[FFmpeg-devel] Mixed data type in SIMD code?

Michael Niedermayer michaelni
Tue Mar 4 00:42:51 CET 2008

On Mon, Mar 03, 2008 at 04:30:08PM -0700, Loren Merritt wrote:
> On Mon, 3 Mar 2008, Michael Niedermayer wrote:
> >
> > Also i doubt we use or ever will use packed double.
> flac encoder does. Single isn't precise enough for a linear sum of up 
> to 16k elements. Reordering the sum to a tree made it half-way 
> decent decent precision, but also made it as slow as double.

What about something like:

for(i=0; i<16000;){
    float sum=0;
        sum+= whatever[i++];
    double_sum += sum;


Or maybe even using int32_t ?

and no, ive not looked at the code ...


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Those who are too smart to engage in politics are punished by being
governed by those who are dumber. -- Plato 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: Digital signature
URL: <http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/attachments/20080304/7e9e2131/attachment.pgp>

More information about the ffmpeg-devel mailing list