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--></style></head><body lang="EN-US" link="blue" vlink="purple"><div class="WordSection1"><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Hi Vijay. This sounds great. Thanks for your contribution.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">I think Min Chen was just pointing out that your patch needs to make sure the number of bmvs doesn’t overflow. </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">We could hard-code the number of bmvs to keep, but we could also make this a variable that can be user configurable.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">You mention that keeping more bmvs is compute-expensive. That’s the challenge with every improvement we try to make. There is almost always a tradeoff between improved efficiency and compute cost (speed). For each patch, it would be helpful if you would share test results that show the improvement in efficiency, and the cost in performance. Some improvements may only be suitable for very slow performance presets, and we would want to keep them turned off for fast presets.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">You mention that this patch provides better coding efficiency, but you also say that BD-PSNR and BD-SSIM is same/slightly better, but no degradation. What is the effect on visual quality? We care much more about subjective visual quality than objective quality metrics. So any subjective quality analysis is also welcomed. Any patch that affects outputs will be evaluated for the effect on subjective visual quality before we commit it.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Tom</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> x265-devel [mailto:<a href="mailto:x265-devel-bounces@videolan.org">x265-devel-bounces@videolan.org</a>] <b>On Behalf Of </b>N Vijay Anand<br><b>Sent:</b> Thursday, August 4, 2016 12:07 AM<br><b>To:</b> <a href="mailto:x265-devel@videolan.org">x265-devel@videolan.org</a><br><b>Subject:</b> [x265] Motion.cpp PATCH Analysis summary</span></p><p class="MsoNormal"> </p><div><p class="MsoNormal">1. Use of 4 best motion vectors helps in improving</p><div><p class="MsoNormal"> final bmv about 25% times in simulation.</p></div><div><p class="MsoNormal"> i.e 25% times there is a lesser bcost, bmv found</p></div><div><p class="MsoNormal"> than with 1 best motion vector.</p></div><div><p class="MsoNormal"> This provides better coding efficiency, and for</p></div><div><p class="MsoNormal"> 100 frames HD seq. (jogging_girl) statistics</p></div><div><p class="MsoNormal"> changes from 1-I frame, 46 - Pframe, 53-BFrame</p></div><div><p class="MsoNormal"> to 1 I-frame, 45-Pframe, 54 -B frame.</p></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal">2. 4 is ideal, as more is compute expensive.</p></div><div><p class="MsoNormal"> This is number can be hardcoded as a const.</p></div><div><div><p class="MsoNormal">3. BD-PSNR BD-SSIM is same/slightly better with this</p></div><div><p class="MsoNormal"> improvements. But no degradation.</p></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal"> </p></div><p class="MsoNormal">-- </p><div><div><div><div><div><div><div><p class="MsoNormal">Principal Architect and Director,</p></div><div><p class="MsoNormal">TriSpace Technologies Pvt Ltd.,</p></div><div><p class="MsoNormal"> </p></div></div></div></div></div></div></div></div></div></div></body></html>