In Opus 1.5, we added a deep learning based redundancy encoder that enhances audio in lossy networks by embedding one second of recovery data in the padding data of each packet. The underlying algorithm behind encoding and decoding the recovery data is called the deep redundancy (DRED) algorithm. By leveraging the padding data within the packet, Opus 1.5 is fully backward compatible with prior revisions of Opus. Please see the README under the "dnn" subdirectory to understand DRED.
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