i chatted with dale he is on board with moving lines to ffmpeg demuxer tests  can you take that on  it sounds like you have created a new channel for the decoder to inform the demuxer of a config change  if so  one thing to be aware of  assuming you are still using our decoder stream  is that signalling kconfigchanged from the demuxer will result in a flush of the decoder  many config changes actually require a different decoder  so this makes sense  but in your case  this is probably wasteful  for videos that change size mid way through  we just signal the new size to the upper layers and avoid the heavy decoder flush  