I stumbled onto a great one, on Google Play. Beware, its name resembles a bunch of other apps; on my device this one shows up labeled as
XPlayer
while on Google Play Store its listing is
Video Player All Format
The developer is
InShot Inc.
Version at this writing:
1.3.4.3
It has that slide-up-or-down gesture for volume (on the right half of the view frame) and if you just keep sliding up, it'll go past the usual 15 with "+1" tacked on, and so on. It goes up to "+15" and you get nice clean amplification. No phantom whooshes or crackles.
The app is built upon open source coding, e.g. VLC. Aside from having the desired audio boost, it's user friendly and gives me a very crisp picture. Overall I give it an A+.
BTW the suggestions earlier in this thread didn't work for me. Nothing called MX player or MXPlayer (and there are many) had the boost feature. DicePlayer: not available in the USA except as a third party .apk; and it simply would not install regardless of what I tried or where I got it. Yes, I knew to turn on the system's allowance for outside sources.
--
The plot thickens: I uninstalled VLC for Android, thinking it's superfluous now. But then on my device the name of XPlayer changed to VLC. And worse... the audio boost feature disappeared! Reinstalling VLC for Android restored the audio boost. The name XPlayer came back on my home screen. But not on the app selector you see when click-opening a file - there I see Android Video Player. Guess you have to have both apps, and pay attention. (This app uses a green circular icon.)
