--- title: Show HN: SIMD Viterbi Decoder in Rust | daily.dev description: A new Rust crate called `fec` implements forward error correction algorithms for SDR, space, and satellite applications. It provides convolutional codes with a... canonical: https://daily.dev/posts/show-hn-simd-viterbi-decoder-in-rust-bi668xjso twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Show HN: SIMD Viterbi Decoder in Rust | daily.dev og:description: A new Rust crate called `fec` implements forward error correction algorithms for SDR, space, and satellite applications. It provides convolutional codes with a... og:url: https://daily.dev/posts/show-hn-simd-viterbi-decoder-in-rust-bi668xjso og:image: https://api.daily.dev/og/posts/Bi668xjso.png og:image:alt: Show HN: SIMD Viterbi Decoder in Rust og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Show HN: SIMD Viterbi Decoder in Rust **[Hacker News](https://daily.dev/sources/hn)** · 4 min read · 0 upvotes · 0 comments ## Summary A new Rust crate called `fec` implements forward error correction algorithms for SDR, space, and satellite applications. It provides convolutional codes with a Viterbi decoder (hard and soft decision) supporting rates from 1/2 to 1/8 and orders k=4 to k=16, plus Reed–Solomon codes over GF(2⁸) including the standard CCSDS (255,223) code. With the SIMD feature enabled on nightly Rust (SSE/AVX2/AVX512), it outperforms the reference C library libfec across all benchmarked codes — up to 3x faster for convolutional codes and ~4.5x faster for Reed-Solomon. The crate is bit-compatible with libfec and includes a companion shim crate exposing the same C ABI for drop-in use in existing C codebases. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Community take How the wider developer community reacted, aggregated from 1 discussion and 9 comments across hackernews (as of 2026-08-05). **TL;DR:** The community is generally positive and curious about this Rust FEC crate, with questions about real-world applicability (e.g., GOES satellite decoding) and implementation details like Reed-Solomon multiplication strategies. The author is actively engaged answering questions. **Sentiment:** 70% positive · 20% mixed · 10% skeptical **The case for** - The crate matches or beats libfec's hand-written SSE2 assembly for convolutional codes using a generic templated decoder, which commenters found impressive. - The C ABI shim makes it a practical drop-in for existing C codebases like goestools without a full rewrite. - The Viterbi algorithm's versatility across domains (signal processing, NLP) was noted with appreciation. **The pushback** - Integrating the crate into existing C projects like goestools still requires adding a Rust dependency, which may be a barrier. - A question was raised about whether log-based multiplication in Reed-Solomon is actually faster than a 64KB direct-lookup table on modern processors, suggesting a potential optimization gap. **By community** - hackernews (positive): Commenters are enthusiastic and curious, asking practical questions about satellite decoding use cases and implementation choices, with the author actively clarifying performance results and methodology. **Hottest debate:** Whether log-based multiplication or a 64KB direct-lookup table is faster for Reed-Solomon on modern processors. **Open questions** - Could this crate be used as a drop-in for goestools' GOES satellite downlink decoding without a full Rust rewrite? - Is log-based multiplication actually faster than a 64KB lookup table for Reed-Solomon on modern hardware? - Are LDPC codes planned as a future addition? **Highlights** > Oh! Gotcha! I put a table in the README that lays it all out https://github.com/brian-armstrong/fec#performance tldr: My library matches or beats libfec's SSE2 assembly for convolutional codes and pretty steadily beats it in Reed-Solomon. For the convolutional codes, my crate is using a generic, templated decoder rather than hand-written assembly, so it was nice to see that I could match the performance. > — [brian-armstrong on hackernews](https://news.ycombinator.com/item?id=49180980) > I got caught out by my Australianism! "How do you find the speed of the Rust version of your FEC vs, the C version?" translates from "Australian" to "English" as: "What is the speed of the Rust version of your FEC vs, the C version? Though it was interesting to know how you do it. I'm interested in the speed, as I once looked into using Rust for a signal processing project, but ultimately went with C++ because the team wasn't familiar with Rust. At the time, it seemed to me that Rust had the potential to go faster. > — [femto on hackernews · 1 comments](https://news.ycombinator.com/item?id=49180659) > I was looking at the reed Solomon implementation. I've done a few of those in the past! I note that you are using logs for multiplication. I always used to use a 64kb table for direct lookup, though maybe that isn't faster on modern processors? Next LDPC codes? > — [nickcw on hackernews](https://news.ycombinator.com/item?id=49180683) **Source threads** - [hackernews](https://news.ycombinator.com/item?id=49176212) · 43 points · 9 comments ## Similar posts on daily.dev - [Rust core library partly polished for industrial safety spec](https://daily.dev/posts/rust-core-library-partly-polished-for-industrial-safety-spec-kvgfypftu) · The Register · 8 upvotes · 1 comments - [Ferrocene 26.05.0 now available\!](https://daily.dev/posts/ferrocene-26-05-0-now-available--ylnkb994l) · Ferrous Systems · 5 upvotes · 0 comments --- Tags: [#rust](https://daily.dev/tags/rust) [View this post on daily.dev](https://daily.dev/posts/show-hn-simd-viterbi-decoder-in-rust-bi668xjso) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Show HN: SIMD Viterbi Decoder in Rust","url":"https://daily.dev/posts/show-hn-simd-viterbi-decoder-in-rust-bi668xjso","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/show-hn-simd-viterbi-decoder-in-rust-bi668xjso"},"datePublished":"2026-08-05T05:23:18.531Z","dateModified":"2026-08-05T10:53:53.192Z","description":"A new Rust crate called `fec` implements forward error correction algorithms for SDR, space, and satellite applications. 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