better record

[SArpnt]

currently record includes things like pausing and lag and must be recorded in realtime

ideally it would just give a dialogue to output a range of time, and other features such as output format

generating audio not in realtime can be done with an OfflineAudioContext, and the separate audio context allows configuring an output file sample rate to modify interpolation, for example if the song is 8000hz, an output file of 48000hz would likely be ideal.

it would also be good to be able to select other audio formats, opus has better quality for size than ogg, flac is lossless, container formats such as mkv or webm can fix support where the opus container isn't detected properly, and video formats can be used to show an oscillioscope