Hi. I experienced same issue reported in https://gitlab.xiph.org/xiph/opus/issues/2026 The problem is that there are periodical(400ms) noise during DTX when the noise changed dramatically. I have found that the VAD value of silk does not affects to the DTX decision. If the background noise suddenly changes(by excessive echo cancellation, mute on/off operation, etc.) the silk generate a voice activated frame. Nevertheless, opus keeps the DTX state. As a result, decoder decode the voice activated frame every 400ms during DTX. This causes the periodical noise. I attached a fixed file. Please review this. Thanks, InGyu Kang -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.xiph.org/pipermail/opus/attachments/20181016/9da2441f/attachment-0001.html> -------------- next part -------------- A non-text attachment was scrubbed... Name: API.h Type: application/octet-stream Size: 7523 bytes Desc: not available URL: <http://lists.xiph.org/pipermail/opus/attachments/20181016/9da2441f/attachment-0003.obj> -------------- next part -------------- A non-text attachment was scrubbed... Name: opus_encoder.c Type: application/octet-stream Size: 93808 bytes Desc: not available URL: <http://lists.xiph.org/pipermail/opus/attachments/20181016/9da2441f/attachment-0004.obj> -------------- next part -------------- A non-text attachment was scrubbed... Name: enc_API.c Type: application/octet-stream Size: 31609 bytes Desc: not available URL: <http://lists.xiph.org/pipermail/opus/attachments/20181016/9da2441f/attachment-0005.obj>