Audio artifacts at higher frequencies when live streaming with Opus 2020-10-06 20:55:25 I've seen several folks post about audible artifacts at higher frequencies with encoding with Opus. (One suggestion was to use a low-pass filter around 15,000).I'm working on live streaming concerts from my studio to my website, using a WebRTC company in British Columbia. Video encoder is VP8, audio is Opus. Works fine, except for the upper registers of the guitar - these sound distorted, almost like they are underwater. I've heard the same thing on another provider (OpenTok) using WebRTC and the Opus encoder. It's a bit nasty.I'm unsure whether this can be addressed by implementing something in the WebRTC code (EQ or low-pass filter) or perhaps in the Opus encoder itself. I wanted to see what anyone might suggest for addressing this. Thanks so much!!
Re: Audio artifacts at higher frequencies when live streaming with Opus Reply #1 – 2020-10-07 03:20:45 I'm guessing that something other than the Opus encoder is at fault.What bitrate are you using? Will it significantly improve if the rate is set to higher bitrate, say, 160kbps?
Re: Audio artifacts at higher frequencies when live streaming with Opus Reply #2 – 2020-10-07 05:54:26 I think it might be a combination of the browser's audio processing filters and the negotiated audio bitrate.Check out this stackoverflow thread: https://stackoverflow.com/questions/33649283/how-to-set-up-sdp-for-high-quality-opus-audioQuoteMain reason for bad quality is the browser's audio processing. You need to pass audio constraints to the GetUserMedia object:{ 'channelCount':{'exact': 2}, 'echoCancellation':false, 'autoGainControl':false, 'noiseSuppression':false }
Re: Audio artifacts at higher frequencies when live streaming with Opus Reply #3 – 2020-10-07 13:00:07 Some extra links that might be helpful:https://medium.com/@trystonperry/why-is-getdisplaymedias-audio-quality-so-bad-b49ba9cfaa83https://stackoverflow.com/questions/46063374/is-it-really-possible-for-webrtc-to-stream-high-quality-audio-without-noise
Re: Audio artifacts at higher frequencies when live streaming with Opus Reply #4 – 2020-10-07 16:27:47 Thanks so much for the info!! I keep attempting to set the bitrate to anywhere between 160 - 256 but examining the SDP output in the log shows it being reset to 96. So setting it higher might address it, but the echo/noise cancellation also seems relevant. I'm getting a bit out of my depth trying to write SDP data or an SDP parser and knowing where to place it in the architecture (or whether I even can, in terms of access), but that might well be the issue - one method of pushing the stream out to the WebRTC server returns an SDP error.I'll get to work on this - thank you!