> Yes, this is how the decoder figures out the break between M/S or L/R and
> intensity. But how does the encoder decide where to put the break?
Clearly
> it is a tradeoff between quality and bit usage. A naive algorithm would
> exhaustively try all 13 or 21 possibilities for intensity start bands and
> choose the one which had the highest quality/lowest bit usage (reconciling
> the two is clearly a problem), but this seems prohibitively
computationally
> intensive...
>
> I'm wondering if anyone knows of a less naive approach.
>
Here is what I think:
First of all, I would encode each time m/s instead of l/r, as (if I'm not
wrong) the middle channel can be used for the intensity encoding by just
dropping the side.
Humans are less sensitives to the direction of the sound at both extremities
of the audible freqs. So I'd start by encoding in i mode the first subband
(like in triphonic systems), and after reducing to i mode starting from the
latest band (22th) down to a given freq, according to the number of bits you
need to save. According to the DTS whitepaper you can go down to 3-4kHz.
But it's perhaps a little too simplist.
Regards,
--
Gabriel Bouvigne - France
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