A UK newspaper has recently published a covert video of, Paul Burrell, Princess Diana's butler in which he admits lying to an inquest into her death.

The audio on the video seems to have a decent range of frequencies and the distortion is lower than I might have expected. But throughout the video, the audio has a surprisingly noisy background. The video is at this link: Burrell says he lied To Diana's Inquest

Can anyone identify the probable cause of this noise?

If it helps, I notice that the video's soundtrack noise seems like a much louder version of the noise which I get when listening to audio files on my PC that have been made by my faulty Olympus dictation machine (model WS-320M). The dictation machine saves its recordings in WMA and, perversely, this noise only occurs on the highest quality setting which is called SHQ. The spec for Olympus's SHQ gives a sampling frequency of 44kHz with bitrate of 64kbps producing a frequency response of 100 to 15,000 Hz (but no tolerance given).

I suspect the Olympus is using one of the WMA codecs specifically for speech. See this link Windows Media Audio 9 Voice Codec

I'm looking to reduce this sort of noise on my existing recordings.

Thanks for any info.
Moonshot

Thank heaven for small mercies