Clicks in stereo switching

Serious artifacts are observed in the bitrate switching which involves switching of different CPE modes.

The problems are in the case of MDCT->DFT->TD stereo switching where wrong st->core is set in the secondary channel of the first TD frame: TCX_CORE is set since the last MDCT stereo frame while it should be reset to ACELP_CORE in the DFT stereo.

The issue is illustrated below, from top:

  • L channel main
  • R channel main
  • L channel fixed
  • R channel fixed (BE to the R channel main)
  • element_mode

image.png

Edited by vaclav