This topic provides details on the Zencoder API error: UnsupportedEncodingError.


This error occurs when we detect that the submitted file was encoded in a way we are currently unable to support.

More Information

  • Flip4Mac WMV in QuickTime Container: The Flip4Mac extensions to QuickTime encode WMV files into QuickTime containers in a proprietary way that only it can decode.
  • Multiple sample descriptions for a single stream: Some QuickTime files contain a proprietary video encoding where multiple different video tracks are placed in one stream, often as a result of cutting/editing.
  • Live HTTP Streaming manifest/playlist: We do not currently process streaming video, and the submitted file was a manifest for a stream.
  • Multichannel PCM audio with a bit depth smaller than 8: Surround/multichannel audio files which store multiple samples in a single byte.
  • Multichannel audio with more than 8 channels: We currently only support auto-mixdown of multichannel files up to 8 channels.
  • LPCM audio in SMPTE 302M stream: We currently don't support MPEG files with LPCM audio muxed into an SMPTE 302M stream.


Most of the time files that encounter this error were encoded with proprietary or application-specific encodings. Often the only way to process them is to load them in QuickTime or the software that was used to create them, and export them in a standard encoding.

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