[FFmpeg-devel] MDCT and AC3 encoder
Sun Oct 28 00:59:31 CEST 2007
Benjamin Larsson wrote:
> Fabrice Bellard wrote:
>> Regarding the AC3 encoder and the MDCT, I had a plan in the past to move
>> the integer FFT and MDCT to their own files so that they can be easily
>> Another task would be to modify the AC3 encoder so that it can
>> alternatively use the floating point MDCT. Does someone have similar plans ?
> Justin Ruggles has done some AC3 work with his aften AC3 encoder lib.
> And Marc Hoffman did some initial work for a fixed point frame work. It
> has stalled though. The cook decoder has code that should make it easy
> to use in fixed point mode as soon as there is a good fixed point mdct.
> Benjamin Larsson
Right now the whole encoder uses fixed-point, not just the MDCT. When I
started Aften, I used the FFmpeg AC3 encoder, but made it all floating
point. I think the hard part would be making the FFmpeg AC3 encoder use
either one. I would definitely need some help since I've never done
anything like that before.
I guess one way I could start would be to make a patch to convert the
existing encoder to floating-point. Then someone else might be able to
see how best to make it use either fixed or floating point.
What do you think?
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