[vorbis-dev] mdct.c

[Segher Boessenkool]

Alan MacDonald wrote:
> 
> > How about this vorbis_book_decodevv_add and its children? From my profile
> > information it consumes 20.5% of time. Do you think it is
> > worth/possible/difficult to do it in hardware?
> >
> 
> All the codebook related stuff is intensive as far as bit packing because of
> the huffman coding.  Which means you have to mask and shift a lot in order
> to extract the data.  Unless you have built in bit operations in your
> hardware, it can be require a decent amount of operations.

That's why most "dvd decoder" chips have VLC code support hardware, in
addition to a generic cpu core (and some dct and/or motion compensation
accelerator stuff).

Vorbis decode tables are bigger and non-fixed, so your mileage may vary.

<p>Segher

<p>--- >8 ----
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