livepeer / livepeer/go-livepeer

Research transcoding quality issues

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#2,741 0 comments 0 reactions 1 assignee View on GitHub

@thomshutt is already working on this.

Since Feb 7, 2023.

area: transcoding
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Go
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Description

We have encountered visual artifacts in transcoded videos on multiple occasions. R&D efforts are required to look into possible causes. Some leads are:

  • encoding with constant bitrate instead of constant quality
  • not using correct parameters for Nvidia encoder
  • "flush frames" used to clear Nvenc buffer between segments impacting encoder's internal state
  • re-initialization between segments affecting the quality of software encoding
  • suboptimal encoding parameters
  • scaling interpolation specifics of scale_cuda filter used with Nvenc

The first step should be to create a list of transcoded videos, where the issues are present, along with source videos. One of the recent cases encountered (see videos side by side): https://github.com/livepeer/go-livepeer/issues/2654

CC: @Thulinma @thomshutt @AlexKordic

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