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SEA is a low-complexity, lossy audio codec designed for embedded devices, inspired by the awesome QOA codec. Like QOA, SEA utilizes the Least Mean Squares Filter (LMS) algorithm, but it introduces variable bitrate (VBR) support and features slightly modified quantization tables. The reference implementation is written in Rust, and a compact ~250-line decoder written in C is also available for demonstration purposes.

You can test SEA in your browser here: https://daninet.github.io/sea-codec/

Key Features

• Fast, low complexity, time-domain compression. The decoder fits into ~250 lines of C code.
• Ideal for low-power embedded devices, game assets, and live streaming.
• Flat frequency response: No low-pass filtering is applied, preserving the full frequency range.
• Variable bitrate: 1.2 - 8.5 bits per sample
• Constant and variable bitrate (CBR and VBR) modes.
• Fixed frame length: Enables constant-time seeking.
• Multi-channel support: Handles up to 255 channels.
• Metadata storage: Allows embedding additional information.
• MIT License

Official git: https://github.com/Daninet/sea-codec#readme
Releases: https://github.com/Daninet/sea-codec/releases

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FlowDec (ICLR 2025) is a full-band audio codec for general audio sampled at 48 kHz that combines non-adversarial codec training with a stochastic postfilter based on a novel conditional flow matching method.

From abstract:

Compared to the prior work ScoreDec which is based on score matching, we generalize from speech to general audio and move from 24 kbit/s to as low as 4 kbit/s, while improving output quality and reducing the required postfilter DNN evaluations from 60 to 6 without any fine-tuning or distillation techniques.

DEMO: https://sp-uhh.github.io/FlowDec/

License: Creative Commons Attribution-NonCommercial 4.0 International License
Official git: https://github.com/facebookresearch/FlowDec#readme

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Hydrogen Audio has now accumulated over a million posts, 100,000 topics and 125K members.

It has also been running for close to 25 years.

Certainly has the legs, and here to stay.