Thanks for your report. The volume issue was originally conceived as a feature to prevent ear blast and distortion on startup (specifically caused by the startup sound) in Windows 8.1. We have fielded numerous questions about this and may re-examine the usefulness of this feature going forward.
The crackling sound is often caused by system resources being taxed as can sometimes happen during video playback, and some video applications are more resource efficient than others. Nonetheless, I will certainly pass your feedback on to my engineering team and hopefully a solution can be found for this.