[FFmpeg-devel] [PATCH] atrac decoder
Tue Jun 9 15:11:01 CEST 2009
On Tue, Jun 09, 2009 at 02:30:11PM +0200, Benjamin Larsson wrote:
> Michael Niedermayer wrote:
>> On Tue, Jun 09, 2009 at 11:00:38AM +0200, Benjamin Larsson wrote:
>>> Michael Niedermayer wrote:
>>>>> + ff_imdct_calc(mdct_context,out,spec);
>>>> cant imdct_half be used?
>>> If you/someone explain what imdct_half does. I need the complete output
>>> from the imdct per my understanding.
>> the complete output is the half output twice
>> see ff_imdct_calc_c()
> Ok, now I get it. The actual transform has symmetries but the complete
> output isn't calculated at the time. So that job is passed on to
> vector_fmul_window which does what the last part of imdct_calc did before.
> But this change needs a complete mdct window so I won't be able to remove
> the multiplication by 0 and 1. It should cut the size of the windows in
> half though. Is that good enough ?
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
The educated differ from the uneducated as much as the living from the
dead. -- Aristotle
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