[Vorbis] Floor 1 Decode

[Balatoni Denes]

Hi!

szerda 14 szeptember 2005 08.04-kor sameen eajaz ezeket a bolcs gondolatokat 
fogalmazta meg:
> As i have understood is that it is used to dequantise the "Y" values
> which are decoded from the bitstream during curve synthesis. Is this
> correct ?

No, actally the floor values are the quantizers and the residue is the 
quantized value. Hence residue*floor=original values with quantization error.

> If so why does the table have only 256 elements ? This would imply that
> the "Y" value decoded from the bitstream should has a range from "0" to
> 256. ? Does the encoder ensure this ?

The encoders I know of do so.

> In section 1.3.2.8 of the vorbis specification "However, floor vector
> values can span ~140dB (~24 bits unsigned)" .  What is this referring to
> ? Is it the final ( dequantised ) floor vector ?

Yes (the ratio between the smallest and the largest value in the 
FLOOR_fromdB_LOOKUP table).

> warm regards,
>
> Sameen

bye
Denes

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