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<p class=MsoNormal><span lang=EN-US>Dear all..<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>I¡¯m analyzing intra prediction part in <b>analyse.c<o:p></o:p></b></span></p>
<p class=MsoNormal><b><span lang=EN-US><o:p> </o:p></span></b></p>
<p class=MsoNormal><span lang=EN-US>There, I feel so strange for the use of <i>i_pred_mode</i>
variable.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>For 4x4 intra prediction, in x264_mb_analyse_intra
function line, we can see below<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><b><span lang=EN-US>if( b_merged_satd && i_max >=
6 )<o:p></o:p></span></b></p>
<p class=MsoNormal><b><span lang=EN-US>{<o:p></o:p></span></b></p>
<p class=MsoNormal style='text-indent:40.0pt'><b><span lang=EN-US>int satd[3];<o:p></o:p></span></b></p>
<p class=MsoNormal><b><span lang=EN-US>
h->pixf.intra_satd_x3_4x4( p_src_by, p_dst_by, satd );<o:p></o:p></span></b></p>
<p class=MsoNormal><b><span lang=EN-US>
<span style='color:red'>if( i_pred_mode < 3 )<o:p></o:p></span></span></b></p>
<p class=MsoNormal><b><span lang=EN-US style='color:red'>
satd[i_pred_mode] -= 3 *
a->i_lambda;<o:p></o:p></span></b></p>
<p class=MsoNormal><b><span lang=EN-US>
for( i=2; i>=0; i-- )<o:p></o:p></span></b></p>
<p class=MsoNormal style='text-indent:30.0pt'><b><span lang=EN-US> COPY2_IF_LT(
i_best, satd[i] + 4 * a->i_lambda, a->i_predict4x4[idx], i );<o:p></o:p></span></b></p>
<p class=MsoNormal><b><span lang=EN-US> i
= 3;<o:p></o:p></span></b></p>
<p class=MsoNormal><b><span lang=EN-US>}<o:p></o:p></span></b></p>
<p class=MsoNormal><b><span lang=EN-US>else<o:p></o:p></span></b></p>
<p class=MsoNormal><b><span lang=EN-US>
i = 0;<o:p></o:p></span></b></p>
<p class=MsoNormal><b><span lang=EN-US><o:p> </o:p></span></b></p>
<p class=MsoNormal><i><span lang=EN-US>i_pred_mode</span></i><span lang=EN-US> is
defined by below line.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><b><span lang=EN-US>int i_pred_mode =
x264_mb_predict_intra4x4_mode( h, idx );<o:p></o:p></span></b></p>
<p class=MsoNormal><b><span lang=EN-US><o:p> </o:p></span></b></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Here I have a question, ¡°Why the encoder
try to decide a best intra mode among the mode 0,1,2(Vertical, Horizontal, DC)
?¡±<b> </b></span><b><span lang=EN-US
style='font-family:Wingdings'>©¬</span><span lang=EN-US>- See the red part of
the code<o:p></o:p></span></b></p>
<p class=MsoNormal><b><span lang=EN-US><o:p> </o:p></span></b></p>
<p class=MsoNormal><span lang=EN-US>There is no time saving effect, no PSNR
preservation¡¦<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>if the QP is 26, a->i_lambda is 25 so satd[i_pred_mode]
= -75 initially.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>It¡¯s a small value for the mode decision
but I just wanna know for this reason.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-family:"Courier New"'>Looking
forward to hearing from ones who can show me the reason soon¡¦.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-family:"Courier New"'><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-family:"Courier New"'><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-family:"Courier New"'>Sincerely.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='font-family:"Courier New"'><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
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