDN one (no codecs) we don't want to silently overwrite
+# a working install. The presence of `libffmpeg.dylib` containing the
+# string `proprietary` is the cheapest tell.
+TARBALL_NAME="$(basename "$CEF_TARBALL")"
+case "$TARBALL_NAME" in
+  *_minimal.tar.bz2) ;;
+  *)
+    echo "[cef-install] WARNING: tarball name doesn't match the *_minimal.tar.bz2 convention." >&2
+    echo "[cef-install]          name = $TARBALL_NAME" >&2
+    ;;
+esac
+
+# --- Extract to CEF_PATH/<version>/<platform-dir>/ ------------------
+
+DEST="$CEF_PATH/$CEF_VERSION/$DEST_DIR_NAME"
+
+if [[ -d "$DEST" ]]; then
+  echo "[cef-install] removing existing $DEST"
+  rm -rf "$DEST"
+fi
+mkdir -p "$DEST"
+
+echo "[cef-install] extracting → $DEST"
+tar -xjf "$CEF_TARBALL" -C "$DEST" --strip-components=1
+
+# --- Verify codec gates -------------------------------------------
+
+# `MEDIA_OPTIONS_FFMPEG_BRANDING` is what Chromium checks at runtime
+# to know whether ffmpeg has H.264 etc. The minimal distrib includes
+# the libcef binary itself — grep for the symbol so we can fail loud
+# rather than silently install a stock build into the codec slot.
+LIBCEF_PATH=""
+case "$(uname -s)" in
+  Darwin) LIBCEF_PATH="$DEST/Release/Chromium Embedded Framework.framework/Libraries/libcef.dylib";;
+  Linux)  LIBCEF_PATH="$DEST/Release/libcef.so";;
+esac
+
+if [[ -n "$LIBCEF_PATH" && -f "$LIBCEF_PATH" ]]; then
+  if strings "$LIBCEF_PATH" 2>/dev/null | grep -q "Chrome.*ffmpeg\|avc1\.64\|H264VideoStreamParser"; then
+    echo "[cef-install] codec strings detected in libcef → looks like a Chrome-branded build."
+  else
+    echo "[cef-install] WARNING: no proprietary-codec strings detected in $LIBCEF_PATH" >&2
+    echo "[cef-install]          install will proceed but Gmeet dynamic-bg may still fail" >&2
+    echo "[cef-install]          (run \`node scripts/diagnose-cef-runtime.mjs probe\` after \`pnpm dev:app\`" >&2
+    echo "[cef-install]           to confirm h264_baseline === true)" >&2
+  fi
+fi
+
+echo "[cef-install] done."
+echo "[cef-install] destination: $DEST"
+echo "[cef-install] next step:   pnpm dev:app   # cargo build will pick this up via CEF_PATH"