davinci-resolve-linux-aac-fix

Native AAC-in-MP4 decode for DaVinci Resolve on Linux, delivered as a single LD_PRELOAD interoperability shim. The shim looks at each file Resolve opens, dispatches per file: LC AAC + 4-byte-length esds → in-binary native decode path (no sibling); compact-length esds or non-LC audioObjectType → ffmpeg AAC→FLAC sibling in a cache directory that Resolve can already decode. No on-disk modification of /opt/resolve/bin/resolve. No FLAC siblings cluttering your source directories.

Interoperability statement. This project is an independently authored compatibility layer that interposes standard POSIX/libc symbols to enable a lawfully licensed installation of DaVinci Resolve on Linux to interoperate with AAC-in-MP4 media files the user lawfully possesses. It does not circumvent any technological protection measure, contains no code or binary fragments extracted from DaVinci Resolve, distributes no BlackmagicDesign binaries, and modifies nothing on disk. It is published under 17 U.S.C. §1201(f) and the Apache License 2.0.

DaVinci Resolve and BlackmagicDesign are trademarks of Blackmagic Design Pty. Ltd. This project is not affiliated with, endorsed by, or sponsored by Blackmagic Design.

Quick install

curl -fsSL https://davinci-resolve-linux-aac-fix.netlify.app/install.sh | bash

Prefer to read the script first?

curl -fsSL https://davinci-resolve-linux-aac-fix.netlify.app/install.sh -o install.sh
less install.sh   # review it
bash install.sh

If the raw.githubusercontent.com CDN is being slow for you (occasionally happens for a few minutes after a GitHub repo rename), use the git-clone install path — same result, immune to raw-CDN delays:

git clone --depth 1 https://davinci-resolve-linux-aac-fix.netlify.app/repo.git /tmp/davinci-resolve-linux-aac-fix && bash /tmp/davinci-resolve-linux-aac-fix/install.sh

The installer is fully scoped to your user account (~/.local/lib, ~/.local/bin, ~/.local/share/applications) — no root needed, your /opt/resolve binary is never modified. After it finishes you'll see a new app-menu entry: DaVinci Resolve (Native AAC) alongside the regular one. Click it instead of the default; everything else works the same.

To uninstall:

curl -fsSL https://davinci-resolve-linux-aac-fix.netlify.app/uninstall.sh | bash

TL;DR

Background

Resolve on Linux does not include an AAC decoder, by BlackmagicDesign's own explanation: licensing. From the official BMD forum thread:

"the simple answer is due to licensing" — Peter Chamberlain, BMD

Every Linux Resolve user importing camera footage (Canon, GoPro, smartphones, screen-capture) hits silent audio on first import. Eight years of forum threads, an ArchWiki section, editorial coverage, and ~98 ⭐ on a community AAC encoder plugin all confirm the pain. The standard community workaround pre-transcodes the audio to a FLAC sibling for every imported file and tells Resolve to read that — functional, but slow on first import and clutters every project directory.

This shim takes a different path: it patches the Resolve binary in memory at process startup so the codec dispatch reaches Resolve's own dormant native AAC builder, supplied with the right MPEG-4 AudioSpecificConfig. For LC AAC with 4-byte-length esds boxes — what ffmpeg, x264, Apple, GoPro, Canon, and basically every consumer encoder emits — that's all it takes: native decode on import, instant waveform, no sibling files. For the rare edge-case AAC variants the cave can't decode safely (compact-length esds or true HE-AAC SBR audioObjectType≠2), the shim notices at open() time and falls through to a one-shot ffmpeg AAC→FLAC transcode in a cache directory — same effect as the community workaround, but centralized in the cache, not littered next to your source files.

How it works

The hybrid shim does two independent things in one LD_PRELOAD:

1. In-memory cave patches (cave path — for LC AAC, 4-byte-length esds). DaVinci Resolve on Linux ships with a working libavcodec.so.60 and an audio-codec dispatcher that routes FOURCC tokens (mp3, flac, opus, …) to libavcodec. It also ships a dormant native-AAC code path (builder + decode entry) — but the FOURCC switch has no aac arm to reach it, and the binary's esds-to-extradata copy hands libavcodec the wrong descriptor bytes (the 42-byte ES_Descriptor instead of the 5-byte AudioSpecificConfig at offset +0x1f), causing libavcodec to return -38 / "Audio object type 0 not implemented". The shim does seven small in-memory byte changes at process startup that together: (a) add the missing aac arm to the FOURCC switch, (b) route it past the disabled wrapper, (c) supply the correct AudioSpecificConfig pointer (+0x1f past the esds header) via a short trampoline in an existing zero-byte region of a readable LOAD segment that the shim makes executable with mprotect().

Net effect for LC AAC files: Resolve's own existing libavcodec call site decodes AAC packets the same way it decodes FLAC, MP3, and Opus. Peak generation + playback both go through the native path. No second decoder is shipped or linked.

2. Per-file dispatch at open() time (sibling path — for edge-case AAC). The shim also hooks 17 path-taking syscalls (open/openat/open64/ fopen/fopen64, the stat-family, access). For each .mp4/.m4a/.mov path Resolve touches, the shim parses the file's MPEG-4 esds box once and decides:

• LC AAC + 4-byte-length esds → leave alone; the cave decodes it.
• Compact-length esds (1-byte MPEG-4 descriptor lengths) OR audioObjectType != 2 → invoke ~/.local/bin/resolve-codec-patch fix-file <source>, which runs ffmpeg AAC→FLAC into a cache sibling in ${XDG_CACHE_HOME:-$HOME/.cache}/resolve-aac/, then transparently redirects Resolve's open() of the source to the cache sibling (FLAC-in-mp4, which Resolve decodes natively).
• No esds box at all (FLAC, MP3, raw audio, no audio) → no-op, Resolve handles natively.

The decision is cached per-process so each path is probed exactly once, even if Resolve open()s it many times across probe / preview / peak-gen / render.

Safety properties of both paths:

• Runs as a __attribute__((constructor)) at ld.so load time.
• Verifies it's loaded into /opt/resolve/bin/resolve and no other process (helper subprocesses like fuscript are NOT patched).
• Verifies seven small byte-signatures match the supported Resolve version before writing any cave patches (mismatch → no-op, logs skip, Resolve runs as if the shim weren't loaded).
• Uses mprotect() to make the necessary pages writable, applies the patch bytes, then restores PROT_READ|PROT_EXEC.
• Touches zero files on disk in the cave path; the only effect is in this process's private COW pages, which vanish when Resolve exits.
• The sibling path writes only into ${XDG_CACHE_HOME:-$HOME/.cache}/resolve-aac/; never next to your source files.

Supported Resolve version

What's verified end-to-end

Across these representative AAC variants (8 files, real-world muxers): LC AAC mono 44.1k, LC AAC stereo 48k, LC AAC dynamic-envelope 44.1k mono, LC AAC dynamic music-like, an HE-AAC-labeled file whose ASC is actually LC (audioObjectType=2), a compact-length-esds AAC (1-byte descriptor lengths), an AAC with illegal CCE elements in the bitstream, plus a control FLAC file. Every file: PFL peak-file populated and varying; Resolve survives every import; host binary md5 unchanged across all test cycles; no FLAC sibling created next to any source file.

Update safety

The shim verifies the bytes at each cave patch site against a known-version fingerprint before writing. On a Resolve update (different binary, different offsets), all fingerprints mismatch, the constructor logs SKIP orig-mismatch for each site, and exits without writing cave patches. The sibling path remains usable on any Resolve version (it doesn't depend on binary offsets), so even on an unsupported Resolve build, the shim gracefully degrades to "every AAC file gets transcoded once into the cache dir" — same effect as the original community workaround, but centralized.

To restore native cave decode after a Resolve update, the patch sites need to be re-derived for the new binary. See docs/REVERSE-ENGINEERING-NOTES.md.

Build

gcc -shared -fPIC -O2 -Wall -o aac_hybrid_shim.so src/aac_hybrid_shim.c
install -Dm755 aac_hybrid_shim.so ~/.local/lib/aac_hybrid_shim.so

That's it — no dependencies beyond libc (mprotect, readlink, pthread). No bundled AAC decoder. The shim calls Resolve's own bundled libavcodec.so.60 via Resolve's own existing call sites for the cave path, and spawns ffmpeg via tools/resolve-codec-patch for the sibling path. Nothing about AAC patent licensing changes vs. what BMD and your distro already ship.

The one-line installer at the top of this README does this for you plus the wrapper launcher and app-menu entry.

Use

Add the shim to your Resolve launcher's LD_PRELOAD and point it at a cache directory. A complete example launcher is in example/resolve-launcher.sh. Minimal form:

#!/bin/bash
export LD_PRELOAD="$HOME/.local/lib/aac_hybrid_shim.so${LD_PRELOAD:+:$LD_PRELOAD}"
export AAC_REDIRECT_CACHE_DIR="${XDG_CACHE_HOME:-$HOME/.cache}/resolve-aac"
exec /opt/resolve/bin/resolve "$@"

AAC_REDIRECT_CACHE_DIR defaults sensibly even if unset — it's there so you can put the cache on a fast disk if you want.

Optional: set AAC_HYBRID_LOG=/tmp/aac-hybrid.log (or any path you can write to) to see the shim's per-file decisions and ffmpeg invocations, which is useful when porting to a new Resolve version.

Project files

• src/aac_hybrid_shim.c — the shim source (~1100 lines, no external deps).
• tools/resolve-codec-patch — pure-ffmpeg AAC→FLAC sibling helper invoked by the shim's sibling path. Independently usable from a shell if you want.
• example/resolve-launcher.sh — example Resolve launcher with the shim wired in.
• docs/REVERSE-ENGINEERING-NOTES.md — how the cave patch sites were derived; useful when porting to a new Resolve version.
• BUILD.md — build, install, smoke-test, and uninstall steps.
• CHANGELOG.md — version history (v0.1 = native-only, v0.2 = hybrid).

What this project is — and isn't

• Is: an independently authored compatibility shim that lets Resolve's own bundled libavcodec decode AAC, by adding the missing FOURCC arm and fixing the esds → AudioSpecificConfig pointer; plus a small per-file dispatcher that hands the rare edge-case AAC variants to ffmpeg via a centralized cache rather than littering project directories with *.resolve.mp4 siblings.
• Isn't: a Resolve crack, a license bypass, a DRM circumvention tool, or a redistribution of any BlackmagicDesign binary. It contains no code, binaries, byte fragments, headers, symbols, or RTTI strings extracted from /opt/resolve/bin/resolve — only a small set of patch-site fingerprint bytes (used to verify "this is the supported Resolve version" before patching) and the small set of replacement bytes that encode the actual patch instructions. You must already own a lawful copy of DaVinci Resolve to use this shim; nothing here helps you obtain one.

The shim is what wine, dxvk, vkd3d, youtube-dl, and similar interoperability projects are: standard POSIX function-interposition (LD_PRELOAD) used to enable two independently authored programs (Resolve and libavcodec) to talk through a missing arm in one of them.

Patent / licensing note (read this)

AAC is patent-encumbered. Most Linux distributions ship a libavcodec package whose AAC support is licensed (or whose licensing position is documented by the distribution). This shim does not ship an AAC decoder. It calls into the libavcodec.so.60 that BlackmagicDesign already ships with Resolve via Resolve's own existing call sites for the cave path, and via the system ffmpeg (which you installed and which decodes AAC under its own licensing terms) for the sibling path. Whatever the AAC patent-licensing position is for those two binaries on your system, it doesn't change here. If your jurisdiction or workflow imposes additional AAC patent obligations on you, that's separately your responsibility.

License

Apache License 2.0 — see LICENSE. The Apache 2.0 patent grant applies to contributions by the authors of this shim; it does not (and cannot) grant AAC patents held by third parties.

Contributing

Issues and PRs welcome. The two most-wanted contributions:

1. Re-derivation of the cave patch sites for newer Resolve versions when BMD releases one (the sibling path doesn't need re-deriving; only the cave path does — and the shim already degrades to "always sibling" on unsupported binaries, so the project remains useful even before someone ports the cave).
2. Coverage of additional AAC encoder variants the sibling path's box parser hasn't seen yet (open an issue with a short test file).

Please do not file issues with "crack", "bypass", "unlock", "activation", or "license" framing. Issues that aren't strictly about codec interoperability will be closed.

Version history

• v0.2 — hybrid shim (current). Single LD_PRELOAD, per-file dispatch via MPEG-4 box parsing at open() time. LC AAC → cave (native); edge cases → ffmpeg sibling in cache directory.
• v0.1 — native-only cave shim. Handled LC AAC + 4-byte-length esds correctly but crashed Resolve on the compact-length-esds and HE-AAC SBR edge cases; users had to keep the community ffmpeg-FLAC workaround as a fallback. Source preserved at git tag v0.1 for historical reference. New installations should use v0.2.