[x264-devel] Question about SAD and SATD in intra mode decision algorithm

[kenter]

Hi,
     I currently study on intra mode decision algorithm of x264, I found
that there are 2 cost computation func: SAD and SATD. I know what they
means, while I puzzled about their compression performance. I want to
implement my project by using SAD and I test some sequencies: Akiyo(QCIF),
Bridge-close(CIF) and forman(CIF) at low bit-rate condition. It seems there
are not much PSNR drop.Now, I want to ask: why not SAD as default? in which
condition the SATD will suprior to SAD?
    Thanks a lot!
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