64kbps audio issue

[WiS3]

I notice that when recording with 64 kbps, there is some noise in the file, some high frequency "blips"...
This only happens with 64 bitrate, no issues with higher bitrates.

I don't know how to explain really well, so here are two recordings that i made, and you can hear the difference and what i mean.

64kb bitrate:
https://chat.fr0z3n.cf/getMedia.php?type=audio&id=468b84c4e05faa87bbe657bee0f7abc0

96kb bitrate
https://chat.fr0z3n.cf/getMedia.php?type=audio&id=0698a916a50d76245fa74b5d9e18dd9c

I used your demo to record these
Google Chrome Version 50.0.2661.86 (64-bit) on Mac OSX 10.11.3

[higuma]

This is a normal behavior of a MP3 encoder with low bitrate (not a error).

Especially, LAME MP3 encoder is mostly optimized for Hi-Fi audio (typically >= 128k). It is not so good at low bitrate (it can, but result is like this).

If you need a better encoder for low bitrate (typically 64k or below), I would rather recommend Ogg Vorbis.

Try this demo and check the difference by yourself.

https://boo-higuma.ssl-lolipop.jp/gh-pages/ogg-vorbis-encoder-js/