Extending MediaRecorder to record from Web Audio node faster than real time?

Hi all,
  Currently MediaRecorder only records data from media stream, AIUI [1], is a real time source. That means recording would take as long as content duration.
  Some use cases, such as cropping and cropping 1st half of an one hour speech audio clip, would not be very useful if saving the result needs such a long time to complete.
  Web Audio API already defines OfflineAudioContext [2] to support processing faster than real time use cases.
  By adding a new Constructor to MediaRecoder API:
    
    Constructor(AudioNode node, optional unsigned long output = 0, optional MediaRecorderOptions options)
  
  web applications can implement use cases that need to save processed audio with OfflineAudioContext and MediaRecorder.
 
  What do you think?

[1] final paragraph of http://www.w3.org/TR/mediacapture-streams/#introduction
[2] http://webaudio.github.io/web-audio-api/#the-offlineaudiocontext-interface

—
John