libhydrasdr v1.1.0: Hardware Abstraction, DDC Decimation & Lock-Free Streaming

February 7, 2026

We’re excited to announce the release of libhydrasdr v1.1.0, a major architectural upgrade for the HydraSDR RFOne platform. This release introduces a hardware-agnostic API, state-of-the-art DDC decimation with virtual sample rates, and a completely redesigned streaming engine — all already integrated into our SDR++ fork.

What’s New

Hardware Abstraction Layer (HAL)

Version 1.1.0 refactors the library into a unified API that supports multiple HydraSDR hardware variants. Applications built against libhydrasdr now automatically adapt to the connected device’s capabilities through runtime feature detection via hydrasdr_get_device_info() and a unified hydrasdr_set_gain() function covering all gain types. This means SDR applications no longer need device-specific code paths — write once, run on any HydraSDR hardware.

DDC Decimation: Virtual Sample Rates from 10 MHz Down to 39.1 kHz

The most user-visible improvement is the addition of hardware-accelerated DDC (Digital Down Conversion) decimation with factors from 2x to 64x. This creates virtual sample rates ranging from 10 MHz all the way down to 39.1 kHz, giving users precise control over their bandwidth and processing requirements.

Two decimation modes are available:

Low Bandwidth — minimizes CPU and USB bandwidth usage, ideal for narrowband monitoring
High Definition (HD) — uses higher-quality cascaded halfband filters for superior signal fidelity

The decimation pipeline employs state-of-the-art cascaded halfband filters ensuring clean, alias-free downconversion at every stage.

Selectable DDC Filter Algorithms

For advanced users, v1.1.0 offers four selectable DDC filter configurations, letting you tailor the tradeoff between CPU load and filter quality:

33-Tap — Fast, low latency (~62 dB rejection)
47-Tap — Optimized balance (~63 dB rejection)
65-Tap — Power-of-2 delay (~66 dB rejection)
83-Tap — High Performance with over 100 dB rejection

Lock-Free Streaming Architecture

The streaming engine has been completely redesigned with a decoupled USB/callback architecture featuring a lock-free SPSC (Single Producer, Single Consumer) queue and triple buffering. This eliminates contention between the USB transfer thread and the application callback, delivering approximately 2x performance improvement and rock-solid stability under heavy processing loads.

SDR++ Integration

All of these features are already available in our SDR++ nightly build. The new Source panel exposes the full sample rate selection dropdown, HD mode checkbox, and DDC algorithm selector — making it easy to configure your RFOne directly from the familiar SDR++ interface.

Download SDR++ for HydraSDR RFOne: https://github.com/hydrasdr/SDRPlusPlus/releases/tag/nightly

Getting Started

Download the latest libhydrasdr v1.1.0 release for Windows, Linux, or macOS:

libhydrasdr v1.1.0: https://github.com/hydrasdr/hydrasdr-host/releases/tag/v1.1.0

Important: After installing v1.1.0, you must reinstall SoapyHydraSDR to link against the correct library version.

For full technical details, see the complete changelog on GitHub.

Order Your HydraSDR RFOne

Don’t have an RFOne yet? Order now from DigiKey and start exploring the RF spectrum with the most affordable, compact, and extensible wideband receiver on the market.

All software is fully open source on GitHub.