[FFmpeg-devel] GSoC 2008 qualification task

[Benjamin Larsson]

Michael Niedermayer wrote:
> On Fri, Mar 28, 2008 at 07:05:21PM +0100, Tomasz Z.ernicki wrote:
>> Hello,
>>   My name is Tomasz Z.ernicki. I would like to participate in the GSoC 2008. I have some DSP and audio coding background as well as experience in C programming.
>>   According to the ?Idea List? I would like to choose ?AAC-LC Encoder? as my primary GSoC task.
> 
>>   On the other hand I want to choose ?Nellymoser forward transform? as my qualification task.
> 
> See libavcodec/nellymoserdec.c theres a imdct some reordering, windowing
> and stuff :)
> Goal is a clean inverse transform of this transform. It has to be fast (no
> O(n^3) matrix multiply!) good news is, all building blocks should be already
> written (we have mdct, fft, ... code)
> I also think you should write some selftest code to ensure that your transform
> works correctly that is your transform -> existing transform is (nearly) the
> same as what was input at the start.
> And i think benjamin will want to comment on this / correct me ...
> 

It's correct. But you need to use the FFmpeg mdct function and then
perform some shuffling so the samples will be decoded by the nellymoser
decoder transform. It is basically the first step of a nellymoser encoder.

MvH
Benjamin Larsson