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Topic: MS Stereo Lossless ? (Read 2412 times) previous topic - next topic
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MS Stereo Lossless ?

One question about MS Stereo.. Is it a truely lossless joint coding technique in comparison to Intensity Stereo? Can MS Stereo degrades some of directional information ?  I happened to come upon one particular example ::

  L band : L_En < L_Mask
  R band : R_En > R_Mask

  Mid_band : M_En < Mid_Mask
  Side_band : S_En < Side_Mask

  As a result, when using MS Stereo, the 2 joint bands will totally masked out  whereas, LR coding is used, the R band is not completely masked out (which is correct) ..

Wouldn't this indicates that MS Stereo destroyed some directional information?

MS Stereo Lossless ?

Reply #1 –
Quote
L band : L_En < L_Mask
R band : R_En > R_Mask

Mid_band : M_En < Mid_Mask
Side_band : S_En < Side_Mask



In this case you'd get what's called shutdown of the side channel frequency band, and the reconstructed signal will have centred artifact - actually, if you use minimum tonality of L and R bands for M and S  and BMLD  this artifact should be masked and not-noticeable, at least - according to the M/S paper.

I have similar problem, but with ATH -  you cannot apply ATH to M and S channels just by threshold in quiet control - for example,  if you use ATH for side channel - you might over-mask it and end up with side channel "holes" that cause time-variant stereo image swinging and narrowing of the sound field  which is perceived as a nasty artifact  and it happens especially when L and R channels are very similar (S channel is near 0)