Audio quality levels & file formats
  • 04 May 2021
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Audio quality levels & file formats

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All podcast episodes published on our platform are made available in:

  • 3 quality levels (low, medium and high)
  • 2 formats (mp3 and m4a)

Qualities

Different quality levels are employed to enable a better experience for users on slow (or expensive) internet connections while still allowing other users to receive high quality audio.

Each quality levels uses a different bitrate and sample-rate, and so determines it's size.

Quality Bitrate Sample rate Data use Connection type
Low 28k 32kHz ± 11 MB / hour 2G+
Medium 56k 32kHz ± 20 MB / hour 3G+
High 96k 44.1kHz ± 35 MB / hour ADSL/Fibre
Music content

Our quality profiles are tuned for speech-centric content like podcasts, audiobooks and news broadcasts. Ambient music, intros, outros and other jingles will still sound acceptable on the lower profiles, but only the high quality profile provides a good music listenening experience.

  • The low quality profile enables extremely small file sizes, while still the minimum fidelity for consuming speech-centric content.
  • The medium profile doubles the bitrate and produces a result that will satifisfy the majority of users.
  • The high profile doubles the bitrate again and mostly benefits users who listen on fast internet connections, in quiet environment using good sound equipment.

File formats

Different file formats are employed to ensure wide compatibility accross browsers, software and devices.

By default our web player and RSS feeds use the AAC encoded m4a version of the files, as this produces the best quality per bitrate, especially for our low quality setting.

Users can change RSS feeds to access MP3 instead, and our web player will automatically fallback to MP3 if the browser does not support AAC.



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