Pitch shifter - HTML5 Video audio FX

# Now fixed for Facebook and YouTube, plugin should handle new videos loading in and changing #

Pitch shifts audio from HTML5 Video sources on a page, without changing the playback rate (unless you want it to).

Potential use cases:

Fixing the voice of a too whiney youtuber.

A satanic version favourite movie clip.

Or a chipmunk remix of a legendary rap song.

Does NOT save any of your data to a remote server.
Does NOT load the pitch shifter on webpage until you enable it (won't needlessly slow your computer down).

Troubleshooting
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If you get no audio from the video it may be that the video is an ad from a different site and the CORS policy prevents us from altering the sound. We're looking at ways of detecting this.

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v1.5 8 Feb 2017
- Fixed bug no pitch-shifting bug on Chrome 56. Seems there was an API change/fix so thath AudioParam.setTargetAtTime(target, startTime, timeConstant) required startTime to use the currentTime from the Audio Context, not a relative time (we were using 0).

Change log:
v1.4 15 Feb 2016
- Range of semitones is -24/+24, which gives the same range as the "smooth" option, and is the same range as v1.2

v1.3 12 Feb 2016
- Fix issue with pitch shifting in tones not semitones. Thanks for the bug report guys!

v1.2 27 Oct 2015
- Pitch shift by semi-tones, experimental feature. Change mode using select box between classic smooth and new semi-tones.
- Fix bug where playback rate was not persisted when a video changed.

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Nerdy stuff:

Uses Chris Wilso's Pitch Shift effect: https://github.com/cwilso/Audio-Input-Effects

Tonal pitch shift is based off statical "line of best fit" from mmckegg: https://github.com/mmckegg/soundbank-pitch-shift
Source code: https://github.com/foxdog-studios/pitch-shifter-chrome-extension