I got my S20 in March of 2020. Due to the pandemic I didn't get to concerts / fests and record bands but that is one of my favorite things to do. I am doing that now and I am usually close to the stage and the sound on video recordings are terrible. It clips bad and is distorted. Even on a concert I was at in the 20th row. The picture is fine. I never had this problem since the S5. From there I went to S7, S9 and S10 before the S20. It for sure was great on the S9/S10.
I thought this was a pure S20 issue, but I download pictures / videos to my PC once a month as backup. I went back to March 2020 (before everything closed down due to the pandemic) when I got the phone and everything was fine then. Including being close up to the stage at a bar from what I remember was a very loud Black Sabbath tribute band.
Before I posted this I had been doing research and had tried changing several settings and nothing helped. I thought perhaps it was that I had zoom sound on but it never was. I reset all settings to default and deleted cache also (as I saw in one suggestion).
This to me seems like a software issue that must have happened with an update since I got the phone. Something related to a built in software sound limiting with the camera / video app. As proof of that, FaceBook live recordings come out much much better. Sometimes I hear a bit of clipping but nothing like the "**bleep**" I get from a normal recording. I really with I still had my S10!
Any suggestions / hints from someone who has had this problem and has solved it? I could try a factory reset but I don't see how that is different then deleting the camera app cache and resetting all the camera defaults to factory which didn't help.
Replying to my own post... since I never found a solution and tried so many things (and FB live was ok), I purchased / installed Filmic Pro (about $15 US). Totally worth it. I haven't recorded a band yet but right on the screen there is a dB meter that you use to monitor and drag a slider to limit. I already did a test with my TV blasting so I'm sure it will work. I was going to download Cinema FV-5 (about $3) but I read that support was dropped or there were no answers to issues and one person posted it didn't work on an S21. IT did have an option for bypassing AGC, but no further ways to control sounds input. I tried the free version briefly that was the same but would only allow 720P (not full HD) recording. The purchased version does allow full HD and some 4K depending on the phone. Considering the price for my S20, the extra $15 for Filmic Pro doesn't bother me at all considering all the extra features. Another benefit will be the "consistent lighting" when recording bands. Probably could have done that with the stock pro video camera, but never tried. Since I purchased the app, I can use it on my S22 when I get it also (skipped S21 as the camera was basically the same and my main interest when I upgraded from S10 to S20).