The latest articles on DEV Community by Saken Tukenov (@stukenov). https://dev.to/stukenov https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F3947692%2Fad0d18a8-9403-4ac7-8973-e6f5800df5a8.jpeg https://dev.to/stukenov en Saken Tukenov Sat, 23 May 2026 13:01:25 +0000 https://dev.to/stukenov/rav2d-we-ported-an-av2-video-decoder-from-c-to-rust-heres-why-2n7a https://dev.to/stukenov/rav2d-we-ported-an-av2-video-decoder-from-c-to-rust-heres-why-2n7a <p>Video decoders parse untrusted bitstreams from the internet — they are a prime target for memory corruption exploits. Historical CVEs in video decoders (libvpx, dav1d, ffmpeg) are overwhelmingly buffer overflows, use-after-free, and integer overflows in C parsing code.</p> <p>We completed <strong>rav2d</strong> — a full Rust port of <a href="https://code.videolan.org/videolan/dav2d" rel="noopener noreferrer">dav2d</a>, the AV2 video decoder.</p> <h2> By the numbers </h2> <ul> <li> <strong>47,000+ lines</strong> of Rust across 47 source files</li> <li> <strong>786 unit tests</strong> passing</li> <li> <strong>100%</strong> of C decoder logic ported</li> <li>Assembly DSP kernels shared via FFI (not rewritten)</li> </ul> <h2> What's ported </h2> <p>The entire decode pipeline: OBU parsing, MSAC entropy decoding, block decode (intra/inter/compound), deblocking filter, CDEF, loop restoration (NS/PC Wiener, GDF), film grain synthesis, motion compensation, inverse transforms, reference management, and thread task scheduling.</p> <h2> Why Rust? </h2> <div class="table-wrapper-paragraph"><table> <thead> <tr> <th>Component</th> <th>dav2d (C)</th> <th>rav2d (Rust)</th> </tr> </thead> <tbody> <tr> <td>Bitstream parsing</td> <td>C (unsafe)</td> <td>Rust (bounds-checked)</td> </tr> <tr> <td>Decode orchestration</td> <td>C (unsafe)</td> <td>Rust (safe, typed)</td> </tr> <tr> <td>Filter pipeline</td> <td>C (unsafe)</td> <td>Rust (bounds-checked)</td> </tr> <tr> <td>DSP kernels</td> <td>Assembly</td> <td>Assembly (shared via FFI)</td> </tr> <tr> <td>Type safety</td> <td>Weak (enums as ints)</td> <td>Strong (enum variants, pattern matching)</td> </tr> </tbody> </table></div> <h2> Approach </h2> <p>Following the proven <a href="https://github.com/memorysafety/rav1d" rel="noopener noreferrer">rav1d</a> strategy (AV1 Rust port, funded by Prossimo/ISRG):</p> <ol> <li>FFI bindings to dav2d's hand-optimized assembly</li> <li>Progressive C-to-Rust port of the core decoder</li> <li>Conformance testing at every step</li> </ol> <p><strong>Repo:</strong> <a href="https://github.com/stukenov/rav2d" rel="noopener noreferrer">github.com/stukenov/rav2d</a></p> <p>BSD 2-Clause license.</p> rust video security opensource