[vorbis-dev] Stereo mode settings

[Sebastian Gesemann]

On Tue, 3 Feb 2004, Stephen So wrote:

> What I am attempting to do is bring lossless stereo coupling down to the
> lower quality levels in order to test out whether the high frequency
> boost is present (and caused by point stereo).

my 2 cents:

You could test this effect on monoaural files.
The "HF boost" will still be present.
It's because of heavy quantization. The SNR is *so*
low at high frequencies in low bitrate modes, that the
quantization error increases energy noticably.

Test it yourself:
- generate some random numbers p_i (around -1..1)
- round them to the nearest int q_i:=round(p_i);
- compare the "energy":
  \sum{i} p_i^2
  \sum{i} q_i^2

The bad news:
I don't know how to avoid this in general.

Ghis!
Sebastian
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